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2011 lines
87 KiB
2011 lines
87 KiB
/*********************************************************************** |
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A JavaScript tokenizer / parser / beautifier / compressor. |
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This version is suitable for Node.js. With minimal changes (the |
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exports stuff) it should work on any JS platform. |
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This file implements some AST processors. They work on data built |
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by parse-js. |
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Exported functions: |
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- ast_mangle(ast, options) -- mangles the variable/function names |
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in the AST. Returns an AST. |
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- ast_squeeze(ast) -- employs various optimizations to make the |
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final generated code even smaller. Returns an AST. |
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- gen_code(ast, options) -- generates JS code from the AST. Pass |
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true (or an object, see the code for some options) as second |
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argument to get "pretty" (indented) code. |
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-------------------------------- (C) --------------------------------- |
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Author: Mihai Bazon |
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<mihai.bazon@gmail.com> |
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http://mihai.bazon.net/blog |
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Distributed under the BSD license: |
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Copyright 2010 (c) Mihai Bazon <mihai.bazon@gmail.com> |
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Redistribution and use in source and binary forms, with or without |
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modification, are permitted provided that the following conditions |
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are met: |
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* Redistributions of source code must retain the above |
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copyright notice, this list of conditions and the following |
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disclaimer. |
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* Redistributions in binary form must reproduce the above |
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copyright notice, this list of conditions and the following |
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disclaimer in the documentation and/or other materials |
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provided with the distribution. |
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY |
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE |
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, |
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR |
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TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF |
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THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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SUCH DAMAGE. |
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***********************************************************************/ |
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var jsp = require("./parse-js"), |
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slice = jsp.slice, |
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member = jsp.member, |
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PRECEDENCE = jsp.PRECEDENCE, |
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OPERATORS = jsp.OPERATORS; |
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/* -----[ helper for AST traversal ]----- */ |
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function ast_walker() { |
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function _vardefs(defs) { |
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return [ this[0], MAP(defs, function(def){ |
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var a = [ def[0] ]; |
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if (def.length > 1) |
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a[1] = walk(def[1]); |
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return a; |
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}) ]; |
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}; |
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function _block(statements) { |
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var out = [ this[0] ]; |
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if (statements != null) |
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out.push(MAP(statements, walk)); |
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return out; |
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}; |
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var walkers = { |
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"string": function(str) { |
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return [ this[0], str ]; |
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}, |
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"num": function(num) { |
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return [ this[0], num ]; |
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}, |
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"name": function(name) { |
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return [ this[0], name ]; |
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}, |
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"toplevel": function(statements) { |
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return [ this[0], MAP(statements, walk) ]; |
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}, |
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"block": _block, |
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"splice": _block, |
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"var": _vardefs, |
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"const": _vardefs, |
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"try": function(t, c, f) { |
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return [ |
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this[0], |
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MAP(t, walk), |
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c != null ? [ c[0], MAP(c[1], walk) ] : null, |
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f != null ? MAP(f, walk) : null |
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]; |
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}, |
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"throw": function(expr) { |
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return [ this[0], walk(expr) ]; |
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}, |
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"new": function(ctor, args) { |
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return [ this[0], walk(ctor), MAP(args, walk) ]; |
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}, |
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"switch": function(expr, body) { |
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return [ this[0], walk(expr), MAP(body, function(branch){ |
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return [ branch[0] ? walk(branch[0]) : null, |
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MAP(branch[1], walk) ]; |
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}) ]; |
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}, |
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"break": function(label) { |
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return [ this[0], label ]; |
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}, |
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"continue": function(label) { |
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return [ this[0], label ]; |
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}, |
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"conditional": function(cond, t, e) { |
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return [ this[0], walk(cond), walk(t), walk(e) ]; |
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}, |
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"assign": function(op, lvalue, rvalue) { |
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return [ this[0], op, walk(lvalue), walk(rvalue) ]; |
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}, |
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"dot": function(expr) { |
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return [ this[0], walk(expr) ].concat(slice(arguments, 1)); |
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}, |
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"call": function(expr, args) { |
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return [ this[0], walk(expr), MAP(args, walk) ]; |
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}, |
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"function": function(name, args, body) { |
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return [ this[0], name, args.slice(), MAP(body, walk) ]; |
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}, |
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"debugger": function() { |
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return [ this[0] ]; |
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}, |
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"defun": function(name, args, body) { |
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return [ this[0], name, args.slice(), MAP(body, walk) ]; |
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}, |
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"if": function(conditional, t, e) { |
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return [ this[0], walk(conditional), walk(t), walk(e) ]; |
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}, |
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"for": function(init, cond, step, block) { |
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return [ this[0], walk(init), walk(cond), walk(step), walk(block) ]; |
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}, |
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"for-in": function(vvar, key, hash, block) { |
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return [ this[0], walk(vvar), walk(key), walk(hash), walk(block) ]; |
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}, |
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"while": function(cond, block) { |
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return [ this[0], walk(cond), walk(block) ]; |
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}, |
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"do": function(cond, block) { |
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return [ this[0], walk(cond), walk(block) ]; |
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}, |
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"return": function(expr) { |
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return [ this[0], walk(expr) ]; |
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}, |
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"binary": function(op, left, right) { |
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return [ this[0], op, walk(left), walk(right) ]; |
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}, |
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"unary-prefix": function(op, expr) { |
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return [ this[0], op, walk(expr) ]; |
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}, |
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"unary-postfix": function(op, expr) { |
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return [ this[0], op, walk(expr) ]; |
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}, |
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"sub": function(expr, subscript) { |
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return [ this[0], walk(expr), walk(subscript) ]; |
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}, |
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"object": function(props) { |
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return [ this[0], MAP(props, function(p){ |
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return p.length == 2 |
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? [ p[0], walk(p[1]) ] |
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: [ p[0], walk(p[1]), p[2] ]; // get/set-ter |
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}) ]; |
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}, |
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"regexp": function(rx, mods) { |
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return [ this[0], rx, mods ]; |
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}, |
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"array": function(elements) { |
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return [ this[0], MAP(elements, walk) ]; |
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}, |
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"stat": function(stat) { |
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return [ this[0], walk(stat) ]; |
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}, |
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"seq": function() { |
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return [ this[0] ].concat(MAP(slice(arguments), walk)); |
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}, |
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"label": function(name, block) { |
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return [ this[0], name, walk(block) ]; |
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}, |
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"with": function(expr, block) { |
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return [ this[0], walk(expr), walk(block) ]; |
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}, |
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"atom": function(name) { |
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return [ this[0], name ]; |
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} |
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}; |
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var user = {}; |
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var stack = []; |
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function walk(ast) { |
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if (ast == null) |
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return null; |
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try { |
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stack.push(ast); |
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var type = ast[0]; |
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var gen = user[type]; |
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if (gen) { |
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var ret = gen.apply(ast, ast.slice(1)); |
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if (ret != null) |
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return ret; |
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} |
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gen = walkers[type]; |
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return gen.apply(ast, ast.slice(1)); |
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} finally { |
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stack.pop(); |
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} |
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}; |
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function dive(ast) { |
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if (ast == null) |
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return null; |
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try { |
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stack.push(ast); |
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return walkers[ast[0]].apply(ast, ast.slice(1)); |
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} finally { |
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stack.pop(); |
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} |
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}; |
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function with_walkers(walkers, cont){ |
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var save = {}, i; |
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for (i in walkers) if (HOP(walkers, i)) { |
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save[i] = user[i]; |
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user[i] = walkers[i]; |
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} |
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var ret = cont(); |
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for (i in save) if (HOP(save, i)) { |
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if (!save[i]) delete user[i]; |
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else user[i] = save[i]; |
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} |
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return ret; |
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}; |
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return { |
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walk: walk, |
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dive: dive, |
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with_walkers: with_walkers, |
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parent: function() { |
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return stack[stack.length - 2]; // last one is current node |
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}, |
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stack: function() { |
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return stack; |
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} |
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}; |
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}; |
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/* -----[ Scope and mangling ]----- */ |
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function Scope(parent) { |
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this.names = {}; // names defined in this scope |
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this.mangled = {}; // mangled names (orig.name => mangled) |
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this.rev_mangled = {}; // reverse lookup (mangled => orig.name) |
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this.cname = -1; // current mangled name |
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this.refs = {}; // names referenced from this scope |
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this.uses_with = false; // will become TRUE if with() is detected in this or any subscopes |
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this.uses_eval = false; // will become TRUE if eval() is detected in this or any subscopes |
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this.parent = parent; // parent scope |
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this.children = []; // sub-scopes |
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if (parent) { |
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this.level = parent.level + 1; |
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parent.children.push(this); |
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} else { |
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this.level = 0; |
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} |
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}; |
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var base54 = (function(){ |
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var DIGITS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$_"; |
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return function(num) { |
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var ret = ""; |
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do { |
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ret = DIGITS.charAt(num % 54) + ret; |
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num = Math.floor(num / 54); |
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} while (num > 0); |
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return ret; |
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}; |
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})(); |
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Scope.prototype = { |
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has: function(name) { |
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for (var s = this; s; s = s.parent) |
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if (HOP(s.names, name)) |
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return s; |
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}, |
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has_mangled: function(mname) { |
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for (var s = this; s; s = s.parent) |
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if (HOP(s.rev_mangled, mname)) |
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return s; |
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}, |
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toJSON: function() { |
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return { |
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names: this.names, |
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uses_eval: this.uses_eval, |
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uses_with: this.uses_with |
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}; |
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}, |
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next_mangled: function() { |
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// we must be careful that the new mangled name: |
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// |
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// 1. doesn't shadow a mangled name from a parent |
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// scope, unless we don't reference the original |
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// name from this scope OR from any sub-scopes! |
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// This will get slow. |
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// |
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// 2. doesn't shadow an original name from a parent |
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// scope, in the event that the name is not mangled |
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// in the parent scope and we reference that name |
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// here OR IN ANY SUBSCOPES! |
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// |
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// 3. doesn't shadow a name that is referenced but not |
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// defined (possibly global defined elsewhere). |
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for (;;) { |
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var m = base54(++this.cname), prior; |
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// case 1. |
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prior = this.has_mangled(m); |
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if (prior && this.refs[prior.rev_mangled[m]] === prior) |
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continue; |
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// case 2. |
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prior = this.has(m); |
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if (prior && prior !== this && this.refs[m] === prior && !prior.has_mangled(m)) |
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continue; |
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// case 3. |
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if (HOP(this.refs, m) && this.refs[m] == null) |
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continue; |
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// I got "do" once. :-/ |
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if (!is_identifier(m)) |
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continue; |
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return m; |
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} |
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}, |
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set_mangle: function(name, m) { |
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this.rev_mangled[m] = name; |
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return this.mangled[name] = m; |
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}, |
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get_mangled: function(name, newMangle) { |
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if (this.uses_eval || this.uses_with) return name; // no mangle if eval or with is in use |
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var s = this.has(name); |
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if (!s) return name; // not in visible scope, no mangle |
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if (HOP(s.mangled, name)) return s.mangled[name]; // already mangled in this scope |
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if (!newMangle) return name; // not found and no mangling requested |
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return s.set_mangle(name, s.next_mangled()); |
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}, |
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references: function(name) { |
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return name && !this.parent || this.uses_with || this.uses_eval || this.refs[name]; |
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}, |
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define: function(name, type) { |
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if (name != null) { |
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if (type == "var" || !HOP(this.names, name)) |
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this.names[name] = type || "var"; |
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return name; |
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} |
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} |
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}; |
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function ast_add_scope(ast) { |
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var current_scope = null; |
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var w = ast_walker(), walk = w.walk; |
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var having_eval = []; |
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function with_new_scope(cont) { |
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current_scope = new Scope(current_scope); |
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current_scope.labels = new Scope(); |
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var ret = current_scope.body = cont(); |
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ret.scope = current_scope; |
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current_scope = current_scope.parent; |
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return ret; |
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}; |
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function define(name, type) { |
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return current_scope.define(name, type); |
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}; |
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function reference(name) { |
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current_scope.refs[name] = true; |
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}; |
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function _lambda(name, args, body) { |
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var is_defun = this[0] == "defun"; |
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return [ this[0], is_defun ? define(name, "defun") : name, args, with_new_scope(function(){ |
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if (!is_defun) define(name, "lambda"); |
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MAP(args, function(name){ define(name, "arg") }); |
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return MAP(body, walk); |
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})]; |
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}; |
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function _vardefs(type) { |
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return function(defs) { |
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MAP(defs, function(d){ |
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define(d[0], type); |
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if (d[1]) reference(d[0]); |
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}); |
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}; |
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}; |
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function _breacont(label) { |
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if (label) |
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current_scope.labels.refs[label] = true; |
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}; |
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return with_new_scope(function(){ |
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// process AST |
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var ret = w.with_walkers({ |
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"function": _lambda, |
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"defun": _lambda, |
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"label": function(name, stat) { current_scope.labels.define(name) }, |
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"break": _breacont, |
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"continue": _breacont, |
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"with": function(expr, block) { |
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for (var s = current_scope; s; s = s.parent) |
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s.uses_with = true; |
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}, |
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"var": _vardefs("var"), |
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"const": _vardefs("const"), |
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"try": function(t, c, f) { |
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if (c != null) return [ |
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this[0], |
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MAP(t, walk), |
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[ define(c[0], "catch"), MAP(c[1], walk) ], |
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f != null ? MAP(f, walk) : null |
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]; |
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}, |
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"name": function(name) { |
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if (name == "eval") |
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having_eval.push(current_scope); |
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reference(name); |
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} |
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}, function(){ |
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return walk(ast); |
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}); |
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// the reason why we need an additional pass here is |
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// that names can be used prior to their definition. |
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// scopes where eval was detected and their parents |
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// are marked with uses_eval, unless they define the |
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// "eval" name. |
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MAP(having_eval, function(scope){ |
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if (!scope.has("eval")) while (scope) { |
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scope.uses_eval = true; |
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scope = scope.parent; |
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} |
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}); |
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// for referenced names it might be useful to know |
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// their origin scope. current_scope here is the |
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// toplevel one. |
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function fixrefs(scope, i) { |
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// do children first; order shouldn't matter |
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for (i = scope.children.length; --i >= 0;) |
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fixrefs(scope.children[i]); |
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for (i in scope.refs) if (HOP(scope.refs, i)) { |
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// find origin scope and propagate the reference to origin |
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for (var origin = scope.has(i), s = scope; s; s = s.parent) { |
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s.refs[i] = origin; |
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if (s === origin) break; |
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} |
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} |
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}; |
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fixrefs(current_scope); |
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return ret; |
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}); |
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}; |
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/* -----[ mangle names ]----- */ |
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function ast_mangle(ast, options) { |
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var w = ast_walker(), walk = w.walk, scope; |
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options = options || {}; |
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function get_mangled(name, newMangle) { |
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if (!options.toplevel && !scope.parent) return name; // don't mangle toplevel |
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if (options.except && member(name, options.except)) |
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return name; |
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return scope.get_mangled(name, newMangle); |
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}; |
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function get_define(name) { |
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if (options.defines) { |
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// we always lookup a defined symbol for the current scope FIRST, so declared |
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// vars trump a DEFINE symbol, but if no such var is found, then match a DEFINE value |
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if (!scope.has(name)) { |
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if (HOP(options.defines, name)) { |
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return options.defines[name]; |
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} |
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} |
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return null; |
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} |
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}; |
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function _lambda(name, args, body) { |
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if (!options.no_functions) { |
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var is_defun = this[0] == "defun", extra; |
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if (name) { |
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if (is_defun) name = get_mangled(name); |
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else if (body.scope.references(name)) { |
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extra = {}; |
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if (!(scope.uses_eval || scope.uses_with)) |
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name = extra[name] = scope.next_mangled(); |
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else |
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extra[name] = name; |
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} |
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else name = null; |
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} |
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} |
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body = with_scope(body.scope, function(){ |
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args = MAP(args, function(name){ return get_mangled(name) }); |
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return MAP(body, walk); |
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}, extra); |
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return [ this[0], name, args, body ]; |
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}; |
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function with_scope(s, cont, extra) { |
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var _scope = scope; |
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scope = s; |
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if (extra) for (var i in extra) if (HOP(extra, i)) { |
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s.set_mangle(i, extra[i]); |
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} |
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for (var i in s.names) if (HOP(s.names, i)) { |
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get_mangled(i, true); |
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} |
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var ret = cont(); |
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ret.scope = s; |
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scope = _scope; |
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return ret; |
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}; |
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|
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function _vardefs(defs) { |
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return [ this[0], MAP(defs, function(d){ |
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return [ get_mangled(d[0]), walk(d[1]) ]; |
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}) ]; |
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}; |
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|
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function _breacont(label) { |
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if (label) return [ this[0], scope.labels.get_mangled(label) ]; |
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}; |
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|
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return w.with_walkers({ |
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"function": _lambda, |
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"defun": function() { |
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// move function declarations to the top when |
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// they are not in some block. |
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var ast = _lambda.apply(this, arguments); |
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switch (w.parent()[0]) { |
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case "toplevel": |
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case "function": |
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case "defun": |
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return MAP.at_top(ast); |
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} |
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return ast; |
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}, |
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"label": function(label, stat) { |
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if (scope.labels.refs[label]) return [ |
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this[0], |
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scope.labels.get_mangled(label, true), |
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walk(stat) |
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]; |
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return walk(stat); |
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}, |
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"break": _breacont, |
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"continue": _breacont, |
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"var": _vardefs, |
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"const": _vardefs, |
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"name": function(name) { |
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return get_define(name) || [ this[0], get_mangled(name) ]; |
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}, |
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"try": function(t, c, f) { |
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return [ this[0], |
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MAP(t, walk), |
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c != null ? [ get_mangled(c[0]), MAP(c[1], walk) ] : null, |
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f != null ? MAP(f, walk) : null ]; |
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}, |
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"toplevel": function(body) { |
|
var self = this; |
|
return with_scope(self.scope, function(){ |
|
return [ self[0], MAP(body, walk) ]; |
|
}); |
|
} |
|
}, function() { |
|
return walk(ast_add_scope(ast)); |
|
}); |
|
}; |
|
|
|
/* -----[ |
|
- compress foo["bar"] into foo.bar, |
|
- remove block brackets {} where possible |
|
- join consecutive var declarations |
|
- various optimizations for IFs: |
|
- if (cond) foo(); else bar(); ==> cond?foo():bar(); |
|
- if (cond) foo(); ==> cond&&foo(); |
|
- if (foo) return bar(); else return baz(); ==> return foo?bar():baz(); // also for throw |
|
- if (foo) return bar(); else something(); ==> {if(foo)return bar();something()} |
|
]----- */ |
|
|
|
var warn = function(){}; |
|
|
|
function best_of(ast1, ast2) { |
|
return gen_code(ast1).length > gen_code(ast2[0] == "stat" ? ast2[1] : ast2).length ? ast2 : ast1; |
|
}; |
|
|
|
function last_stat(b) { |
|
if (b[0] == "block" && b[1] && b[1].length > 0) |
|
return b[1][b[1].length - 1]; |
|
return b; |
|
} |
|
|
|
function aborts(t) { |
|
if (t) switch (last_stat(t)[0]) { |
|
case "return": |
|
case "break": |
|
case "continue": |
|
case "throw": |
|
return true; |
|
} |
|
}; |
|
|
|
function boolean_expr(expr) { |
|
return ( (expr[0] == "unary-prefix" |
|
&& member(expr[1], [ "!", "delete" ])) || |
|
|
|
(expr[0] == "binary" |
|
&& member(expr[1], [ "in", "instanceof", "==", "!=", "===", "!==", "<", "<=", ">=", ">" ])) || |
|
|
|
(expr[0] == "binary" |
|
&& member(expr[1], [ "&&", "||" ]) |
|
&& boolean_expr(expr[2]) |
|
&& boolean_expr(expr[3])) || |
|
|
|
(expr[0] == "conditional" |
|
&& boolean_expr(expr[2]) |
|
&& boolean_expr(expr[3])) || |
|
|
|
(expr[0] == "assign" |
|
&& expr[1] === true |
|
&& boolean_expr(expr[3])) || |
|
|
|
(expr[0] == "seq" |
|
&& boolean_expr(expr[expr.length - 1])) |
|
); |
|
}; |
|
|
|
function empty(b) { |
|
return !b || (b[0] == "block" && (!b[1] || b[1].length == 0)); |
|
}; |
|
|
|
function is_string(node) { |
|
return (node[0] == "string" || |
|
node[0] == "unary-prefix" && node[1] == "typeof" || |
|
node[0] == "binary" && node[1] == "+" && |
|
(is_string(node[2]) || is_string(node[3]))); |
|
}; |
|
|
|
var when_constant = (function(){ |
|
|
|
var $NOT_CONSTANT = {}; |
|
|
|
// this can only evaluate constant expressions. If it finds anything |
|
// not constant, it throws $NOT_CONSTANT. |
|
function evaluate(expr) { |
|
switch (expr[0]) { |
|
case "string": |
|
case "num": |
|
return expr[1]; |
|
case "name": |
|
case "atom": |
|
switch (expr[1]) { |
|
case "true": return true; |
|
case "false": return false; |
|
case "null": return null; |
|
} |
|
break; |
|
case "unary-prefix": |
|
switch (expr[1]) { |
|
case "!": return !evaluate(expr[2]); |
|
case "typeof": return typeof evaluate(expr[2]); |
|
case "~": return ~evaluate(expr[2]); |
|
case "-": return -evaluate(expr[2]); |
|
case "+": return +evaluate(expr[2]); |
|
} |
|
break; |
|
case "binary": |
|
var left = expr[2], right = expr[3]; |
|
switch (expr[1]) { |
|
case "&&" : return evaluate(left) && evaluate(right); |
|
case "||" : return evaluate(left) || evaluate(right); |
|
case "|" : return evaluate(left) | evaluate(right); |
|
case "&" : return evaluate(left) & evaluate(right); |
|
case "^" : return evaluate(left) ^ evaluate(right); |
|
case "+" : return evaluate(left) + evaluate(right); |
|
case "*" : return evaluate(left) * evaluate(right); |
|
case "/" : return evaluate(left) / evaluate(right); |
|
case "%" : return evaluate(left) % evaluate(right); |
|
case "-" : return evaluate(left) - evaluate(right); |
|
case "<<" : return evaluate(left) << evaluate(right); |
|
case ">>" : return evaluate(left) >> evaluate(right); |
|
case ">>>" : return evaluate(left) >>> evaluate(right); |
|
case "==" : return evaluate(left) == evaluate(right); |
|
case "===" : return evaluate(left) === evaluate(right); |
|
case "!=" : return evaluate(left) != evaluate(right); |
|
case "!==" : return evaluate(left) !== evaluate(right); |
|
case "<" : return evaluate(left) < evaluate(right); |
|
case "<=" : return evaluate(left) <= evaluate(right); |
|
case ">" : return evaluate(left) > evaluate(right); |
|
case ">=" : return evaluate(left) >= evaluate(right); |
|
case "in" : return evaluate(left) in evaluate(right); |
|
case "instanceof" : return evaluate(left) instanceof evaluate(right); |
|
} |
|
} |
|
throw $NOT_CONSTANT; |
|
}; |
|
|
|
return function(expr, yes, no) { |
|
try { |
|
var val = evaluate(expr), ast; |
|
switch (typeof val) { |
|
case "string": ast = [ "string", val ]; break; |
|
case "number": ast = [ "num", val ]; break; |
|
case "boolean": ast = [ "name", String(val) ]; break; |
|
default: |
|
if (val === null) { ast = [ "atom", "null" ]; break; } |
|
throw new Error("Can't handle constant of type: " + (typeof val)); |
|
} |
|
return yes.call(expr, ast, val); |
|
} catch(ex) { |
|
if (ex === $NOT_CONSTANT) { |
|
if (expr[0] == "binary" |
|
&& (expr[1] == "===" || expr[1] == "!==") |
|
&& ((is_string(expr[2]) && is_string(expr[3])) |
|
|| (boolean_expr(expr[2]) && boolean_expr(expr[3])))) { |
|
expr[1] = expr[1].substr(0, 2); |
|
} |
|
else if (no && expr[0] == "binary" |
|
&& (expr[1] == "||" || expr[1] == "&&")) { |
|
// the whole expression is not constant but the lval may be... |
|
try { |
|
var lval = evaluate(expr[2]); |
|
expr = ((expr[1] == "&&" && (lval ? expr[3] : lval)) || |
|
(expr[1] == "||" && (lval ? lval : expr[3])) || |
|
expr); |
|
} catch(ex2) { |
|
// IGNORE... lval is not constant |
|
} |
|
} |
|
return no ? no.call(expr, expr) : null; |
|
} |
|
else throw ex; |
|
} |
|
}; |
|
|
|
})(); |
|
|
|
function warn_unreachable(ast) { |
|
if (!empty(ast)) |
|
warn("Dropping unreachable code: " + gen_code(ast, true)); |
|
}; |
|
|
|
function prepare_ifs(ast) { |
|
var w = ast_walker(), walk = w.walk; |
|
// In this first pass, we rewrite ifs which abort with no else with an |
|
// if-else. For example: |
|
// |
|
// if (x) { |
|
// blah(); |
|
// return y; |
|
// } |
|
// foobar(); |
|
// |
|
// is rewritten into: |
|
// |
|
// if (x) { |
|
// blah(); |
|
// return y; |
|
// } else { |
|
// foobar(); |
|
// } |
|
function redo_if(statements) { |
|
statements = MAP(statements, walk); |
|
|
|
for (var i = 0; i < statements.length; ++i) { |
|
var fi = statements[i]; |
|
if (fi[0] != "if") continue; |
|
|
|
if (fi[3] && walk(fi[3])) continue; |
|
|
|
var t = walk(fi[2]); |
|
if (!aborts(t)) continue; |
|
|
|
var conditional = walk(fi[1]); |
|
|
|
var e_body = redo_if(statements.slice(i + 1)); |
|
var e = e_body.length == 1 ? e_body[0] : [ "block", e_body ]; |
|
|
|
return statements.slice(0, i).concat([ [ |
|
fi[0], // "if" |
|
conditional, // conditional |
|
t, // then |
|
e // else |
|
] ]); |
|
} |
|
|
|
return statements; |
|
}; |
|
|
|
function redo_if_lambda(name, args, body) { |
|
body = redo_if(body); |
|
return [ this[0], name, args, body ]; |
|
}; |
|
|
|
function redo_if_block(statements) { |
|
return [ this[0], statements != null ? redo_if(statements) : null ]; |
|
}; |
|
|
|
return w.with_walkers({ |
|
"defun": redo_if_lambda, |
|
"function": redo_if_lambda, |
|
"block": redo_if_block, |
|
"splice": redo_if_block, |
|
"toplevel": function(statements) { |
|
return [ this[0], redo_if(statements) ]; |
|
}, |
|
"try": function(t, c, f) { |
|
return [ |
|
this[0], |
|
redo_if(t), |
|
c != null ? [ c[0], redo_if(c[1]) ] : null, |
|
f != null ? redo_if(f) : null |
|
]; |
|
} |
|
}, function() { |
|
return walk(ast); |
|
}); |
|
}; |
|
|
|
function for_side_effects(ast, handler) { |
|
var w = ast_walker(), walk = w.walk; |
|
var $stop = {}, $restart = {}; |
|
function stop() { throw $stop }; |
|
function restart() { throw $restart }; |
|
function found(){ return handler.call(this, this, w, stop, restart) }; |
|
function unary(op) { |
|
if (op == "++" || op == "--") |
|
return found.apply(this, arguments); |
|
}; |
|
return w.with_walkers({ |
|
"try": found, |
|
"throw": found, |
|
"return": found, |
|
"new": found, |
|
"switch": found, |
|
"break": found, |
|
"continue": found, |
|
"assign": found, |
|
"call": found, |
|
"if": found, |
|
"for": found, |
|
"for-in": found, |
|
"while": found, |
|
"do": found, |
|
"return": found, |
|
"unary-prefix": unary, |
|
"unary-postfix": unary, |
|
"defun": found |
|
}, function(){ |
|
while (true) try { |
|
walk(ast); |
|
break; |
|
} catch(ex) { |
|
if (ex === $stop) break; |
|
if (ex === $restart) continue; |
|
throw ex; |
|
} |
|
}); |
|
}; |
|
|
|
function ast_lift_variables(ast) { |
|
var w = ast_walker(), walk = w.walk, scope; |
|
function do_body(body, env) { |
|
var _scope = scope; |
|
scope = env; |
|
body = MAP(body, walk); |
|
var hash = {}, names = MAP(env.names, function(type, name){ |
|
if (type != "var") return MAP.skip; |
|
if (!env.references(name)) return MAP.skip; |
|
hash[name] = true; |
|
return [ name ]; |
|
}); |
|
if (names.length > 0) { |
|
// looking for assignments to any of these variables. |
|
// we can save considerable space by moving the definitions |
|
// in the var declaration. |
|
for_side_effects([ "block", body ], function(ast, walker, stop, restart) { |
|
if (ast[0] == "assign" |
|
&& ast[1] === true |
|
&& ast[2][0] == "name" |
|
&& HOP(hash, ast[2][1])) { |
|
// insert the definition into the var declaration |
|
for (var i = names.length; --i >= 0;) { |
|
if (names[i][0] == ast[2][1]) { |
|
if (names[i][1]) // this name already defined, we must stop |
|
stop(); |
|
names[i][1] = ast[3]; // definition |
|
names.push(names.splice(i, 1)[0]); |
|
break; |
|
} |
|
} |
|
// remove this assignment from the AST. |
|
var p = walker.parent(); |
|
if (p[0] == "seq") { |
|
var a = p[2]; |
|
a.unshift(0, p.length); |
|
p.splice.apply(p, a); |
|
} |
|
else if (p[0] == "stat") { |
|
p.splice(0, p.length, "block"); // empty statement |
|
} |
|
else { |
|
stop(); |
|
} |
|
restart(); |
|
} |
|
stop(); |
|
}); |
|
body.unshift([ "var", names ]); |
|
} |
|
scope = _scope; |
|
return body; |
|
}; |
|
function _vardefs(defs) { |
|
var ret = null; |
|
for (var i = defs.length; --i >= 0;) { |
|
var d = defs[i]; |
|
if (!d[1]) continue; |
|
d = [ "assign", true, [ "name", d[0] ], d[1] ]; |
|
if (ret == null) ret = d; |
|
else ret = [ "seq", d, ret ]; |
|
} |
|
if (ret == null) { |
|
if (w.parent()[0] == "for-in") |
|
return [ "name", defs[0][0] ]; |
|
return MAP.skip; |
|
} |
|
return [ "stat", ret ]; |
|
}; |
|
function _toplevel(body) { |
|
return [ this[0], do_body(body, this.scope) ]; |
|
}; |
|
return w.with_walkers({ |
|
"function": function(name, args, body){ |
|
for (var i = args.length; --i >= 0 && !body.scope.references(args[i]);) |
|
args.pop(); |
|
if (!body.scope.references(name)) name = null; |
|
return [ this[0], name, args, do_body(body, body.scope) ]; |
|
}, |
|
"defun": function(name, args, body){ |
|
if (!scope.references(name)) return MAP.skip; |
|
for (var i = args.length; --i >= 0 && !body.scope.references(args[i]);) |
|
args.pop(); |
|
return [ this[0], name, args, do_body(body, body.scope) ]; |
|
}, |
|
"var": _vardefs, |
|
"toplevel": _toplevel |
|
}, function(){ |
|
return walk(ast_add_scope(ast)); |
|
}); |
|
}; |
|
|
|
function ast_squeeze(ast, options) { |
|
options = defaults(options, { |
|
make_seqs : true, |
|
dead_code : true, |
|
no_warnings : false, |
|
keep_comps : true |
|
}); |
|
|
|
var w = ast_walker(), walk = w.walk; |
|
|
|
function negate(c) { |
|
var not_c = [ "unary-prefix", "!", c ]; |
|
switch (c[0]) { |
|
case "unary-prefix": |
|
return c[1] == "!" && boolean_expr(c[2]) ? c[2] : not_c; |
|
case "seq": |
|
c = slice(c); |
|
c[c.length - 1] = negate(c[c.length - 1]); |
|
return c; |
|
case "conditional": |
|
return best_of(not_c, [ "conditional", c[1], negate(c[2]), negate(c[3]) ]); |
|
case "binary": |
|
var op = c[1], left = c[2], right = c[3]; |
|
if (!options.keep_comps) switch (op) { |
|
case "<=" : return [ "binary", ">", left, right ]; |
|
case "<" : return [ "binary", ">=", left, right ]; |
|
case ">=" : return [ "binary", "<", left, right ]; |
|
case ">" : return [ "binary", "<=", left, right ]; |
|
} |
|
switch (op) { |
|
case "==" : return [ "binary", "!=", left, right ]; |
|
case "!=" : return [ "binary", "==", left, right ]; |
|
case "===" : return [ "binary", "!==", left, right ]; |
|
case "!==" : return [ "binary", "===", left, right ]; |
|
case "&&" : return best_of(not_c, [ "binary", "||", negate(left), negate(right) ]); |
|
case "||" : return best_of(not_c, [ "binary", "&&", negate(left), negate(right) ]); |
|
} |
|
break; |
|
} |
|
return not_c; |
|
}; |
|
|
|
function make_conditional(c, t, e) { |
|
var make_real_conditional = function() { |
|
if (c[0] == "unary-prefix" && c[1] == "!") { |
|
return e ? [ "conditional", c[2], e, t ] : [ "binary", "||", c[2], t ]; |
|
} else { |
|
return e ? best_of( |
|
[ "conditional", c, t, e ], |
|
[ "conditional", negate(c), e, t ] |
|
) : [ "binary", "&&", c, t ]; |
|
} |
|
}; |
|
// shortcut the conditional if the expression has a constant value |
|
return when_constant(c, function(ast, val){ |
|
warn_unreachable(val ? e : t); |
|
return (val ? t : e); |
|
}, make_real_conditional); |
|
}; |
|
|
|
function rmblock(block) { |
|
if (block != null && block[0] == "block" && block[1]) { |
|
if (block[1].length == 1) |
|
block = block[1][0]; |
|
else if (block[1].length == 0) |
|
block = [ "block" ]; |
|
} |
|
return block; |
|
}; |
|
|
|
function _lambda(name, args, body) { |
|
return [ this[0], name, args, tighten(body, "lambda") ]; |
|
}; |
|
|
|
// this function does a few things: |
|
// 1. discard useless blocks |
|
// 2. join consecutive var declarations |
|
// 3. remove obviously dead code |
|
// 4. transform consecutive statements using the comma operator |
|
// 5. if block_type == "lambda" and it detects constructs like if(foo) return ... - rewrite like if (!foo) { ... } |
|
function tighten(statements, block_type) { |
|
statements = MAP(statements, walk); |
|
|
|
statements = statements.reduce(function(a, stat){ |
|
if (stat[0] == "block") { |
|
if (stat[1]) { |
|
a.push.apply(a, stat[1]); |
|
} |
|
} else { |
|
a.push(stat); |
|
} |
|
return a; |
|
}, []); |
|
|
|
statements = (function(a, prev){ |
|
statements.forEach(function(cur){ |
|
if (prev && ((cur[0] == "var" && prev[0] == "var") || |
|
(cur[0] == "const" && prev[0] == "const"))) { |
|
prev[1] = prev[1].concat(cur[1]); |
|
} else { |
|
a.push(cur); |
|
prev = cur; |
|
} |
|
}); |
|
return a; |
|
})([]); |
|
|
|
if (options.dead_code) statements = (function(a, has_quit){ |
|
statements.forEach(function(st){ |
|
if (has_quit) { |
|
if (st[0] == "function" || st[0] == "defun") { |
|
a.push(st); |
|
} |
|
else if (st[0] == "var" || st[0] == "const") { |
|
if (!options.no_warnings) |
|
warn("Variables declared in unreachable code"); |
|
st[1] = MAP(st[1], function(def){ |
|
if (def[1] && !options.no_warnings) |
|
warn_unreachable([ "assign", true, [ "name", def[0] ], def[1] ]); |
|
return [ def[0] ]; |
|
}); |
|
a.push(st); |
|
} |
|
else if (!options.no_warnings) |
|
warn_unreachable(st); |
|
} |
|
else { |
|
a.push(st); |
|
if (member(st[0], [ "return", "throw", "break", "continue" ])) |
|
has_quit = true; |
|
} |
|
}); |
|
return a; |
|
})([]); |
|
|
|
if (options.make_seqs) statements = (function(a, prev) { |
|
statements.forEach(function(cur){ |
|
if (prev && prev[0] == "stat" && cur[0] == "stat") { |
|
prev[1] = [ "seq", prev[1], cur[1] ]; |
|
} else { |
|
a.push(cur); |
|
prev = cur; |
|
} |
|
}); |
|
if (a.length >= 2 |
|
&& a[a.length-2][0] == "stat" |
|
&& (a[a.length-1][0] == "return" || a[a.length-1][0] == "throw") |
|
&& a[a.length-1][1]) |
|
{ |
|
a.splice(a.length - 2, 2, |
|
[ a[a.length-1][0], |
|
[ "seq", a[a.length-2][1], a[a.length-1][1] ]]); |
|
} |
|
return a; |
|
})([]); |
|
|
|
// this increases jQuery by 1K. Probably not such a good idea after all.. |
|
// part of this is done in prepare_ifs anyway. |
|
// if (block_type == "lambda") statements = (function(i, a, stat){ |
|
// while (i < statements.length) { |
|
// stat = statements[i++]; |
|
// if (stat[0] == "if" && !stat[3]) { |
|
// if (stat[2][0] == "return" && stat[2][1] == null) { |
|
// a.push(make_if(negate(stat[1]), [ "block", statements.slice(i) ])); |
|
// break; |
|
// } |
|
// var last = last_stat(stat[2]); |
|
// if (last[0] == "return" && last[1] == null) { |
|
// a.push(make_if(stat[1], [ "block", stat[2][1].slice(0, -1) ], [ "block", statements.slice(i) ])); |
|
// break; |
|
// } |
|
// } |
|
// a.push(stat); |
|
// } |
|
// return a; |
|
// })(0, []); |
|
|
|
return statements; |
|
}; |
|
|
|
function make_if(c, t, e) { |
|
return when_constant(c, function(ast, val){ |
|
if (val) { |
|
t = walk(t); |
|
warn_unreachable(e); |
|
return t || [ "block" ]; |
|
} else { |
|
e = walk(e); |
|
warn_unreachable(t); |
|
return e || [ "block" ]; |
|
} |
|
}, function() { |
|
return make_real_if(c, t, e); |
|
}); |
|
}; |
|
|
|
function abort_else(c, t, e) { |
|
var ret = [ [ "if", negate(c), e ] ]; |
|
if (t[0] == "block") { |
|
if (t[1]) ret = ret.concat(t[1]); |
|
} else { |
|
ret.push(t); |
|
} |
|
return walk([ "block", ret ]); |
|
}; |
|
|
|
function make_real_if(c, t, e) { |
|
c = walk(c); |
|
t = walk(t); |
|
e = walk(e); |
|
|
|
if (empty(t)) { |
|
c = negate(c); |
|
t = e; |
|
e = null; |
|
} else if (empty(e)) { |
|
e = null; |
|
} else { |
|
// if we have both else and then, maybe it makes sense to switch them? |
|
(function(){ |
|
var a = gen_code(c); |
|
var n = negate(c); |
|
var b = gen_code(n); |
|
if (b.length < a.length) { |
|
var tmp = t; |
|
t = e; |
|
e = tmp; |
|
c = n; |
|
} |
|
})(); |
|
} |
|
if (empty(e) && empty(t)) |
|
return [ "stat", c ]; |
|
var ret = [ "if", c, t, e ]; |
|
if (t[0] == "if" && empty(t[3]) && empty(e)) { |
|
ret = best_of(ret, walk([ "if", [ "binary", "&&", c, t[1] ], t[2] ])); |
|
} |
|
else if (t[0] == "stat") { |
|
if (e) { |
|
if (e[0] == "stat") |
|
ret = best_of(ret, [ "stat", make_conditional(c, t[1], e[1]) ]); |
|
else if (aborts(e)) |
|
ret = abort_else(c, t, e); |
|
} |
|
else { |
|
ret = best_of(ret, [ "stat", make_conditional(c, t[1]) ]); |
|
} |
|
} |
|
else if (e && t[0] == e[0] && (t[0] == "return" || t[0] == "throw") && t[1] && e[1]) { |
|
ret = best_of(ret, [ t[0], make_conditional(c, t[1], e[1] ) ]); |
|
} |
|
else if (e && aborts(t)) { |
|
ret = [ [ "if", c, t ] ]; |
|
if (e[0] == "block") { |
|
if (e[1]) ret = ret.concat(e[1]); |
|
} |
|
else { |
|
ret.push(e); |
|
} |
|
ret = walk([ "block", ret ]); |
|
} |
|
else if (t && aborts(e)) { |
|
ret = abort_else(c, t, e); |
|
} |
|
return ret; |
|
}; |
|
|
|
function _do_while(cond, body) { |
|
return when_constant(cond, function(cond, val){ |
|
if (!val) { |
|
warn_unreachable(body); |
|
return [ "block" ]; |
|
} else { |
|
return [ "for", null, null, null, walk(body) ]; |
|
} |
|
}); |
|
}; |
|
|
|
return w.with_walkers({ |
|
"sub": function(expr, subscript) { |
|
if (subscript[0] == "string") { |
|
var name = subscript[1]; |
|
if (is_identifier(name)) |
|
return [ "dot", walk(expr), name ]; |
|
else if (/^[1-9][0-9]*$/.test(name) || name === "0") |
|
return [ "sub", walk(expr), [ "num", parseInt(name, 10) ] ]; |
|
} |
|
}, |
|
"if": make_if, |
|
"toplevel": function(body) { |
|
return [ "toplevel", tighten(body) ]; |
|
}, |
|
"switch": function(expr, body) { |
|
var last = body.length - 1; |
|
return [ "switch", walk(expr), MAP(body, function(branch, i){ |
|
var block = tighten(branch[1]); |
|
if (i == last && block.length > 0) { |
|
var node = block[block.length - 1]; |
|
if (node[0] == "break" && !node[1]) |
|
block.pop(); |
|
} |
|
return [ branch[0] ? walk(branch[0]) : null, block ]; |
|
}) ]; |
|
}, |
|
"function": _lambda, |
|
"defun": _lambda, |
|
"block": function(body) { |
|
if (body) return rmblock([ "block", tighten(body) ]); |
|
}, |
|
"binary": function(op, left, right) { |
|
return when_constant([ "binary", op, walk(left), walk(right) ], function yes(c){ |
|
return best_of(walk(c), this); |
|
}, function no() { |
|
return function(){ |
|
if(op != "==" && op != "!=") return; |
|
var l = walk(left), r = walk(right); |
|
if(l && l[0] == "unary-prefix" && l[1] == "!" && l[2][0] == "num") |
|
left = ['num', +!l[2][1]]; |
|
else if (r && r[0] == "unary-prefix" && r[1] == "!" && r[2][0] == "num") |
|
right = ['num', +!r[2][1]]; |
|
return ["binary", op, left, right]; |
|
}() || this; |
|
}); |
|
}, |
|
"conditional": function(c, t, e) { |
|
return make_conditional(walk(c), walk(t), walk(e)); |
|
}, |
|
"try": function(t, c, f) { |
|
return [ |
|
"try", |
|
tighten(t), |
|
c != null ? [ c[0], tighten(c[1]) ] : null, |
|
f != null ? tighten(f) : null |
|
]; |
|
}, |
|
"unary-prefix": function(op, expr) { |
|
expr = walk(expr); |
|
var ret = [ "unary-prefix", op, expr ]; |
|
if (op == "!") |
|
ret = best_of(ret, negate(expr)); |
|
return when_constant(ret, function(ast, val){ |
|
return walk(ast); // it's either true or false, so minifies to !0 or !1 |
|
}, function() { return ret }); |
|
}, |
|
"name": function(name) { |
|
switch (name) { |
|
case "true": return [ "unary-prefix", "!", [ "num", 0 ]]; |
|
case "false": return [ "unary-prefix", "!", [ "num", 1 ]]; |
|
} |
|
}, |
|
"while": _do_while, |
|
"assign": function(op, lvalue, rvalue) { |
|
lvalue = walk(lvalue); |
|
rvalue = walk(rvalue); |
|
var okOps = [ '+', '-', '/', '*', '%', '>>', '<<', '>>>', '|', '^', '&' ]; |
|
if (op === true && lvalue[0] === "name" && rvalue[0] === "binary" && |
|
~okOps.indexOf(rvalue[1]) && rvalue[2][0] === "name" && |
|
rvalue[2][1] === lvalue[1]) { |
|
return [ this[0], rvalue[1], lvalue, rvalue[3] ] |
|
} |
|
return [ this[0], op, lvalue, rvalue ]; |
|
} |
|
}, function() { |
|
for (var i = 0; i < 2; ++i) { |
|
ast = prepare_ifs(ast); |
|
ast = walk(ast); |
|
} |
|
return ast; |
|
}); |
|
}; |
|
|
|
/* -----[ re-generate code from the AST ]----- */ |
|
|
|
var DOT_CALL_NO_PARENS = jsp.array_to_hash([ |
|
"name", |
|
"array", |
|
"object", |
|
"string", |
|
"dot", |
|
"sub", |
|
"call", |
|
"regexp", |
|
"defun" |
|
]); |
|
|
|
function make_string(str, ascii_only) { |
|
var dq = 0, sq = 0; |
|
str = str.replace(/[\\\b\f\n\r\t\x22\x27\u2028\u2029\0]/g, function(s){ |
|
switch (s) { |
|
case "\\": return "\\\\"; |
|
case "\b": return "\\b"; |
|
case "\f": return "\\f"; |
|
case "\n": return "\\n"; |
|
case "\r": return "\\r"; |
|
case "\t": return "\\t"; |
|
case "\u2028": return "\\u2028"; |
|
case "\u2029": return "\\u2029"; |
|
case '"': ++dq; return '"'; |
|
case "'": ++sq; return "'"; |
|
case "\0": return "\\0"; |
|
} |
|
return s; |
|
}); |
|
if (ascii_only) str = to_ascii(str); |
|
if (dq > sq) return "'" + str.replace(/\x27/g, "\\'") + "'"; |
|
else return '"' + str.replace(/\x22/g, '\\"') + '"'; |
|
}; |
|
|
|
function to_ascii(str) { |
|
return str.replace(/[\u0080-\uffff]/g, function(ch) { |
|
var code = ch.charCodeAt(0).toString(16); |
|
while (code.length < 4) code = "0" + code; |
|
return "\\u" + code; |
|
}); |
|
}; |
|
|
|
var SPLICE_NEEDS_BRACKETS = jsp.array_to_hash([ "if", "while", "do", "for", "for-in", "with" ]); |
|
|
|
function gen_code(ast, options) { |
|
options = defaults(options, { |
|
indent_start : 0, |
|
indent_level : 4, |
|
quote_keys : false, |
|
space_colon : false, |
|
beautify : false, |
|
ascii_only : false, |
|
inline_script: false |
|
}); |
|
var beautify = !!options.beautify; |
|
var indentation = 0, |
|
newline = beautify ? "\n" : "", |
|
space = beautify ? " " : ""; |
|
|
|
function encode_string(str) { |
|
var ret = make_string(str, options.ascii_only); |
|
if (options.inline_script) |
|
ret = ret.replace(/<\x2fscript([>\/\t\n\f\r ])/gi, "<\\/script$1"); |
|
return ret; |
|
}; |
|
|
|
function make_name(name) { |
|
name = name.toString(); |
|
if (options.ascii_only) |
|
name = to_ascii(name); |
|
return name; |
|
}; |
|
|
|
function indent(line) { |
|
if (line == null) |
|
line = ""; |
|
if (beautify) |
|
line = repeat_string(" ", options.indent_start + indentation * options.indent_level) + line; |
|
return line; |
|
}; |
|
|
|
function with_indent(cont, incr) { |
|
if (incr == null) incr = 1; |
|
indentation += incr; |
|
try { return cont.apply(null, slice(arguments, 1)); } |
|
finally { indentation -= incr; } |
|
}; |
|
|
|
function add_spaces(a) { |
|
if (beautify) |
|
return a.join(" "); |
|
var b = []; |
|
for (var i = 0; i < a.length; ++i) { |
|
var next = a[i + 1]; |
|
b.push(a[i]); |
|
if (next && |
|
((/[a-z0-9_\x24]$/i.test(a[i].toString()) && /^[a-z0-9_\x24]/i.test(next.toString())) || |
|
(/[\+\-]$/.test(a[i].toString()) && /^[\+\-]/.test(next.toString())))) { |
|
b.push(" "); |
|
} |
|
} |
|
return b.join(""); |
|
}; |
|
|
|
function add_commas(a) { |
|
return a.join("," + space); |
|
}; |
|
|
|
function parenthesize(expr) { |
|
var gen = make(expr); |
|
for (var i = 1; i < arguments.length; ++i) { |
|
var el = arguments[i]; |
|
if ((el instanceof Function && el(expr)) || expr[0] == el) |
|
return "(" + gen + ")"; |
|
} |
|
return gen; |
|
}; |
|
|
|
function best_of(a) { |
|
if (a.length == 1) { |
|
return a[0]; |
|
} |
|
if (a.length == 2) { |
|
var b = a[1]; |
|
a = a[0]; |
|
return a.length <= b.length ? a : b; |
|
} |
|
return best_of([ a[0], best_of(a.slice(1)) ]); |
|
}; |
|
|
|
function needs_parens(expr) { |
|
if (expr[0] == "function" || expr[0] == "object") { |
|
// dot/call on a literal function requires the |
|
// function literal itself to be parenthesized |
|
// only if it's the first "thing" in a |
|
// statement. This means that the parent is |
|
// "stat", but it could also be a "seq" and |
|
// we're the first in this "seq" and the |
|
// parent is "stat", and so on. Messy stuff, |
|
// but it worths the trouble. |
|
var a = slice(w.stack()), self = a.pop(), p = a.pop(); |
|
while (p) { |
|
if (p[0] == "stat") return true; |
|
if (((p[0] == "seq" || p[0] == "call" || p[0] == "dot" || p[0] == "sub" || p[0] == "conditional") && p[1] === self) || |
|
((p[0] == "binary" || p[0] == "assign" || p[0] == "unary-postfix") && p[2] === self)) { |
|
self = p; |
|
p = a.pop(); |
|
} else { |
|
return false; |
|
} |
|
} |
|
} |
|
return !HOP(DOT_CALL_NO_PARENS, expr[0]); |
|
}; |
|
|
|
function make_num(num) { |
|
var str = num.toString(10), a = [ str.replace(/^0\./, ".") ], m; |
|
if (Math.floor(num) === num) { |
|
if (num >= 0) { |
|
a.push("0x" + num.toString(16).toLowerCase(), // probably pointless |
|
"0" + num.toString(8)); // same. |
|
} else { |
|
a.push("-0x" + (-num).toString(16).toLowerCase(), // probably pointless |
|
"-0" + (-num).toString(8)); // same. |
|
} |
|
if ((m = /^(.*?)(0+)$/.exec(num))) { |
|
a.push(m[1] + "e" + m[2].length); |
|
} |
|
} else if ((m = /^0?\.(0+)(.*)$/.exec(num))) { |
|
a.push(m[2] + "e-" + (m[1].length + m[2].length), |
|
str.substr(str.indexOf("."))); |
|
} |
|
return best_of(a); |
|
}; |
|
|
|
var w = ast_walker(); |
|
var make = w.walk; |
|
return w.with_walkers({ |
|
"string": encode_string, |
|
"num": make_num, |
|
"name": make_name, |
|
"debugger": function(){ return "debugger" }, |
|
"toplevel": function(statements) { |
|
return make_block_statements(statements) |
|
.join(newline + newline); |
|
}, |
|
"splice": function(statements) { |
|
var parent = w.parent(); |
|
if (HOP(SPLICE_NEEDS_BRACKETS, parent)) { |
|
// we need block brackets in this case |
|
return make_block.apply(this, arguments); |
|
} else { |
|
return MAP(make_block_statements(statements, true), |
|
function(line, i) { |
|
// the first line is already indented |
|
return i > 0 ? indent(line) : line; |
|
}).join(newline); |
|
} |
|
}, |
|
"block": make_block, |
|
"var": function(defs) { |
|
return "var " + add_commas(MAP(defs, make_1vardef)) + ";"; |
|
}, |
|
"const": function(defs) { |
|
return "const " + add_commas(MAP(defs, make_1vardef)) + ";"; |
|
}, |
|
"try": function(tr, ca, fi) { |
|
var out = [ "try", make_block(tr) ]; |
|
if (ca) out.push("catch", "(" + ca[0] + ")", make_block(ca[1])); |
|
if (fi) out.push("finally", make_block(fi)); |
|
return add_spaces(out); |
|
}, |
|
"throw": function(expr) { |
|
return add_spaces([ "throw", make(expr) ]) + ";"; |
|
}, |
|
"new": function(ctor, args) { |
|
args = args.length > 0 ? "(" + add_commas(MAP(args, function(expr){ |
|
return parenthesize(expr, "seq"); |
|
})) + ")" : ""; |
|
return add_spaces([ "new", parenthesize(ctor, "seq", "binary", "conditional", "assign", function(expr){ |
|
var w = ast_walker(), has_call = {}; |
|
try { |
|
w.with_walkers({ |
|
"call": function() { throw has_call }, |
|
"function": function() { return this } |
|
}, function(){ |
|
w.walk(expr); |
|
}); |
|
} catch(ex) { |
|
if (ex === has_call) |
|
return true; |
|
throw ex; |
|
} |
|
}) + args ]); |
|
}, |
|
"switch": function(expr, body) { |
|
return add_spaces([ "switch", "(" + make(expr) + ")", make_switch_block(body) ]); |
|
}, |
|
"break": function(label) { |
|
var out = "break"; |
|
if (label != null) |
|
out += " " + make_name(label); |
|
return out + ";"; |
|
}, |
|
"continue": function(label) { |
|
var out = "continue"; |
|
if (label != null) |
|
out += " " + make_name(label); |
|
return out + ";"; |
|
}, |
|
"conditional": function(co, th, el) { |
|
return add_spaces([ parenthesize(co, "assign", "seq", "conditional"), "?", |
|
parenthesize(th, "seq"), ":", |
|
parenthesize(el, "seq") ]); |
|
}, |
|
"assign": function(op, lvalue, rvalue) { |
|
if (op && op !== true) op += "="; |
|
else op = "="; |
|
return add_spaces([ make(lvalue), op, parenthesize(rvalue, "seq") ]); |
|
}, |
|
"dot": function(expr) { |
|
var out = make(expr), i = 1; |
|
if (expr[0] == "num") { |
|
if (!/\./.test(expr[1])) |
|
out += "."; |
|
} else if (needs_parens(expr)) |
|
out = "(" + out + ")"; |
|
while (i < arguments.length) |
|
out += "." + make_name(arguments[i++]); |
|
return out; |
|
}, |
|
"call": function(func, args) { |
|
var f = make(func); |
|
if (f.charAt(0) != "(" && needs_parens(func)) |
|
f = "(" + f + ")"; |
|
return f + "(" + add_commas(MAP(args, function(expr){ |
|
return parenthesize(expr, "seq"); |
|
})) + ")"; |
|
}, |
|
"function": make_function, |
|
"defun": make_function, |
|
"if": function(co, th, el) { |
|
var out = [ "if", "(" + make(co) + ")", el ? make_then(th) : make(th) ]; |
|
if (el) { |
|
out.push("else", make(el)); |
|
} |
|
return add_spaces(out); |
|
}, |
|
"for": function(init, cond, step, block) { |
|
var out = [ "for" ]; |
|
init = (init != null ? make(init) : "").replace(/;*\s*$/, ";" + space); |
|
cond = (cond != null ? make(cond) : "").replace(/;*\s*$/, ";" + space); |
|
step = (step != null ? make(step) : "").replace(/;*\s*$/, ""); |
|
var args = init + cond + step; |
|
if (args == "; ; ") args = ";;"; |
|
out.push("(" + args + ")", make(block)); |
|
return add_spaces(out); |
|
}, |
|
"for-in": function(vvar, key, hash, block) { |
|
return add_spaces([ "for", "(" + |
|
(vvar ? make(vvar).replace(/;+$/, "") : make(key)), |
|
"in", |
|
make(hash) + ")", make(block) ]); |
|
}, |
|
"while": function(condition, block) { |
|
return add_spaces([ "while", "(" + make(condition) + ")", make(block) ]); |
|
}, |
|
"do": function(condition, block) { |
|
return add_spaces([ "do", make(block), "while", "(" + make(condition) + ")" ]) + ";"; |
|
}, |
|
"return": function(expr) { |
|
var out = [ "return" ]; |
|
if (expr != null) out.push(make(expr)); |
|
return add_spaces(out) + ";"; |
|
}, |
|
"binary": function(operator, lvalue, rvalue) { |
|
var left = make(lvalue), right = make(rvalue); |
|
// XXX: I'm pretty sure other cases will bite here. |
|
// we need to be smarter. |
|
// adding parens all the time is the safest bet. |
|
if (member(lvalue[0], [ "assign", "conditional", "seq" ]) || |
|
lvalue[0] == "binary" && PRECEDENCE[operator] > PRECEDENCE[lvalue[1]] || |
|
lvalue[0] == "function" && needs_parens(this)) { |
|
left = "(" + left + ")"; |
|
} |
|
if (member(rvalue[0], [ "assign", "conditional", "seq" ]) || |
|
rvalue[0] == "binary" && PRECEDENCE[operator] >= PRECEDENCE[rvalue[1]] && |
|
!(rvalue[1] == operator && member(operator, [ "&&", "||", "*" ]))) { |
|
right = "(" + right + ")"; |
|
} |
|
else if (!beautify && options.inline_script && (operator == "<" || operator == "<<") |
|
&& rvalue[0] == "regexp" && /^script/i.test(rvalue[1])) { |
|
right = " " + right; |
|
} |
|
return add_spaces([ left, operator, right ]); |
|
}, |
|
"unary-prefix": function(operator, expr) { |
|
var val = make(expr); |
|
if (!(expr[0] == "num" || (expr[0] == "unary-prefix" && !HOP(OPERATORS, operator + expr[1])) || !needs_parens(expr))) |
|
val = "(" + val + ")"; |
|
return operator + (jsp.is_alphanumeric_char(operator.charAt(0)) ? " " : "") + val; |
|
}, |
|
"unary-postfix": function(operator, expr) { |
|
var val = make(expr); |
|
if (!(expr[0] == "num" || (expr[0] == "unary-postfix" && !HOP(OPERATORS, operator + expr[1])) || !needs_parens(expr))) |
|
val = "(" + val + ")"; |
|
return val + operator; |
|
}, |
|
"sub": function(expr, subscript) { |
|
var hash = make(expr); |
|
if (needs_parens(expr)) |
|
hash = "(" + hash + ")"; |
|
return hash + "[" + make(subscript) + "]"; |
|
}, |
|
"object": function(props) { |
|
var obj_needs_parens = needs_parens(this); |
|
if (props.length == 0) |
|
return obj_needs_parens ? "({})" : "{}"; |
|
var out = "{" + newline + with_indent(function(){ |
|
return MAP(props, function(p){ |
|
if (p.length == 3) { |
|
// getter/setter. The name is in p[0], the arg.list in p[1][2], the |
|
// body in p[1][3] and type ("get" / "set") in p[2]. |
|
return indent(make_function(p[0], p[1][2], p[1][3], p[2])); |
|
} |
|
var key = p[0], val = parenthesize(p[1], "seq"); |
|
if (options.quote_keys) { |
|
key = encode_string(key); |
|
} else if ((typeof key == "number" || !beautify && +key + "" == key) |
|
&& parseFloat(key) >= 0) { |
|
key = make_num(+key); |
|
} else if (!is_identifier(key)) { |
|
key = encode_string(key); |
|
} |
|
return indent(add_spaces(beautify && options.space_colon |
|
? [ key, ":", val ] |
|
: [ key + ":", val ])); |
|
}).join("," + newline); |
|
}) + newline + indent("}"); |
|
return obj_needs_parens ? "(" + out + ")" : out; |
|
}, |
|
"regexp": function(rx, mods) { |
|
return "/" + rx + "/" + mods; |
|
}, |
|
"array": function(elements) { |
|
if (elements.length == 0) return "[]"; |
|
return add_spaces([ "[", add_commas(MAP(elements, function(el, i){ |
|
if (!beautify && el[0] == "atom" && el[1] == "undefined") return i === elements.length - 1 ? "," : ""; |
|
return parenthesize(el, "seq"); |
|
})), "]" ]); |
|
}, |
|
"stat": function(stmt) { |
|
return make(stmt).replace(/;*\s*$/, ";"); |
|
}, |
|
"seq": function() { |
|
return add_commas(MAP(slice(arguments), make)); |
|
}, |
|
"label": function(name, block) { |
|
return add_spaces([ make_name(name), ":", make(block) ]); |
|
}, |
|
"with": function(expr, block) { |
|
return add_spaces([ "with", "(" + make(expr) + ")", make(block) ]); |
|
}, |
|
"atom": function(name) { |
|
return make_name(name); |
|
} |
|
}, function(){ return make(ast) }); |
|
|
|
// The squeezer replaces "block"-s that contain only a single |
|
// statement with the statement itself; technically, the AST |
|
// is correct, but this can create problems when we output an |
|
// IF having an ELSE clause where the THEN clause ends in an |
|
// IF *without* an ELSE block (then the outer ELSE would refer |
|
// to the inner IF). This function checks for this case and |
|
// adds the block brackets if needed. |
|
function make_then(th) { |
|
if (th == null) return ";"; |
|
if (th[0] == "do") { |
|
// https://github.com/mishoo/UglifyJS/issues/#issue/57 |
|
// IE croaks with "syntax error" on code like this: |
|
// if (foo) do ... while(cond); else ... |
|
// we need block brackets around do/while |
|
return make_block([ th ]); |
|
} |
|
var b = th; |
|
while (true) { |
|
var type = b[0]; |
|
if (type == "if") { |
|
if (!b[3]) |
|
// no else, we must add the block |
|
return make([ "block", [ th ]]); |
|
b = b[3]; |
|
} |
|
else if (type == "while" || type == "do") b = b[2]; |
|
else if (type == "for" || type == "for-in") b = b[4]; |
|
else break; |
|
} |
|
return make(th); |
|
}; |
|
|
|
function make_function(name, args, body, keyword) { |
|
var out = keyword || "function"; |
|
if (name) { |
|
out += " " + make_name(name); |
|
} |
|
out += "(" + add_commas(MAP(args, make_name)) + ")"; |
|
out = add_spaces([ out, make_block(body) ]); |
|
return needs_parens(this) ? "(" + out + ")" : out; |
|
}; |
|
|
|
function must_has_semicolon(node) { |
|
switch (node[0]) { |
|
case "with": |
|
case "while": |
|
return empty(node[2]); // `with' or `while' with empty body? |
|
case "for": |
|
case "for-in": |
|
return empty(node[4]); // `for' with empty body? |
|
case "if": |
|
if (empty(node[2]) && !node[3]) return true; // `if' with empty `then' and no `else' |
|
if (node[3]) { |
|
if (empty(node[3])) return true; // `else' present but empty |
|
return must_has_semicolon(node[3]); // dive into the `else' branch |
|
} |
|
return must_has_semicolon(node[2]); // dive into the `then' branch |
|
} |
|
}; |
|
|
|
function make_block_statements(statements, noindent) { |
|
for (var a = [], last = statements.length - 1, i = 0; i <= last; ++i) { |
|
var stat = statements[i]; |
|
var code = make(stat); |
|
if (code != ";") { |
|
if (!beautify && i == last && !must_has_semicolon(stat)) { |
|
code = code.replace(/;+\s*$/, ""); |
|
} |
|
a.push(code); |
|
} |
|
} |
|
return noindent ? a : MAP(a, indent); |
|
}; |
|
|
|
function make_switch_block(body) { |
|
var n = body.length; |
|
if (n == 0) return "{}"; |
|
return "{" + newline + MAP(body, function(branch, i){ |
|
var has_body = branch[1].length > 0, code = with_indent(function(){ |
|
return indent(branch[0] |
|
? add_spaces([ "case", make(branch[0]) + ":" ]) |
|
: "default:"); |
|
}, 0.5) + (has_body ? newline + with_indent(function(){ |
|
return make_block_statements(branch[1]).join(newline); |
|
}) : ""); |
|
if (!beautify && has_body && i < n - 1) |
|
code += ";"; |
|
return code; |
|
}).join(newline) + newline + indent("}"); |
|
}; |
|
|
|
function make_block(statements) { |
|
if (!statements) return ";"; |
|
if (statements.length == 0) return "{}"; |
|
return "{" + newline + with_indent(function(){ |
|
return make_block_statements(statements).join(newline); |
|
}) + newline + indent("}"); |
|
}; |
|
|
|
function make_1vardef(def) { |
|
var name = def[0], val = def[1]; |
|
if (val != null) |
|
name = add_spaces([ make_name(name), "=", parenthesize(val, "seq") ]); |
|
return name; |
|
}; |
|
|
|
}; |
|
|
|
function split_lines(code, max_line_length) { |
|
var splits = [ 0 ]; |
|
jsp.parse(function(){ |
|
var next_token = jsp.tokenizer(code); |
|
var last_split = 0; |
|
var prev_token; |
|
function current_length(tok) { |
|
return tok.pos - last_split; |
|
}; |
|
function split_here(tok) { |
|
last_split = tok.pos; |
|
splits.push(last_split); |
|
}; |
|
function custom(){ |
|
var tok = next_token.apply(this, arguments); |
|
out: { |
|
if (prev_token) { |
|
if (prev_token.type == "keyword") break out; |
|
} |
|
if (current_length(tok) > max_line_length) { |
|
switch (tok.type) { |
|
case "keyword": |
|
case "atom": |
|
case "name": |
|
case "punc": |
|
split_here(tok); |
|
break out; |
|
} |
|
} |
|
} |
|
prev_token = tok; |
|
return tok; |
|
}; |
|
custom.context = function() { |
|
return next_token.context.apply(this, arguments); |
|
}; |
|
return custom; |
|
}()); |
|
return splits.map(function(pos, i){ |
|
return code.substring(pos, splits[i + 1] || code.length); |
|
}).join("\n"); |
|
}; |
|
|
|
/* -----[ Utilities ]----- */ |
|
|
|
function repeat_string(str, i) { |
|
if (i <= 0) return ""; |
|
if (i == 1) return str; |
|
var d = repeat_string(str, i >> 1); |
|
d += d; |
|
if (i & 1) d += str; |
|
return d; |
|
}; |
|
|
|
function defaults(args, defs) { |
|
var ret = {}; |
|
if (args === true) |
|
args = {}; |
|
for (var i in defs) if (HOP(defs, i)) { |
|
ret[i] = (args && HOP(args, i)) ? args[i] : defs[i]; |
|
} |
|
return ret; |
|
}; |
|
|
|
function is_identifier(name) { |
|
return /^[a-z_$][a-z0-9_$]*$/i.test(name) |
|
&& name != "this" |
|
&& !HOP(jsp.KEYWORDS_ATOM, name) |
|
&& !HOP(jsp.RESERVED_WORDS, name) |
|
&& !HOP(jsp.KEYWORDS, name); |
|
}; |
|
|
|
function HOP(obj, prop) { |
|
return Object.prototype.hasOwnProperty.call(obj, prop); |
|
}; |
|
|
|
// some utilities |
|
|
|
var MAP; |
|
|
|
(function(){ |
|
MAP = function(a, f, o) { |
|
var ret = [], top = [], i; |
|
function doit() { |
|
var val = f.call(o, a[i], i); |
|
if (val instanceof AtTop) { |
|
val = val.v; |
|
if (val instanceof Splice) { |
|
top.push.apply(top, val.v); |
|
} else { |
|
top.push(val); |
|
} |
|
} |
|
else if (val != skip) { |
|
if (val instanceof Splice) { |
|
ret.push.apply(ret, val.v); |
|
} else { |
|
ret.push(val); |
|
} |
|
} |
|
}; |
|
if (a instanceof Array) for (i = 0; i < a.length; ++i) doit(); |
|
else for (i in a) if (HOP(a, i)) doit(); |
|
return top.concat(ret); |
|
}; |
|
MAP.at_top = function(val) { return new AtTop(val) }; |
|
MAP.splice = function(val) { return new Splice(val) }; |
|
var skip = MAP.skip = {}; |
|
function AtTop(val) { this.v = val }; |
|
function Splice(val) { this.v = val }; |
|
})(); |
|
|
|
/* -----[ Exports ]----- */ |
|
|
|
exports.ast_walker = ast_walker; |
|
exports.ast_mangle = ast_mangle; |
|
exports.ast_squeeze = ast_squeeze; |
|
exports.ast_lift_variables = ast_lift_variables; |
|
exports.gen_code = gen_code; |
|
exports.ast_add_scope = ast_add_scope; |
|
exports.set_logger = function(logger) { warn = logger }; |
|
exports.make_string = make_string; |
|
exports.split_lines = split_lines; |
|
exports.MAP = MAP; |
|
|
|
// keep this last! |
|
exports.ast_squeeze_more = require("./squeeze-more").ast_squeeze_more;
|
|
|