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consolidator.js
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consolidator.js
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/**
* @preserve Copyright 2012 Robert Gust-Bardon <http://robert.gust-bardon.org/>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/**
* @fileoverview Enhances <a href="https://github.com/mishoo/UglifyJS/"
* >UglifyJS</a> with consolidation of null, Boolean, and String values.
* <p>Also known as aliasing, this feature has been deprecated in <a href=
* "http://closure-compiler.googlecode.com/">the Closure Compiler</a> since its
* initial release, where it is unavailable from the <abbr title=
* "command line interface">CLI</a>. The Closure Compiler allows one to log and
* influence this process. In contrast, this implementation does not introduce
* any variable declarations in global code and derives String values from
* identifier names used as property accessors.</p>
* <p>Consolidating literals may worsen the data compression ratio when an <a
* href="http://tools.ietf.org/html/rfc2616#section-3.5">encoding
* transformation</a> is applied. For instance, <a href=
* "http://code.jquery.com/jquery-1.7.1.js">jQuery 1.7.1</a> takes 248235 bytes.
* Building it with <a href="https://github.com/mishoo/UglifyJS/tarball/v1.2.5">
* UglifyJS v1.2.5</a> results in 93647 bytes (37.73% of the original) which are
* then compressed to 33154 bytes (13.36% of the original) using <a href=
* "http://linux.die.net/man/1/gzip">gzip(1)</a>. Building it with the same
* version of UglifyJS 1.2.5 patched with the implementation of consolidation
* results in 80784 bytes (a decrease of 12863 bytes, i.e. 13.74%, in comparison
* to the aforementioned 93647 bytes) which are then compressed to 34013 bytes
* (an increase of 859 bytes, i.e. 2.59%, in comparison to the aforementioned
* 33154 bytes).</p>
* <p>Written in <a href="http://es5.github.com/#x4.2.2">the strict variant</a>
* of <a href="http://es5.github.com/">ECMA-262 5.1 Edition</a>. Encoded in <a
* href="http://tools.ietf.org/html/rfc3629">UTF-8</a>. Follows <a href=
* "http://google-styleguide.googlecode.com/svn-history/r76/trunk/javascriptguide.xml"
* >Revision 2.28 of the Google JavaScript Style Guide</a> (except for the
* discouraged use of the {@code function} tag and the {@code namespace} tag).
* 100% typed for the <a href=
* "http://closure-compiler.googlecode.com/files/compiler-20120123.tar.gz"
* >Closure Compiler Version 1741</a>.</p>
* <p>Should you find this software useful, please consider <a href=
* "https://paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=JZLW72X8FD4WG"
* >a donation</a>.</p>
* @author follow.me@RGustBardon (Robert Gust-Bardon)
* @supported Tested with:
* <ul>
* <li><a href="http://nodejs.org/dist/v0.6.10/">Node v0.6.10</a>,</li>
* <li><a href="https://github.com/mishoo/UglifyJS/tarball/v1.2.5">UglifyJS
* v1.2.5</a>.</li>
* </ul>
*/
/*global console:false, exports:true, module:false, require:false */
/*jshint sub:true */
/**
* Consolidates null, Boolean, and String values found inside an <abbr title=
* "abstract syntax tree">AST</abbr>.
* @param {!TSyntacticCodeUnit} oAbstractSyntaxTree An array-like object
* representing an <abbr title="abstract syntax tree">AST</abbr>.
* @return {!TSyntacticCodeUnit} An array-like object representing an <abbr
* title="abstract syntax tree">AST</abbr> with its null, Boolean, and
* String values consolidated.
*/
// TODO(user) Consolidation of mathematical values found in numeric literals.
// TODO(user) Unconsolidation.
// TODO(user) Consolidation of ECMA-262 6th Edition programs.
// TODO(user) Rewrite in ECMA-262 6th Edition.
exports['ast_consolidate'] = function(oAbstractSyntaxTree) {
'use strict';
/*jshint bitwise:true, curly:true, eqeqeq:true, forin:true, immed:true,
latedef:true, newcap:true, noarge:true, noempty:true, nonew:true,
onevar:true, plusplus:true, regexp:true, undef:true, strict:true,
sub:false, trailing:true */
var _,
/**
* A record consisting of data about one or more source elements.
* @constructor
* @nosideeffects
*/
TSourceElementsData = function() {
/**
* The category of the elements.
* @type {number}
* @see ESourceElementCategories
*/
this.nCategory = ESourceElementCategories.N_OTHER;
/**
* The number of occurrences (within the elements) of each primitive
* value that could be consolidated.
* @type {!Array.<!Object.<string, number>>}
*/
this.aCount = [];
this.aCount[EPrimaryExpressionCategories.N_IDENTIFIER_NAMES] = {};
this.aCount[EPrimaryExpressionCategories.N_STRING_LITERALS] = {};
this.aCount[EPrimaryExpressionCategories.N_NULL_AND_BOOLEAN_LITERALS] =
{};
/**
* Identifier names found within the elements.
* @type {!Array.<string>}
*/
this.aIdentifiers = [];
/**
* Prefixed representation Strings of each primitive value that could be
* consolidated within the elements.
* @type {!Array.<string>}
*/
this.aPrimitiveValues = [];
},
/**
* A record consisting of data about a primitive value that could be
* consolidated.
* @constructor
* @nosideeffects
*/
TPrimitiveValue = function() {
/**
* The difference in the number of terminal symbols between the original
* source text and the one with the primitive value consolidated. If the
* difference is positive, the primitive value is considered worthwhile.
* @type {number}
*/
this.nSaving = 0;
/**
* An identifier name of the variable that will be declared and assigned
* the primitive value if the primitive value is consolidated.
* @type {string}
*/
this.sName = '';
},
/**
* A record consisting of data on what to consolidate within the range of
* source elements that is currently being considered.
* @constructor
* @nosideeffects
*/
TSolution = function() {
/**
* An object whose keys are prefixed representation Strings of each
* primitive value that could be consolidated within the elements and
* whose values are corresponding data about those primitive values.
* @type {!Object.<string, {nSaving: number, sName: string}>}
* @see TPrimitiveValue
*/
this.oPrimitiveValues = {};
/**
* The difference in the number of terminal symbols between the original
* source text and the one with all the worthwhile primitive values
* consolidated.
* @type {number}
* @see TPrimitiveValue#nSaving
*/
this.nSavings = 0;
},
/**
* The processor of <abbr title="abstract syntax tree">AST</abbr>s found
* in UglifyJS.
* @namespace
* @type {!TProcessor}
*/
oProcessor = (/** @type {!TProcessor} */ require('./process')),
/**
* A record consisting of a number of constants that represent the
* difference in the number of terminal symbols between a source text with
* a modified syntactic code unit and the original one.
* @namespace
* @type {!Object.<string, number>}
*/
oWeights = {
/**
* The difference in the number of punctuators required by the bracket
* notation and the dot notation.
* <p><code>'[]'.length - '.'.length</code></p>
* @const
* @type {number}
*/
N_PROPERTY_ACCESSOR: 1,
/**
* The number of punctuators required by a variable declaration with an
* initialiser.
* <p><code>':'.length + ';'.length</code></p>
* @const
* @type {number}
*/
N_VARIABLE_DECLARATION: 2,
/**
* The number of terminal symbols required to introduce a variable
* statement (excluding its variable declaration list).
* <p><code>'var '.length</code></p>
* @const
* @type {number}
*/
N_VARIABLE_STATEMENT_AFFIXATION: 4,
/**
* The number of terminal symbols needed to enclose source elements
* within a function call with no argument values to a function with an
* empty parameter list.
* <p><code>'(function(){}());'.length</code></p>
* @const
* @type {number}
*/
N_CLOSURE: 17
},
/**
* Categories of primary expressions from which primitive values that
* could be consolidated are derivable.
* @namespace
* @enum {number}
*/
EPrimaryExpressionCategories = {
/**
* Identifier names used as property accessors.
* @type {number}
*/
N_IDENTIFIER_NAMES: 0,
/**
* String literals.
* @type {number}
*/
N_STRING_LITERALS: 1,
/**
* Null and Boolean literals.
* @type {number}
*/
N_NULL_AND_BOOLEAN_LITERALS: 2
},
/**
* Prefixes of primitive values that could be consolidated.
* The String values of the prefixes must have same number of characters.
* The prefixes must not be used in any properties defined in any version
* of <a href=
* "http://www.ecma-international.org/publications/standards/Ecma-262.htm"
* >ECMA-262</a>.
* @namespace
* @enum {string}
*/
EValuePrefixes = {
/**
* Identifies String values.
* @type {string}
*/
S_STRING: '#S',
/**
* Identifies null and Boolean values.
* @type {string}
*/
S_SYMBOLIC: '#O'
},
/**
* Categories of source elements in terms of their appropriateness of
* having their primitive values consolidated.
* @namespace
* @enum {number}
*/
ESourceElementCategories = {
/**
* Identifies a source element that includes the <a href=
* "http://es5.github.com/#x12.10">{@code with}</a> statement.
* @type {number}
*/
N_WITH: 0,
/**
* Identifies a source element that includes the <a href=
* "http://es5.github.com/#x15.1.2.1">{@code eval}</a> identifier name.
* @type {number}
*/
N_EVAL: 1,
/**
* Identifies a source element that must be excluded from the process
* unless its whole scope is examined.
* @type {number}
*/
N_EXCLUDABLE: 2,
/**
* Identifies source elements not posing any problems.
* @type {number}
*/
N_OTHER: 3
},
/**
* The list of literals (other than the String ones) whose primitive
* values can be consolidated.
* @const
* @type {!Array.<string>}
*/
A_OTHER_SUBSTITUTABLE_LITERALS = [
'null', // The null literal.
'false', // The Boolean literal {@code false}.
'true' // The Boolean literal {@code true}.
];
(/**
* Consolidates all worthwhile primitive values in a syntactic code unit.
* @param {!TSyntacticCodeUnit} oSyntacticCodeUnit An array-like object
* representing the branch of the abstract syntax tree representing the
* syntactic code unit along with its scope.
* @see TPrimitiveValue#nSaving
*/
function fExamineSyntacticCodeUnit(oSyntacticCodeUnit) {
var _,
/**
* Indicates whether the syntactic code unit represents global code.
* @type {boolean}
*/
bIsGlobal = 'toplevel' === oSyntacticCodeUnit[0],
/**
* Indicates whether the whole scope is being examined.
* @type {boolean}
*/
bIsWhollyExaminable = !bIsGlobal,
/**
* An array-like object representing source elements that constitute a
* syntactic code unit.
* @type {!TSyntacticCodeUnit}
*/
oSourceElements,
/**
* A record consisting of data about the source element that is
* currently being examined.
* @type {!TSourceElementsData}
*/
oSourceElementData,
/**
* The scope of the syntactic code unit.
* @type {!TScope}
*/
oScope,
/**
* An instance of an object that allows the traversal of an <abbr
* title="abstract syntax tree">AST</abbr>.
* @type {!TWalker}
*/
oWalker,
/**
* An object encompassing collections of functions used during the
* traversal of an <abbr title="abstract syntax tree">AST</abbr>.
* @namespace
* @type {!Object.<string, !Object.<string, function(...[*])>>}
*/
oWalkers = {
/**
* A collection of functions used during the surveyance of source
* elements.
* @namespace
* @type {!Object.<string, function(...[*])>}
*/
oSurveySourceElement: {
/**#nocode+*/ // JsDoc Toolkit 2.4.0 hides some of the keys.
/**
* Classifies the source element as excludable if it does not
* contain a {@code with} statement or the {@code eval} identifier
* name. Adds the identifier of the function and its formal
* parameters to the list of identifier names found.
* @param {string} sIdentifier The identifier of the function.
* @param {!Array.<string>} aFormalParameterList Formal parameters.
* @param {!TSyntacticCodeUnit} oFunctionBody Function code.
*/
'defun': function(
sIdentifier,
aFormalParameterList,
oFunctionBody) {
fClassifyAsExcludable();
fAddIdentifier(sIdentifier);
aFormalParameterList.forEach(fAddIdentifier);
},
/**
* Increments the count of the number of occurrences of the String
* value that is equivalent to the sequence of terminal symbols
* that constitute the encountered identifier name.
* @param {!TSyntacticCodeUnit} oExpression The nonterminal
* MemberExpression.
* @param {string} sIdentifierName The identifier name used as the
* property accessor.
* @return {!Array} The encountered branch of an <abbr title=
* "abstract syntax tree">AST</abbr> with its nonterminal
* MemberExpression traversed.
*/
'dot': function(oExpression, sIdentifierName) {
fCountPrimaryExpression(
EPrimaryExpressionCategories.N_IDENTIFIER_NAMES,
EValuePrefixes.S_STRING + sIdentifierName);
return ['dot', oWalker.walk(oExpression), sIdentifierName];
},
/**
* Adds the optional identifier of the function and its formal
* parameters to the list of identifier names found.
* @param {?string} sIdentifier The optional identifier of the
* function.
* @param {!Array.<string>} aFormalParameterList Formal parameters.
* @param {!TSyntacticCodeUnit} oFunctionBody Function code.
*/
'function': function(
sIdentifier,
aFormalParameterList,
oFunctionBody) {
if ('string' === typeof sIdentifier) {
fAddIdentifier(sIdentifier);
}
aFormalParameterList.forEach(fAddIdentifier);
},
/**
* Either increments the count of the number of occurrences of the
* encountered null or Boolean value or classifies a source element
* as containing the {@code eval} identifier name.
* @param {string} sIdentifier The identifier encountered.
*/
'name': function(sIdentifier) {
if (-1 !== A_OTHER_SUBSTITUTABLE_LITERALS.indexOf(sIdentifier)) {
fCountPrimaryExpression(
EPrimaryExpressionCategories.N_NULL_AND_BOOLEAN_LITERALS,
EValuePrefixes.S_SYMBOLIC + sIdentifier);
} else {
if ('eval' === sIdentifier) {
oSourceElementData.nCategory =
ESourceElementCategories.N_EVAL;
}
fAddIdentifier(sIdentifier);
}
},
/**
* Classifies the source element as excludable if it does not
* contain a {@code with} statement or the {@code eval} identifier
* name.
* @param {TSyntacticCodeUnit} oExpression The expression whose
* value is to be returned.
*/
'return': function(oExpression) {
fClassifyAsExcludable();
},
/**
* Increments the count of the number of occurrences of the
* encountered String value.
* @param {string} sStringValue The String value of the string
* literal encountered.
*/
'string': function(sStringValue) {
if (sStringValue.length > 0) {
fCountPrimaryExpression(
EPrimaryExpressionCategories.N_STRING_LITERALS,
EValuePrefixes.S_STRING + sStringValue);
}
},
/**
* Adds the identifier reserved for an exception to the list of
* identifier names found.
* @param {!TSyntacticCodeUnit} oTry A block of code in which an
* exception can occur.
* @param {Array} aCatch The identifier reserved for an exception
* and a block of code to handle the exception.
* @param {TSyntacticCodeUnit} oFinally An optional block of code
* to be evaluated regardless of whether an exception occurs.
*/
'try': function(oTry, aCatch, oFinally) {
if (Array.isArray(aCatch)) {
fAddIdentifier(aCatch[0]);
}
},
/**
* Classifies the source element as excludable if it does not
* contain a {@code with} statement or the {@code eval} identifier
* name. Adds the identifier of each declared variable to the list
* of identifier names found.
* @param {!Array.<!Array>} aVariableDeclarationList Variable
* declarations.
*/
'var': function(aVariableDeclarationList) {
fClassifyAsExcludable();
aVariableDeclarationList.forEach(fAddVariable);
},
/**
* Classifies a source element as containing the {@code with}
* statement.
* @param {!TSyntacticCodeUnit} oExpression An expression whose
* value is to be converted to a value of type Object and
* become the binding object of a new object environment
* record of a new lexical environment in which the statement
* is to be executed.
* @param {!TSyntacticCodeUnit} oStatement The statement to be
* executed in the augmented lexical environment.
* @return {!Array} An empty array to stop the traversal.
*/
'with': function(oExpression, oStatement) {
oSourceElementData.nCategory = ESourceElementCategories.N_WITH;
return [];
}
/**#nocode-*/ // JsDoc Toolkit 2.4.0 hides some of the keys.
},
/**
* A collection of functions used while looking for nested functions.
* @namespace
* @type {!Object.<string, function(...[*])>}
*/
oExamineFunctions: {
/**#nocode+*/ // JsDoc Toolkit 2.4.0 hides some of the keys.
/**
* Orders an examination of a nested function declaration.
* @this {!TSyntacticCodeUnit} An array-like object representing
* the branch of an <abbr title="abstract syntax tree"
* >AST</abbr> representing the syntactic code unit along with
* its scope.
* @return {!Array} An empty array to stop the traversal.
*/
'defun': function() {
fExamineSyntacticCodeUnit(this);
return [];
},
/**
* Orders an examination of a nested function expression.
* @this {!TSyntacticCodeUnit} An array-like object representing
* the branch of an <abbr title="abstract syntax tree"
* >AST</abbr> representing the syntactic code unit along with
* its scope.
* @return {!Array} An empty array to stop the traversal.
*/
'function': function() {
fExamineSyntacticCodeUnit(this);
return [];
}
/**#nocode-*/ // JsDoc Toolkit 2.4.0 hides some of the keys.
}
},
/**
* Records containing data about source elements.
* @type {Array.<TSourceElementsData>}
*/
aSourceElementsData = [],
/**
* The index (in the source text order) of the source element
* immediately following a <a href="http://es5.github.com/#x14.1"
* >Directive Prologue</a>.
* @type {number}
*/
nAfterDirectivePrologue = 0,
/**
* The index (in the source text order) of the source element that is
* currently being considered.
* @type {number}
*/
nPosition,
/**
* The index (in the source text order) of the source element that is
* the last element of the range of source elements that is currently
* being considered.
* @type {(undefined|number)}
*/
nTo,
/**
* Initiates the traversal of a source element.
* @param {!TWalker} oWalker An instance of an object that allows the
* traversal of an abstract syntax tree.
* @param {!TSyntacticCodeUnit} oSourceElement A source element from
* which the traversal should commence.
* @return {function(): !TSyntacticCodeUnit} A function that is able to
* initiate the traversal from a given source element.
*/
cContext = function(oWalker, oSourceElement) {
/**
* @return {!TSyntacticCodeUnit} A function that is able to
* initiate the traversal from a given source element.
*/
var fLambda = function() {
return oWalker.walk(oSourceElement);
};
return fLambda;
},
/**
* Classifies the source element as excludable if it does not
* contain a {@code with} statement or the {@code eval} identifier
* name.
*/
fClassifyAsExcludable = function() {
if (oSourceElementData.nCategory ===
ESourceElementCategories.N_OTHER) {
oSourceElementData.nCategory =
ESourceElementCategories.N_EXCLUDABLE;
}
},
/**
* Adds an identifier to the list of identifier names found.
* @param {string} sIdentifier The identifier to be added.
*/
fAddIdentifier = function(sIdentifier) {
if (-1 === oSourceElementData.aIdentifiers.indexOf(sIdentifier)) {
oSourceElementData.aIdentifiers.push(sIdentifier);
}
},
/**
* Adds the identifier of a variable to the list of identifier names
* found.
* @param {!Array} aVariableDeclaration A variable declaration.
*/
fAddVariable = function(aVariableDeclaration) {
fAddIdentifier(/** @type {string} */ aVariableDeclaration[0]);
},
/**
* Increments the count of the number of occurrences of the prefixed
* String representation attributed to the primary expression.
* @param {number} nCategory The category of the primary expression.
* @param {string} sName The prefixed String representation attributed
* to the primary expression.
*/
fCountPrimaryExpression = function(nCategory, sName) {
if (!oSourceElementData.aCount[nCategory].hasOwnProperty(sName)) {
oSourceElementData.aCount[nCategory][sName] = 0;
if (-1 === oSourceElementData.aPrimitiveValues.indexOf(sName)) {
oSourceElementData.aPrimitiveValues.push(sName);
}
}
oSourceElementData.aCount[nCategory][sName] += 1;
},
/**
* Consolidates all worthwhile primitive values in a range of source
* elements.
* @param {number} nFrom The index (in the source text order) of the
* source element that is the first element of the range.
* @param {number} nTo The index (in the source text order) of the
* source element that is the last element of the range.
* @param {boolean} bEnclose Indicates whether the range should be
* enclosed within a function call with no argument values to a
* function with an empty parameter list if any primitive values
* are consolidated.
* @see TPrimitiveValue#nSaving
*/
fExamineSourceElements = function(nFrom, nTo, bEnclose) {
var _,
/**
* The index of the last mangled name.
* @type {number}
*/
nIndex = oScope.cname,
/**
* The index of the source element that is currently being
* considered.
* @type {number}
*/
nPosition,
/**
* A collection of functions used during the consolidation of
* primitive values and identifier names used as property
* accessors.
* @namespace
* @type {!Object.<string, function(...[*])>}
*/
oWalkersTransformers = {
/**
* If the String value that is equivalent to the sequence of
* terminal symbols that constitute the encountered identifier
* name is worthwhile, a syntactic conversion from the dot
* notation to the bracket notation ensues with that sequence
* being substituted by an identifier name to which the value
* is assigned.
* Applies to property accessors that use the dot notation.
* @param {!TSyntacticCodeUnit} oExpression The nonterminal
* MemberExpression.
* @param {string} sIdentifierName The identifier name used as
* the property accessor.
* @return {!Array} A syntactic code unit that is equivalent to
* the one encountered.
* @see TPrimitiveValue#nSaving
*/
'dot': function(oExpression, sIdentifierName) {
/**
* The prefixed String value that is equivalent to the
* sequence of terminal symbols that constitute the
* encountered identifier name.
* @type {string}
*/
var sPrefixed = EValuePrefixes.S_STRING + sIdentifierName;
return oSolutionBest.oPrimitiveValues.hasOwnProperty(
sPrefixed) &&
oSolutionBest.oPrimitiveValues[sPrefixed].nSaving > 0 ?
['sub',
oWalker.walk(oExpression),
['name',
oSolutionBest.oPrimitiveValues[sPrefixed].sName]] :
['dot', oWalker.walk(oExpression), sIdentifierName];
},
/**
* If the encountered identifier is a null or Boolean literal
* and its value is worthwhile, the identifier is substituted
* by an identifier name to which that value is assigned.
* Applies to identifier names.
* @param {string} sIdentifier The identifier encountered.
* @return {!Array} A syntactic code unit that is equivalent to
* the one encountered.
* @see TPrimitiveValue#nSaving
*/
'name': function(sIdentifier) {
/**
* The prefixed representation String of the identifier.
* @type {string}
*/
var sPrefixed = EValuePrefixes.S_SYMBOLIC + sIdentifier;
return [
'name',
oSolutionBest.oPrimitiveValues.hasOwnProperty(sPrefixed) &&
oSolutionBest.oPrimitiveValues[sPrefixed].nSaving > 0 ?
oSolutionBest.oPrimitiveValues[sPrefixed].sName :
sIdentifier
];
},
/**
* If the encountered String value is worthwhile, it is
* substituted by an identifier name to which that value is
* assigned.
* Applies to String values.
* @param {string} sStringValue The String value of the string
* literal encountered.
* @return {!Array} A syntactic code unit that is equivalent to
* the one encountered.
* @see TPrimitiveValue#nSaving
*/
'string': function(sStringValue) {
/**
* The prefixed representation String of the primitive value
* of the literal.
* @type {string}
*/
var sPrefixed =
EValuePrefixes.S_STRING + sStringValue;
return oSolutionBest.oPrimitiveValues.hasOwnProperty(
sPrefixed) &&
oSolutionBest.oPrimitiveValues[sPrefixed].nSaving > 0 ?
['name',
oSolutionBest.oPrimitiveValues[sPrefixed].sName] :
['string', sStringValue];
}
},
/**
* Such data on what to consolidate within the range of source
* elements that is currently being considered that lead to the
* greatest known reduction of the number of the terminal symbols
* in comparison to the original source text.
* @type {!TSolution}
*/
oSolutionBest = new TSolution(),
/**
* Data representing an ongoing attempt to find a better
* reduction of the number of the terminal symbols in comparison
* to the original source text than the best one that is
* currently known.
* @type {!TSolution}
* @see oSolutionBest
*/
oSolutionCandidate = new TSolution(),
/**
* A record consisting of data about the range of source elements
* that is currently being examined.
* @type {!TSourceElementsData}
*/
oSourceElementsData = new TSourceElementsData(),
/**
* Variable declarations for each primitive value that is to be
* consolidated within the elements.
* @type {!Array.<!Array>}
*/
aVariableDeclarations = [],
/**
* Augments a list with a prefixed representation String.
* @param {!Array.<string>} aList A list that is to be augmented.
* @return {function(string)} A function that augments a list
* with a prefixed representation String.
*/
cAugmentList = function(aList) {
/**
* @param {string} sPrefixed Prefixed representation String of
* a primitive value that could be consolidated within the
* elements.
*/
var fLambda = function(sPrefixed) {
if (-1 === aList.indexOf(sPrefixed)) {
aList.push(sPrefixed);
}
};
return fLambda;
},
/**
* Adds the number of occurrences of a primitive value of a given
* category that could be consolidated in the source element with
* a given index to the count of occurrences of that primitive
* value within the range of source elements that is currently
* being considered.
* @param {number} nPosition The index (in the source text order)
* of a source element.
* @param {number} nCategory The category of the primary
* expression from which the primitive value is derived.
* @return {function(string)} A function that performs the
* addition.
* @see cAddOccurrencesInCategory
*/
cAddOccurrences = function(nPosition, nCategory) {
/**
* @param {string} sPrefixed The prefixed representation String
* of a primitive value.
*/
var fLambda = function(sPrefixed) {
if (!oSourceElementsData.aCount[nCategory].hasOwnProperty(
sPrefixed)) {
oSourceElementsData.aCount[nCategory][sPrefixed] = 0;
}
oSourceElementsData.aCount[nCategory][sPrefixed] +=
aSourceElementsData[nPosition].aCount[nCategory][
sPrefixed];
};
return fLambda;
},
/**
* Adds the number of occurrences of each primitive value of a
* given category that could be consolidated in the source
* element with a given index to the count of occurrences of that
* primitive values within the range of source elements that is
* currently being considered.
* @param {number} nPosition The index (in the source text order)
* of a source element.
* @return {function(number)} A function that performs the
* addition.
* @see fAddOccurrences
*/
cAddOccurrencesInCategory = function(nPosition) {
/**
* @param {number} nCategory The category of the primary
* expression from which the primitive value is derived.
*/
var fLambda = function(nCategory) {
Object.keys(
aSourceElementsData[nPosition].aCount[nCategory]
).forEach(cAddOccurrences(nPosition, nCategory));
};
return fLambda;
},
/**
* Adds the number of occurrences of each primitive value that
* could be consolidated in the source element with a given index
* to the count of occurrences of that primitive values within
* the range of source elements that is currently being
* considered.
* @param {number} nPosition The index (in the source text order)
* of a source element.
*/
fAddOccurrences = function(nPosition) {
Object.keys(aSourceElementsData[nPosition].aCount).forEach(
cAddOccurrencesInCategory(nPosition));
},
/**
* Creates a variable declaration for a primitive value if that
* primitive value is to be consolidated within the elements.
* @param {string} sPrefixed Prefixed representation String of a
* primitive value that could be consolidated within the
* elements.
* @see aVariableDeclarations
*/
cAugmentVariableDeclarations = function(sPrefixed) {
if (oSolutionBest.oPrimitiveValues[sPrefixed].nSaving > 0) {
aVariableDeclarations.push([
oSolutionBest.oPrimitiveValues[sPrefixed].sName,
[0 === sPrefixed.indexOf(EValuePrefixes.S_SYMBOLIC) ?
'name' : 'string',
sPrefixed.substring(EValuePrefixes.S_SYMBOLIC.length)]
]);
}
},
/**
* Sorts primitive values with regard to the difference in the
* number of terminal symbols between the original source text
* and the one with those primitive values consolidated.
* @param {string} sPrefixed0 The prefixed representation String
* of the first of the two primitive values that are being
* compared.
* @param {string} sPrefixed1 The prefixed representation String
* of the second of the two primitive values that are being
* compared.
* @return {number}
* <dl>
* <dt>-1</dt>
* <dd>if the first primitive value must be placed before
* the other one,</dd>
* <dt>0</dt>
* <dd>if the first primitive value may be placed before
* the other one,</dd>
* <dt>1</dt>
* <dd>if the first primitive value must not be placed
* before the other one.</dd>
* </dl>
* @see TSolution.oPrimitiveValues
*/
cSortPrimitiveValues = function(sPrefixed0, sPrefixed1) {
/**
* The difference between:
* <ol>
* <li>the difference in the number of terminal symbols
* between the original source text and the one with the
* first primitive value consolidated, and</li>
* <li>the difference in the number of terminal symbols
* between the original source text and the one with the
* second primitive value consolidated.</li>
* </ol>
* @type {number}
*/
var nDifference =
oSolutionCandidate.oPrimitiveValues[sPrefixed0].nSaving -
oSolutionCandidate.oPrimitiveValues[sPrefixed1].nSaving;
return nDifference > 0 ? -1 : nDifference < 0 ? 1 : 0;
},
/**
* Assigns an identifier name to a primitive value and calculates
* whether instances of that primitive value are worth
* consolidating.
* @param {string} sPrefixed The prefixed representation String
* of a primitive value that is being evaluated.
*/
fEvaluatePrimitiveValue = function(sPrefixed) {
var _,
/**
* The index of the last mangled name.
* @type {number}
*/
nIndex,
/**
* The representation String of the primitive value that is
* being evaluated.
* @type {string}
*/
sName =
sPrefixed.substring(EValuePrefixes.S_SYMBOLIC.length),
/**
* The number of source characters taken up by the
* representation String of the primitive value that is
* being evaluated.
* @type {number}
*/
nLengthOriginal = sName.length,
/**
* The number of source characters taken up by the
* identifier name that could substitute the primitive
* value that is being evaluated.
* substituted.
* @type {number}
*/
nLengthSubstitution,
/**
* The number of source characters taken up by by the
* representation String of the primitive value that is
* being evaluated when it is represented by a string
* literal.
* @type {number}
*/
nLengthString = oProcessor.make_string(sName).length;
oSolutionCandidate.oPrimitiveValues[sPrefixed] =
new TPrimitiveValue();
do { // Find an identifier unused in this or any nested scope.
nIndex = oScope.cname;
oSolutionCandidate.oPrimitiveValues[sPrefixed].sName =
oScope.next_mangled();
} while (-1 !== oSourceElementsData.aIdentifiers.indexOf(
oSolutionCandidate.oPrimitiveValues[sPrefixed].sName));
nLengthSubstitution = oSolutionCandidate.oPrimitiveValues[
sPrefixed].sName.length;
if (0 === sPrefixed.indexOf(EValuePrefixes.S_SYMBOLIC)) {
// foo:null, or foo:null;
oSolutionCandidate.oPrimitiveValues[sPrefixed].nSaving -=
nLengthSubstitution + nLengthOriginal +
oWeights.N_VARIABLE_DECLARATION;
// null vs foo
oSolutionCandidate.oPrimitiveValues[sPrefixed].nSaving +=
oSourceElementsData.aCount[
EPrimaryExpressionCategories.
N_NULL_AND_BOOLEAN_LITERALS][sPrefixed] *
(nLengthOriginal - nLengthSubstitution);