Vitaly Puzrin
10 years ago
6 changed files with 216 additions and 119 deletions
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// Ruler is helper class to build responsibility chains from parse rules.
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// It allows:
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//
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// - easy stack rules chains
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// - getting main chain and named chains content (as arrays of functions)
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'use strict'; |
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////////////////////////////////////////////////////////////////////////////////
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// helpers
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function _class(obj) { return Object.prototype.toString.call(obj); } |
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function isFunction(obj) { return _class(obj) === '[object Function]'; } |
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function functionName(fn) { |
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var ret = fn.toString(); |
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ret = ret.substr('function '.length); |
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ret = ret.substr(0, ret.indexOf('(')); |
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return ret; |
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} |
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////////////////////////////////////////////////////////////////////////////////
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function Ruler(compileFn) { |
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this.compile = compileFn; // callback to call after each change
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// List of added rules. Each element is:
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//
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// {
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// name: XXX,
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// fn: Function(),
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// alt: [ name2, name3 ]
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// }
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//
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this.rules = []; |
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} |
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// Find rule index by name
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//
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Ruler.prototype.find = function (name) { |
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for (var i = 0; i < this.rules.length; i++) { |
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if (this.rules[i].name === name) { |
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return i; |
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} |
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} |
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return -1; |
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}; |
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// Replace/delete parser function
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//
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Ruler.prototype.at = function (name, fn, altNames) { |
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var index = this.find(name); |
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if (index === -1) { |
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throw new Error('Parser rule not found: ' + name); |
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} |
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if (isFunction(fn)) { |
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this.rules[index].fn = fn; |
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if (altNames) { |
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this.rules[index].alt = altNames; |
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} |
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} else { |
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this.rules = this.rules.slice(0, index).concat(this.rules.slice(index + 1)); |
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} |
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this.compile(); |
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}; |
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// Add function to parser chain before one with given name.
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// Or add to start, if name not defined
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//
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Ruler.prototype.before = function (name, fn, altNames) { |
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var index; |
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if (isFunction(name)) { |
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altNames = fn; |
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fn = name; |
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name = ''; |
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} |
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if (!name) { |
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this.rules.unshift({ |
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name: functionName(fn), |
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fn: fn, |
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alt: altNames || [] |
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}); |
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} else { |
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index = this.find(name); |
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if (index === -1) { |
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throw new Error('Parser rule not found: ' + name); |
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} |
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this.rules.splice(index, 0, fn); |
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} |
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this.compile(); |
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}; |
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// Add function to parser chain after one with given name.
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// Or add to end, if name not defined
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//
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Ruler.prototype.after = function (name, fn, altNames) { |
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var index; |
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if (isFunction(name)) { |
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altNames = fn; |
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fn = name; |
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name = ''; |
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} |
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if (!name) { |
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this.rules.push({ |
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name: functionName(fn), |
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fn: fn, |
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alt: altNames || [] |
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}); |
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} else { |
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index = this.find(name); |
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if (index === -1) { |
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throw new Error('Parser rule not found: ' + name); |
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} |
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this.rules.splice(index + 1, 0, fn); |
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} |
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this.compile(); |
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}; |
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// Get rules list as array of functions. By default returns main chain
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//
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Ruler.prototype.getRules = function (chainName) { |
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var result = []; |
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if (!chainName) { |
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this.rules.forEach(function (rule) { |
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result.push(rule.fn); |
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}); |
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return result; |
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} |
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this.rules.forEach(function (rule) { |
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if (rule.alt.indexOf(chainName) >= 0) { |
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result.push(rule.fn); |
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} |
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}); |
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return result; |
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}; |
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module.exports = Ruler; |
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