基于JavaScript的公式解释器 - 4 【操作符基类型的实现】

操作符优先级定义

文件：OperatorBase.js

// JScript source code var $OperatorPriority = { // Logic "||": 0, "&&": 0, // Compare ">": 1, ">=": 1, "<": 1, "<=": 1, // Logic compute "|": 2, "&": 2, "^": 2, // Mathematic "+": 3, "-": 3, "*": 4, "/": 4, "%": 4, // Func "function": 5, "unary": 6 };

 

操作符类型定义

文件：OperatorBase.js

/***************************** Operator Type *****************************/ function UnknownType(sign, argsNum) { this.DeriveFrom(new Object()); this.set_ClassName("UnknownType"); this._sign = sign; this._requiredArgsNum = argsNum; }; UnknownType.prototype = { get_RequiredArgumentsNum: function() { return this._requiredArgsNum; }, get_Sign: function() { return this._sign; } }; function UnaryType(sign) { this.DeriveFrom(new UnknownType(sign, 1)); this.set_ClassName("UnaryType"); }; function BinaryType(sign) { this.DeriveFrom(new UnknownType(sign, 2)); this.set_ClassName("BinaryType"); }; function ParenthesesType(sign) { this.DeriveFrom(new UnknownType(sign, 1)); this.set_ClassName("ParentthesesType"); }; function FunctionType(name) { this.DeriveFrom(new UnknownType(name, -1)); this.set_ClassName("FunctionType"); };

 

OperatorBase 操作符基类型定义

文件：OperatorBase.js

// ----------- OperatorBase -------------- function OperatorBase() { this.set_ClassName("OperatorBase"); this._type = new UnknownType("undefined", -1); }; OperatorBase.prototype = { // Properties get_Type: function() { return this._type; }, get_Sign: function() { return this._type.get_Sign(); }, set_Sign: function(sign) { this._type._sign = sign; }, get_RequiredArgumentsNum: function() { return this._type.get_RequiredArgumentsNum(); }, get_Priority: function() { if (!(this.IsFunction() || this.IsUnary())) return $OperatorPriority[this.get_Sign()]; else { if (this.IsFunction()) return $OperatorPriority["function"]; else return $OperatorPriority["unary"]; } }, IsPreceding: function(anotherOperator) { if (this.IsUnary()) { if (anotherOperator.IsUnary()) return false; else return true; } else { if (anotherOperator.IsUnary()) return false; else return this.get_Priority() > anotherOperator.get_Priority(); } }, // IsPreceding IsUnary: function() { return $T(this._type) == "UnaryType"; }, IsBinary: function() { return $T(this._type) == "BinaryType"; }, IsFunction: function() { return $T(this._type) == "FunctionType"; }, IsParentheses: function() { return $T(this._type) == "ParenthesesType"; }, Evaluate: function(operandArray) { throw new Exception(this, "Evaluate", "Not implemented"); } // Evaluate };