PHP中的动态逻辑表达式解析/评估? [英] Dynamic logical expression parsing/evaluation in PHP?

问题描述

我需要评估一些PHP页面上任意复杂度的用户定义逻辑表达式.假设表单字段是主要变量，则需要:

I have a need to evaluate user-defined logical expressions of arbitrary complexity on some PHP pages. Assuming that form fields are the primary variables, it would need to:

• 用变量"代替表格 字段值；
• 处理比较运算符， 至少==，<，< =，> =和>由 符号，名称(例如eq，lt，le，ge，gt 分别)；
• 不处理布尔运算符，和，或或 可能是按名称，符号(例如，！， && ;, ||和^^)；
• 处理字符串的文字值 和数字；
• 为纯文本而非XML(例如名字" ==''或姓氏=='');和
• 表现合理.

• substitute"varibles" for form fields values;
• handle comparison operators, minimally ==, <, <=, >= and > by symbol, name (eg eq, lt, le, ge, gt respectively);
• handle boolean operators not, and, or and possibly xor by name, symbol (eg !, &&, || and ^^ respectively);
• handle literal values for strings and numbers;
• be plaintext not XML (eg "firstname == '' or lastname == ''); and
• be reasonably performant.

现在，在过去的几年中，我已经编写了递归下降解析器，可以构建表达式树并执行此类操作，但这并不是我要用PHP来完成的任务，因此我希望那里有能够解决的问题至少可以带我去那里.

Now in years gone by I've written recursive descent parsers that could build an expression tree and do this kind of thing but thats not a task I'm relishing in PHP so I'm hoping there are things out there that will at least get me some of the way there.

建议?

推荐答案

检查 create_function ，它会创建来自传递的字符串参数的匿名函数，我不确定它的性能，但是它非常灵活...

Check create_function, it creates an anonymous function from the string parameters passed, I'm not sure about its performance, but it's very flexible...

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