Python中的安全表达式解析器 [英] Safe expression parser in Python

问题描述

如何允许用户以安全的方式执行数学表达式? 我需要编写一个完整的解析器吗?

How can I allow users to execute mathematical expressions in a safe way? Do I need to write a full parser?

是否有类似 ast.literal_eval()之类的东西，但对于表情?

Is there something like ast.literal_eval(), but for expressions?

推荐答案

剖析示例"页面列出了几个表达式解析器:

The Pyparsing examples page lists several expression parsers:

http://pyparsing.wikispaces.com/file/view/fourFn.py -使用pyparsing的常规算术中缀表示法解析器/求值器实现(尽管它的名称是5函数算术，再加上一些trig函数)

http://pyparsing.wikispaces.com/file/view/fourFn.py - A conventional arithmetic infix notation parser/evaluator implementation using pyparsing (despite its name, this actually does 5-function arithmetic, plus several trig functions)

http://pyparsing.wikispaces.com/file/view/simpleBool.py -使用pyparsing辅助方法operatorPrecedence的布尔值中缀表示法解析器/评估器，它简化了中缀运算符表示法的定义

http://pyparsing.wikispaces.com/file/view/simpleBool.py - A boolean infix notation parser/evaluator, using a pyparsing helper method operatorPrecedence, which simplifies the definition of infix operator notations

http://pyparsing.wikispaces.com/file/view/simpleArith.py http://pyparsing.wikispaces.com/file/view/eval_arith.py - 一对使用operatorPrecedence重铸fourFn.py的示例.第一个仅解析并返回一个解析树，第二个添加评估逻辑.

http://pyparsing.wikispaces.com/file/view/simpleArith.py http://pyparsing.wikispaces.com/file/view/eval_arith.py - A pair of examples recasting fourFn.py using operatorPrecedence. The first just parses and returns a parse tree, the second adds evaluation logic.

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