# Overview

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# Boolexp

Boolexp provides "safe" evaluation of boolean expressions for use cases where

eval might be dangerous. Boolexp expressions are context-free and mimic

Python sytax. Only basic math opearations and data structures are provided.

## Instalation

To install Boolexp, change to the directory where setup.py is located and type:

python setup.py install

Requirements:

- Python 2.7
- pyparsing 1.5.0 or later

## Expression Syntax Overview

Basic math operators **,/,+,-* have highest priority

>>> from boolexp import Expression >>> Expression("4 + 4 / 2").evaluate() >>> 6 >>> Expression("( 4 + 4 ) / 2 ").evaluate() >>> 4

Comparsion operators *!=, ==, <, >, <=, >=, in* are next in priority. All

comparsion operators have return type of *boolean*, which can be used

as input for *boolean* operators *and, or, not* with lowest priority.

>>> from boolexp import Expression >>> Expression(2 == 1).evaluate() >>> False >>> Expression("2 * - 2 == - 4").evaluate() >>> True >>> Expression("not 2 == 3").evaluate() >>> True >>> Expression("3 <= 8 and 2 == 5").evaluate() >>> False

### Expresions with with variables

This all would not be much of a fun without posibility to use variables.

Allowed types for variables are *bool,int,float,str,list,dict*

>>> from boolexp import Expression >>> Expression("1 in v").evaluate(dict(v=[1,2])) >>> True >>> Expression("one[1].part == 2").evaluate(dict(one=[1, dict(part=2)], two=1)) >>> True

## Disclaimer

This project is now in a state of proof of concept only, thus far from suitable

for production enviroment.

## License

Copyright (C) 2013, Peter Facka, Lukas Lamper

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

THE SOFTWARE.