Library like pyparsing for PHP

Question

I would like to know: is there something like pyparsing (a recursive descent parser) for PHP?
I already looked for it, but it seems no one did it yet. I hope I am wrong.

Thank you in advance.

Custom nested expressions with different enclosing characters. Not a simple thing with Regex :-( — Donovan, Sep 17 '11 at 22:07
@stereofrog: that project seems to be dead, but I'll have a look. Thank you. — Donovan, Sep 17 '11 at 22:08
@Alberteddu: Could you give an example / a formal grammar? Depending on what exactly it is, it might be better to use a recursive regex (you can do recursion in regex and it's easy) or a hand written regex lexer and parser or a parser generator. Depends on the complexity of the grammar. — NikiC, Sep 18 '11 at 09:09

NikiC · Accepted Answer · 2011-09-18T09:30:16.440

I don't know any maintained parser generators written in PHP. But there are parser generators written in other languages with PHP as a target language. One I have personally used is kmyacc. There is a PHP and Windows compatible fork of it. The grammar for it is written in yacc format and can be compiled to PHP using this command:

kmyacc -l -m %PARSER_PROTOTYPE_FILE% -p %NAME% %GRAMMAR_FILE%

Kmyacc already comes with a procedural parser prototype file for PHP, but I personally use a modified version of an OOP based prototype.

As an example: This grammar get's compiled into this parser. (Note that the grammar is huge, that's why the generated parser has two and a half thousand lines. A "normal" grammar would obviously be far smaller.)

Thi is very interesting. I'm going to take a look. Thanks a lot (obviously if that's what I need I'll check as answered). — Donovan, Sep 18 '11 at 10:46

score 2 · Answer 2 · edited May 23 '17 at 12:29

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If all you need to parse are "custom expressions", you can probably code a recursive descent parser by hand fairly easily, if you have already written down your grammar.

See this SO answer for details: Is there an alternative for flex/bison that is usable on 8-bit embedded systems?

edited May 23 '17 at 12:29

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answered Sep 18 '11 at 10:55

Ira Baxter

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Hehe, always bumping into you on parsing questions :) – NikiC Sep 18 '11 at 11:37
@NikiC: Bad side effect of doing that for a living for 40 years :-} – Ira Baxter Sep 18 '11 at 14:44

score 0 · Answer 3 · answered Sep 15 '11 at 20:54

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You can try this:

http://pyparsing.wikispaces.com/message/view/home/41772107

answered Sep 15 '11 at 20:54

dbers

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Thank you. I did find this but it's not what I need. I'll have to parse complex strings – Donovan Sep 17 '11 at 22:08
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Pyparsing is no longer hosted on wikispaces.com. Go to https://github.com/pyparsing/pyparsing – PaulMcG Aug 27 '18 at 12:44

Library like pyparsing for PHP

3 Answers3