Parsing PHP in Go

by codezero • 12 years ago

143 38 12 years ago

jamesmoss• 12 years ago

Are there any numbers on performance vs php itself?

RossM• 12 years ago

It's not an interpreter - it parses PHP code into an abstract-syntax-tree (list of entities like open-if, variable, assignment, etc).

themartorana• 12 years ago

But with a transpiler, it could become an IL to PHP compilation via Go...?

Not that it would be faster or better than say, HHVM or any other of a number of compilers for PHP [1] but my knowledge of that space is quite limited.

[1] http://stackoverflow.com/questions/1408417/can-you-compile-p...

8ig8• 12 years ago

And here's a PHP parser written in PHP...

https://github.com/nikic/PHP-Parser

DigitalSea• 12 years ago

^ Wow is all I have to say. Solving PHP's grammatical syntax issues alone is a big thing, I commend efforts like this, it seems to work pretty well too (based on playing around with it for a few minutes).

TazeTSchnitzel3• 12 years ago

Unlike the OP, Nikita's PHP parser is actually used for a lot of things. He wrote a script to detect code broken by syntax changes in the next version of PHP, for example.

Anthony Ferrara used it to implement PHP in PHP: https://github.com/ircmaxell/PHPPHP

girvo3• 12 years ago

nikic and Anthony are some of my favourite PHP developers. The stuff that people have been doing in PHP, what with HHVM and Hack and the PSR standards and Composer/Packagist, etc etc. is just amazing!

xmattus• 12 years ago

Now we just need a Go parser written in PHP, for obvious reasons.

aikah• 12 years ago

what about a Go compiler written in Go? is it bootstraped already?

shanemhansen• 12 years ago

Go isn't bootstrapped, but there are parsers for go written in go in the stdlib. http://golang.org/pkg/go/ast/

artursapek• 12 years ago

They're working on it

kyrra• 12 years ago

It's being worked on for Go 1.4 (scheduled to release in December). It's the primary feature they want to get done for that release. There was a talk about in back in May[0]. rcs is working on c2go to convert the existing compiler to Go[1][2].

[0] http://www.confreaks.com/videos/3432-gophercon2014-go-from-c...

[1] https://code.google.com/p/rsc/source/list

[2] https://code.google.com/p/rsc/source/browse/#hg%2Fc2go

ahmett• 12 years ago

Please don't make a PHP transpiler. :(

debaserab2• 12 years ago

Why not?

This could be a crucial tool for companies backporting legacy PHP code into a new language.

UnoriginalGuy• 12 years ago

I agree with you (that it could be an important tool).

However I will say that the VB6->VB.Net transpiler which Microsoft produced (and clearly spent significant amounts of effort on) was pretty terrible. And that is one of the most "complete" transpilers I know of...

The problem is that for a transpiler to produce "good" output code it needs to have a deep understanding of both context but also intent. This is particularly important when converting from one language to another with slightly different underlying concepts (like VB5-6 Vs. VB.Net). Without that understanding it just produces spaghetti code, that will technically compile (*although often it didn't in the VB6->VB.net example) but is unmaintable.

I liken it to Microsoft Word's HTML engine. Word can produce websites, and those websites technically looked correct in most browsers, but they became an unmaintainable mess in the medium to long term. A lot of transpilers have the same issue.

The best thing I can say about transpilers is that they're very good for a starting point (assume 100% refactoring anyway) and converting simplistic data storage vehicles (e.g. classes with tons of constants).

TazeTSchnitzel3• 12 years ago

Well, Facebook made one (HipHop) and ended up with 1GB executables.

jamescun• 12 years ago

For those interested:

Ruby in Go: https://github.com/grubby/grubby

Javascript in Go: https://github.com/robertkrimen/otto

tjarratt2• 12 years ago

Woah, I'm pretty stoked to see someone link to my ruby implementation (neé Grubby).

It seems like the authors of Golang believe that a lot of problems with languages (refactoring, updating code to work with new libraries / versions, etc) can be solved as parsing problems. Hence, Golang has a lot of good tools for parsing text.

They even ported yacc to Go (via Plan9). http://golang.org/cmd/yacc/

pjmlp3• 12 years ago

Such as? Do you mean the Go standard libraries for Go code?

Yacc clones exit for almost every language out there, and there are better ways to do parsing than yacc with its stone age error reporting.

ck2• 12 years ago

PHP has to be one of the most transpiled languages.

C++ (well Hack->C++), .NET, Java, Python and now Go (probably others).

All in various states of incompleteness, though HHVM isn't going away anytime soon.

dubcanada• 12 years ago

Javascript has it's fair share of transpiledness.

benaiah• 12 years ago

Usually JS is the compilation target, not the language being compiled, though.

andrewchambers2• 12 years ago

Go is pretty nice for parser/compiler applications because it is fast and the runtime doesn't take too long to startup.

pjmlp3• 12 years ago

ML languages are way better, specially given sum types and pattern matching.

andrewchambers2• 12 years ago

I agree for tree manipulation - I don't necessarily agree for writing recursive descent parsers.

But I admit, I read the Ocaml and haskell compilers source code, and it was pretty nice.

padator• 12 years ago

Parsing PHP in ocaml: https://github.com/facebook/pfff

try ./pfff -dump_php /path/to/file.php

VeejayRampay• 12 years ago

Parsing, lexing and the general task of writing compilers is such a breeze in OCaml. I remember when I was in college, one of our year projects was to write a small compiler for a subset of postscript using ocamllex and ocamlyacc, couldn't believe how nice and natural it felt. What a great language.

pbiggar• 12 years ago

I worked on a PHP compiler: http://phpcompiler.org. Although it only supports PHP 5.2, it has a really nice parser, which had a lot of work put into it (a ton of edge cases in particular).

It's not in Go, but it does a lot of the interesting things you asked about: static analysis, dead code elimination, transpiling. It also compiles to (pretty poor) C code.

For static analysis, there's a lot to do. Here's my PhD on the topic: http://paulbiggar.com/research/#phd-dissertation

I worked on this for about 4 years, and if my experience is indicative of working on PHP compilers is general, you have a lot of fun, and a massive amount of frustration in front of you.

girvo3• 12 years ago

Since scrutinizer-ci took their interesting "PHP-analyser" private I've been looking for a better static analysis tool for PHP that I can contribute to. HPHPc is alright in HHVM but learning OCaml is slowing me down, so I'm definitely going to take a look at your compiler! Well done :)

fabriceleal• 12 years ago

Personally I would be a lot more interested in a good platform for writing static analysis tools. I believe the community in general would take a more immediate benefit (and what a benefit!...) from this than from a lone PHP to Go transpiler.

kackontent• 12 years ago

How performant is this or other similar projects (pfff, PHP-Parser)? Are any of them a viable option to use for a base of a improved support for PHP in text editors (say vim, st, atom)?

Parsing PHP in Go

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