parse0x  Artifact Content

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Wiki page [parse0x] by stephan 2008-05-23 22:04:51.
D 2008-05-23T22:04:51
L parse0x
P 250ec29bc962ab90b06d77bda06af135739e5c95
U stephan
W 3627
<center><h1>parse0x: C++0x parser generator toolkit</h1></center>

<center><em>"Online since May 2008!"</em></center>

parse0x is an <em>experimental</em> parser toolkit for C++0x-compliant
C++ compilers, conceptually based very much on
[http://code.google.com/p/pegtl|Dr. Colin Hirsch's PEGTL library],
but stripped of the error reporting facilities that library has.
(This makes it much smaller and somewhat easier to extend, but also not terribly
useful for tracking parsing errors.) It is similar to libraries like
[http://spirit.sf.net|Boost.Spirit] but is much, much smaller in
scope. It requires C++0x support, which is currently only available
[http://gcc.gnu.org/projects/cxx0x.html|in beta form]. Try [http://gcc.gnu.org/gcc-4.3/|gcc 4.3].

parse0x is believed to conform to the rules of Parsing Expression Grammars (PEGs), as
detailed on this 
[http://en.wikipedia.org/wiki/Parsing_expression_grammar|Wikipedia page about PEGs]
(though the formalities of it are admittedly over my head).

This package's home page is:

[http://wanderinghorse.net/computing/parse0x]

<h2>License</h2>

This source code is released into the Public Domain by its author,
Stephan Beal ([http://wanderinghorse.net/home/stephan/]). That is, you may
take it and use it for any purpose whatsoever, commercial or otherwise.

<h2>Examples</h2>

The source tree comes with a test app (test.cpp) which shows how to
do things like parse IP addresses, string literals, and various numeric
types. There is also that most classic of parsing examples, a calculator.

Aside from the example code we have
[IntroToParse0x|a very-much-unfinished introduction to parse0x]
and [RulesOverview|an overview of the built-in parsing rules].

<h2>Features</h2>

<ul>
<li>Allows creation of parsers using Rules, which are
small classes which implement string-matching rules. Rules
can be combined to create parsers of nearly arbitrary
complexity. Rules have no local state and are never instantiated,
so they're memory-light.</li>
<li>There are no separate tokenization and parse phases - they're
combined into a single phase.</li>
<li>Validating-only parsers (that is, without any client-side actions)
can normally be implemented using only typedefs or empty structs
which inherit other rules.</li>
<li>Actions can be tied to any Rules, to handle text a Rule matches.</li>
<li>Passes a client-defined State type to Rules and Actions, so that
custom Rules/Actions can manipulate client-side data during the parsing
process.</li>
<li>A small header-only implementation. The whole core library is implemented
in a single header file, plus some optional headers are included for handling
some common parsing cases (e.g. quoted strings and ipv4 addresses). The core implementation is trivial, thanks to C++0x's variadic templates feature.</li>
<li>Fairly easy to use, at least if one is familiar with template-based
programing and writing parsers.</li>
</ul>

<h2>Misfeatures</h2>

<ul>
<li>Requires C++0x features, which has only limited support in the
newest compilers.</li>
<li>Currently provides no way of reporting where/why a parsing error
occurs. That is, a parse either fails or succeeds, but if it fails
there's no way to know why without adding additional instrumentation
to the parser.</li>
<li>Only works on std::string input, meaning that when reading
from streams you must buffer the whole stream into a string first.</li>
<li>Won't work with binary data, as it relies on a null character to
mark eof.</li>
</ul>



<h2>Download</h2>

See the [download|downloads page].

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