hiqdev / hoa-compiler
The Hiqdev Hoa\Compiler library.
Requires
- php: >=7.4
- hoa/consistency: ~1.0
- hoa/exception: ~1.0
- hoa/file: ~1.0
- hoa/iterator: ~2.0
- hoa/math: ~1.0
- hoa/protocol: ~1.0
- hoa/regex: ~1.0
- hoa/visitor: ~2.0
Requires (Dev)
- hoa/json: ~2.0
- hoa/test: ~2.0
- phpunit/phpunit: ^9.5
Replaces
- hoa/compiler: ~3.0
This package is auto-updated.
Last update: 2024-10-29 06:46:57 UTC
README
The Hoa project was archived, and no upgrades or patches are neither provided nor accepted by merge requests.
HOA Packages include some code that is Deprecated for PHP 8.0 and PHP 8.1, but we needed these packages to run on modern PHP versions.
What's changed in from?
The changes mainly affected the return data type hinting in methods declaration, access to uninitialized properties.
How to use
We've currently forked the following packages, primarily to make hoa/ruler work with PHP 8.1:
You can simply replace requirements in composer.json from hoa packages to the corresponding forked packages: there is no need to change something in the codebase.If you use someone's package, that requires hoa – simply add forks to your project root composer.json: we have marked forks as a replacement, so composer will install them instead of the original packages.
Versions
We've forked from the latest hoa package versions and bump own versions starting from 1.0.
Testing
Before running the test suites, the development dependencies must be installed:
$ composer install
Then, to run all the test suites:
$ vendor/bin/hoa test:run
For more information, please read the contributor guide.
Quick usage
As a quick overview, we will look at the PP language and the LL(k) compiler compiler.
The PP language
A grammar is constituted by tokens (the units of a word) and rules (please, see the documentation for an introduction to the language theory). The PP language declares tokens with the following construction:
%token [source_namespace:]name value [-> destination_namespace]
The default namespace is default
. The value of a token is represented by a
PCRE. We can skip tokens with the %skip
construction.
As an example, we will take the simplified grammar of the JSON
language. The complete grammar is in the
hoa://Library/Json/Grammar.pp
file. Thus:
%skip space \s
// Scalars.
%token true true
%token false false
%token null null
// Strings.
%token quote_ " -> string
%token string:string [^"]+
%token string:_quote " -> default
// Objects.
%token brace_ {
%token _brace }
// Arrays.
%token bracket_ \[
%token _bracket \]
// Rest.
%token colon :
%token comma ,
%token number \d+
value:
<true> | <false> | <null> | string() | object() | array() | number()
string:
::quote_:: <string> ::_quote::
number:
<number>
#object:
::brace_:: pair() ( ::comma:: pair() )* ::_brace::
#pair:
string() ::colon:: value()
#array:
::bracket_:: value() ( ::comma:: value() )* ::_bracket::
We can see the PP constructions:
rule()
to call a rule;<token>
and::token::
to declare a token;|
for a disjunction;(…)
to group multiple declarations;e?
to say thate
is optional;e+
to say thate
can appear at least 1 time;e*
to say thate
can appear 0 or many times;e{x,y}
to say thate
can appear betweenx
andy
times;#node
to create a node the AST (resulting tree);token[i]
to unify tokens value between them.
Unification is very useful. For example, if we have a token that expresses a quote (simple or double), we could have:
%token quote "|'
%token handle \w+
string:
::quote:: <handle> ::quote::
So, the data "foo"
and 'foo'
will be valid, but also "foo'
and 'foo"
! To
avoid this, we can add a new constraint on token value by unifying them, thus:
string:
::quote[0]:: <handle> ::quote[0]::
All quote[0]
for the rule instance must have the same value. Another example
is the unification of XML tags name.
LL(k) compiler compiler
The Hoa\Compiler\Llk\Llk
class provide helpers to manipulate (load or save) a
compiler. The following code will use the previous grammar to create a compiler,
and we will parse a JSON string. If the parsing succeed, it will produce an AST
(stands for Abstract Syntax Tree) we can visit, for example to dump the AST:
// 1. Load grammar. $compiler = Hoa\Compiler\Llk\Llk::load(new Hoa\File\Read('Json.pp')); // 2. Parse a data. $ast = $compiler->parse('{"foo": true, "bar": [null, 42]}'); // 3. Dump the AST. $dump = new Hoa\Compiler\Visitor\Dump(); echo $dump->visit($ast); /** * Will output: * > #object * > > #pair * > > > token(string, foo) * > > > token(true, true) * > > #pair * > > > token(string, bar) * > > > #array * > > > > token(null, null) * > > > > token(number, 42) */
Pretty simple.
Compiler in CLI
This library proposes a script to parse and apply a visitor on a data with a
specific grammar. Very useful. Moreover, we can use pipe (because
Hoa\File\Read
—please, see the Hoa\File
library— supports 0
as
stdin
), thus:
$ echo '[1, [1, [2, 3], 5], 8]' | hoa compiler:pp Json.pp 0 --visitor dump > #array > > token(number, 1) > > #array > > > token(number, 1) > > > #array > > > > token(number, 2) > > > > token(number, 3) > > > token(number, 5) > > token(number, 8)
You can apply any visitor classes.
Errors
Errors are well-presented:
$ echo '{"foo" true}' | hoa compiler:pp Json.pp 0 --visitor dump Uncaught exception (Hoa\Compiler\Exception\UnexpectedToken): Hoa\Compiler\Llk\Parser::parse(): (0) Unexpected token "true" (true) at line 1 and column 8: {"foo" true} ↑ in hoa://Library/Compiler/Llk/Parser.php at line 1
Samplers
Some algorithms are available to generate data based on a grammar. We will give only one example with the coverage-based generation algorithm that will activate all branches and tokens in the grammar:
$sampler = new Hoa\Compiler\Llk\Sampler\Coverage( // Grammar. Hoa\Compiler\Llk\Llk::load(new Hoa\File\Read('Json.pp')), // Token sampler. new Hoa\Regex\Visitor\Isotropic(new Hoa\Math\Sampler\Random()) ); foreach ($sampler as $i => $data) { echo $i, ' => ', $data, "\n"; } /** * Will output: * 0 => true * 1 => {" )o?bz " : null , " %3W) " : [false, 130 , " 6" ] } * 2 => [{" ny " : true } ] * 3 => {" Ne;[3 " :[ true , true ] , " th: " : true," C[8} " : true } */
Research papers
- Grammar-Based Testing using Realistic Domains in PHP, presented at A-MOST 2012 (Montréal, Canada) (article, presentation, details).
Documentation
The
hack book of Hoa\Compiler
contains
detailed information about how to use this library and how it works.
To generate the documentation locally, execute the following commands:
$ composer require --dev hoa/devtools $ vendor/bin/hoa devtools:documentation --open
More documentation can be found on the project's website: hoa-project.net.
Getting help
There are mainly two ways to get help:
- On the
#hoaproject
IRC channel, - On the forum at users.hoa-project.net.
Contribution
Do you want to contribute? Thanks! A detailed contributor guide explains everything you need to know.
License
Hoa is under the New BSD License (BSD-3-Clause). Please, see
LICENSE
for details.