PHPTutorial

Generating PHP parser & usage code

This tutorial will demonstrate how to use the The program interface definition framework to generate a PHP command line parser for your program.

• [Generating PHP parser & usage code](#Generating PHP parser & usage code)
  • [Step 1. Defining the options](#Step 1. Defining the options)
  • [Step 2. Generate parser and program description](#Step 2. Generate parser and program description)
  • [Step 3. Write your program](#Step 3. Write your program)
  • [Step 4. Run!](#Step 4. Run!)
  • [Step 5. Beyond the PHP program](#Step 5. Beyond the PHP program)
    • [Auto complete](#Auto complete)
  • [See also](#See also)

Step 1. Defining the options

The first step is to describe the program options in a XML file. The XML elements have to follow the program interface XML Schema. miniapp.xml

#!xml
<?xml version="1.0" encoding="utf-8"?>
<prg:program version="2.0" xmlns:prg="http://xsd.nore.fr/program">
	<prg:name>miniapp</prg:name>
	<prg:version>1.0</prg:version>
	<prg:options>
		<prg:switch>
			<prg:databinding>
				<prg:variable>displayHelp</prg:variable>
			</prg:databinding>
			<prg:names>
				<prg:long>help</prg:long>
				<prg:short>h</prg:short>
			</prg:names>
		</prg:switch>
		<prg:argument>
			<prg:databinding>
				<prg:variable>arg</prg:variable>
			</prg:databinding>
			<prg:names>
				<prg:long>some-arg</prg:long>
				<prg:short>a</prg:short>
			</prg:names>
		</prg:argument>
	</prg:options>
</prg:program>

You can use any editor to write this file but an XML editor with auto-completion and XML Schema support will greatly increase the writing speed.

Step 2. Generate parser and program description

Using the build-php command line tool

#!bash
${NS_XML_PATH}/ns/sh/build-php.sh --xml-description miniapp.xml --embed --output miniapp-cli.php

This command line will generate [miniapp-cli.php](https://github.com/noresources/ns-xml/wiki/miniapp-cli.php) which will contains

• A copy of the PHP parser classes
• A miniappProgramInfo class, extending ProgramInfo, which is a PHP representation of the XML file.

Step 3. Write your program

Let's write a little and useless PHP program [miniapp.php](https://github.com/noresources/ns-xml/wiki/miniapp.php)

#!php
#!/usr/bin/env php
<?php
#
# The line above will tell the shell to invoke the php interpreter
# so the program can be called directly
# ./miniapp.php arg1 arg2 ...
#
# Without this line, you have to type
# php -f miniapp.php -- arg1 arg2 ...
#
# This line should be removed if the program
# can be called through http SAPI

/*
 * Include the parser program interface definition
 * generated by build-php
 */
require dirname(__FILE__) . "/miniapp-cli.php";

/*
 * Represents the miniapp interface description
 */
$info = new miniappProgramInfo;

/*
 * Create a command line parser
 */
$parser = new Parser($info);

/*
 * Parse all command line arguments except the first (the program path)
 *
 * The returned value is an instance of ProgramResult
 * populated dynamically with the value of miniapp's options
 */
$result = $parser->parse($_SERVER["argv"], 1);

/*
 * Define several display options for program usage
 */
$usage = new UsageFormat;

/*
 * PregramResult redefines the __invoke magic method.
 * This will return TRUE if no error occurs
 */
if (!$result())
{
	// Print all warnings and errors
	foreach ($result->getMessages() as $m)
	{
		echo (" - " . $m . "\n");
	}
	
	/*
	 * Prints a short program usage
	 */
	$usage->format = UsageFormat::SHORT_TEXT;
	echo ($info->usage($usage));
}

/**
 * ProgramResult redefines the __get and __call magic methods
 * to search in its OptionResult array.
 *
 * Thus, OptionResult redefines __invoke to return the value of the option.
 * In this case, a switch will return a boolean to indicates if it was present or not
 *
 * The longer version is
 *  $result["displayHelp"]-isSet
 * or
 *  $result["displayHelp"]-value()
 */
if ($result->displayHelp())
{
	/*
	 * Prints a detailed program usage
	 */
	$usage->format = UsageFormat::DETAILED_TEXT;
	echo ($info->usage($usage));
}

if ($result->arg->isSet)
{
	/*
	 * Here, __invoke returs the option argument value
	 */
	echo ("Value of arg: " . $result->arg() . "\n");
}

?>

Step 4. Run!

#!bash
php -f ./miniapp.php -- --help --some-arg "Bleeeh Blaaah"

You should try to type invalid options or forget the --some-arg argument to see what's happen.

Step 5. Beyond the PHP program

Auto complete

To get a bash auto-completion command file, use the bashcompletion.xsl style sheet to transform the option specification file

#!bash
xsltproc -o miniapp-autocomplete.inc.sh ${NS_XML_PATH}/ns/xsl/program/${SCHEMA_VERSION}/bashcompletion.xsl miniapp.xml

Then, include the generated file in your current environment

#!bash
. miniapp-autocomplete.inc.sh

And try typing

#!bash
./miniapp -<TAB>

The shell will propose...

#!bash
$ ./miniapp -
-a		   -h		   --help	   --some-arg   

See the Bash auto-complete file generation for more details.

See also

• The PHP parser API details
• build-php command line tool usage

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The program interface definition framework