PHP.rb: A Ruby to PHP Code Generator
"Will write code that writes code that writes code that writes code for money."
-- Anonymous on comp.lang.lisp
PHP.rb translates Ruby code into PHP code by obtaining the parse
tree for a Ruby expression, transforming that into an abstract
syntax tree (AST) compatible with PHP, and then generating valid PHP
code as the final output.
Usage
require 'php'
Generating PHP code using a Ruby block
PHP.generate returns the translated AST for a given Ruby block. The AST
can be turned into runnable PHP code by calling the #to_s method on the
resulting PHP::Program instance.
PHP.generate { echo "Hello, world!\n" } #=> PHP::Program(...)
Evaluating generated PHP on the fly
PHP.eval translates Ruby code into PHP utilizing PHP.generate and then
executes it using the php executable (which must be available in
ENV['PATH']).
PHP.eval { echo "Hello, world!\n" }
Checking the available PHP version
PHP.version utilizes PHP.eval to obtain the currently available PHP
version (if any).
PHP.version #=> "5.3.1"
Examples
The following snippets demonstrate the PHP output generated by PHP.rb for
the given Ruby code. Look in the doc/examples/ directory for
runnable Ruby scripts containing many of these examples.
Function definitions
def unid
return md5(uniqid(mt_rand, true))
end
<?php
function unid() {
return md5(uniqid(mt_rand(), TRUE));
}
String construction
$url = "#{$scheme}://#{$host}:#{$port}" << $path
<?php
$url = $scheme . "://" . $host . ":" . $port . $path;
foreach loops (1)
for $fruit in ['apple', 'banana', 'cranberry']
echo "#{$fruit}\n"
end
<?php
foreach (array("apple", "banana", "cranberry") as $fruit) {
echo($fruit . "\n");
}
foreach loops (2)
for $key, $value in {'a' => 1, 'b' => 2, 'c' => 3}
echo "#{$key} => #{$value}\n"
end
<?php
foreach (array("a" => 1, "b" => 2, "c" => 3) as $key => $value) {
echo($key . " => " . $value . "\n");
}
while loops
$result = mysql_query("SELECT name FROM user")
while $row = mysql_fetch_assoc($result)
echo "User.name = #{$row['name']}\n"
end
<?php
$result = mysql_query("SELECT name FROM user");
while ($row = mysql_fetch_assoc($result)) {
echo("User.name = " . $row["name"] . "\n");
}
Reference
The following cheat sheet demonstrates the PHP output generated for various
types of Ruby expressions. The rows marked with an asterisk, (*), may have
special semantics that need to be taken into account.
Literals
Ruby input | PHP output
-------------------------------------|--------------------------------------
nil | NULL
false | FALSE
true | TRUE
42 | 42
3.1415 | 3.1415
"Hello, world!" | "Hello, world!"
"<#{$url}>" | "<" . $url . ">"
/a-z/ | '/a-z/'
(1..10) | range(1, 10)
(1...10) | range(1, 9)
[] | array()
[1, 2, 3] | array(1, 2, 3)
{} | array()
{"a" => 1, "b" => 2, "c" => 3} | array("a" => 1, "b" => 2, "c" => 3)
Variables
Ruby input | PHP output
-------------------------------------|--------------------------------------
$foo | $foo
$foo = 123 | $foo = 123
Functions
Ruby input | PHP output
-------------------------------------|--------------------------------------
lambda { |$x, $y| } | function($x, $y) {}
def foo(x, y); end | function foo($x, $y) {}
time | time()
time() | time()
Methods
Ruby input | PHP output
-------------------------------------|--------------------------------------
$array[$index] | $array[$index]
$object[:property] | $object->property (*)
$object.method | $object->method()
String operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
$a << $b | $a . $b (*)
Arithmetic operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
-$a | -$a
$a + $b | $a + $b
$a - $b | $a - $b
$a * $b | $a * $b
$a / $b | $a / $b
$a % $b | $a % $b
Assignment operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
$a = $b | $a = $b
Bitwise operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
~$a | ~$a
$a & $b | $a & $b
$a | $b | $a | $b
$a ^ $b | $a ^ $b
Comparison operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
$a == $b | $a == $b
$a === $b | $a === $b (*)
$a != $b | $a != $b
$a < $b | $a < $b
$a > $b | $a > $b
$a <= $b | $a <= $b
$a >= $b | $a >= $b
Execution operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
`hostname` | `hostname`
Logical operators
Ruby input | PHP output
-------------------------------------|--------------------------------------
!$a | !$a
$a and $b | $a && $b
$a && $b | $a && $b
$a or $b | $a || $b
$a || $b | $a || $b
Control structures
Ruby input | PHP output
-------------------------------------|--------------------------------------
... if true | if (TRUE) { ... }
if true then ... else ... end | if (TRUE) { ... } else { ... }
... unless true | if (!TRUE) { ... }
unless true then ... else ... end | if (!TRUE) { ... } else { ... }
while $x; ...; end | while ($x) { ... }
until $x; ...; end | while (!$x) { ... }
for $x in $y; ...; end | foreach ($y as $x) { ... }
for $k, $v in $z; ...; end | foreach ($z as $k => $v) { ... }
return | return
return $x | return $x
Classes and objects
Ruby input | PHP output
-------------------------------------|--------------------------------------
MyClass.new | new MyClass
MyClass.new($options) | new MyClass($options)
MyClass.new("abc" => 123) | new MyClass(array("abc" => 123))
Regular expressions
Ruby input | PHP output
-------------------------------------|--------------------------------------
/^\d+$/ =~ "123" | preg_match('/^\d+$/', "123")
/^\d+$/ !~ "123" | !preg_match('/^\d+$/', "123")
"123" =~ /^\d+$/ | preg_match('/^\d+$/', "123")
"123" !~ /^\d+$/ | !preg_match('/^\d+$/', "123")
$pattern =~ $string | preg_match($pattern, $string)
$pattern !~ $string | !preg_match($pattern, $string)
Limitations
This is not a Ruby runtime
PHP.rb is not Ruby for PHP, merely PHP for Ruby.
You don't have the Ruby standard library available in your generated code.
To generate runnable PHP code, you can't expect e.g. "foobar".size to
work, but must rather say strlen("foobar").
Method calls vs property access
Ruby method calls, e.g. $user.name, are in principle ambiguous when
translated into PHP, because they could resolve into either a property
access as in $user->name or a method call as in $user->name().
Therefore PHP.rb defines $user.name to be equivalent to the latter (the
method call), and defines the syntax $user[:name] to be equivalent to the
former (the property access).
Note that this does not conflict with array subscript access since Ruby symbol objects have no semantic equivalent in PHP.
Documentation
Methods
- {PHP.eval}
- {PHP.exec}
- {PHP.dump}
- {PHP.generate}
- {PHP.version}
Classes
- {PHP::Generator}
- {PHP::Program}
- {PHP::Expression}
Dependencies
- Open4 (>= 1.0.1)
- ParseTree (>= 3.0.4)
- RubyParser (>= 2.0.4)
- SexpProcessor (>= 3.0.3)
Installation
The recommended installation method is via RubyGems. To install the latest official release from Gemcutter, do:
% [sudo] gem install php
Download
To get a local working copy of the development repository, do:
% git clone git://github.com/bendiken/php.git
Alternatively, you can download the latest development version as a tarball as follows:
% wget http://github.com/bendiken/php/tarball/master
Resources
- http://php.rubyforge.org/
- http://github.com/bendiken/php
- http://gemcutter.org/gems/php
- http://rubyforge.org/projects/php/
- http://raa.ruby-lang.org/project/php/
Authors
License
PHP.rb is free and unencumbered public domain software. For more
information, see http://unlicense.org/ or the accompanying UNLICENSE file.