Parrot intermediate representation

<h2 id="overview">Overview</h2>
<p>PIR provides a set of abstractions that allow the programmer to ignore certain redundancies in the Parrot <a href="/facts/Bytecode/EPkMFR7M">bytecode</a> and quickly write code that adheres to the complexities of Parrot, such as the calling conventions.
</p>
<h3>Abstractions</h3>
<p>PIR provides both type abstraction and <a href="/facts/Type_polymorphism/S3cCKsVT">polymorphism</a> to some degree. For example, the "+" operator can be used with int, num or both:
</p>
 .local int a
 .local num b
 a = 1
 b = 1.1
 .local num c
 c = a + b

<h3>Calling conventions</h3>
<p>The calling conventions in Parrot are complex, but all of that complexity can be hidden by using PIR directives:
</p>
 .sub foo
  .param int a
  .param int b
  .local int tmp
  tmp = a + b
  .return (tmp)
 .end

<p>Each of the directives prefixed with a "." expands to the required Parrot bytecode, but does not directly represent any fundamental Parrot operation.
</p>
<h2 id="example">Example</h2>
<p>The <a href="/facts/Hello_world_program/vLn0jLlL">hello world program</a> in PIR is
</p>
 .sub hello :main
  print "Hello world!\n"
 .end

<p>If the program is saved as <i>hello.pir</i>, it can be <a href="/facts/Compiler/WNfCDFJe">compiled</a> and <a href="/facts/Execution_(computing)/1fyfGMFm">executed</a> with this command: parrot hello.pir
</p>
<h2 id="external-links">External links</h2>
<ul><li><a href="http://docs.parrot.org/parrot/latest/html/docs/user/pir/intro.pod.html">Writing PIR</a></li>
<li><a href="http://www.parrot.org/dev/examples/pir">PIR examples</a></li></ul>

Parrot intermediate representation open-in-new

Parrot intermediate representation