Imager::Expr::Assem

Section: User Contributed Perl Documentation (3)
Updated: 2008-03-29
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NAME

  Imager::Expr::Assem - an assembler for producing code for the Imager
  register machine

 

SYNOPSIS

  use Imager::Expr::Assem;
  my $expr = Imager::Expr->new(assem=>'...', ...)

 

DESCRIPTION

This module is a simple Imager::Expr compiler that compiles a low-level language that has a nearly 1-to-1 relationship to the internal representation used for compiled regmach code.  

Syntax

Each line can contain multiple statements separated by semi-colons.

Anything after '#' in a line is ignored.

Types of statements:

variable definition
"var" name:type

defines variable name to have type, which can be any of 'n' or 'num' for a numeric type or 'pixel', 'p' or 'c' for a pixel or color type.

Variable names cannot include whitespace.

operators
Operators can be split into 3 basic types, those that have a result value, those that don't and the null operator, eg. jump has no value.

The format for operators that return a value is typically:

result = operator operand ...

and for those that don't return a value:

operator operand

where operator is any valid regmach operator, result is any variable defined with "var", and operands are variables, constants or literals, or for jump operators, labels.

The set operator can be simplified to:

result = operator

All operators maybe preceded by a label, which is any non-whitespace text immediately followed by a colon (':').

 

BUGS

Note that the current optimizer may produce incorrect optimization for your code, fortunately the optimizer will disable itself if you include any jump operator in your code. A single jump to anywhere after your final ret operator can be used to disable the optimizer without slowing down your code.

There's currently no high-level code generation that can generate code with loops or real conditions.  

SEE ALSO

Imager(3), transform.perl, regmach.c  

AUTHOR

Tony Cook <tony@develop-help.com>


 

Index

NAME
SYNOPSIS
DESCRIPTION
Syntax
BUGS
SEE ALSO
AUTHOR

linux.jgfs.net manual pages