General::Interpolated(User Contributed Perl DocumentGeneral::Interpolated(3pm)
NAME
Config::General::Interpolated - Parse variables within Config files
SYNOPSIS
use Config::General;
$conf = Config::General->new(
-ConfigFile => 'configfile',
-InterPolateVars => 1
);
DESCRIPTION
This is an internal module which makes it possible to interpolate Perl
style variables in your config file (i.e. $variable or "${variable}").
Normally you don't call it directly.
VARIABLES
Variables can be defined everywhere in the config and can be used
afterwards as the value of an option. Variables cannot be used as keys
or as part of keys.
If you define a variable inside a block or a named block then it is
only visible within this block or within blocks which are defined
inside this block. Well - let's take a look to an example:
# sample config which uses variables
basedir = /opt/ora
user = t_space
sys = unix
<table intern>
instance = INTERN
owner = $user # "t_space"
logdir = $basedir/log # "/opt/ora/log"
sys = macos
<procs>
misc1 = ${sys}_${instance} # macos_INTERN
misc2 = $user # "t_space"
</procs>
</table>
This will result in the following structure:
{
'basedir' => '/opt/ora',
'user' => 't_space'
'sys' => 'unix',
'table' => {
'intern' => {
'sys' => 'macos',
'logdir' => '/opt/ora/log',
'instance' => 'INTERN',
'owner' => 't_space',
'procs' => {
'misc1' => 'macos_INTERN',
'misc2' => 't_space'
}
}
}
As you can see, the variable sys has been defined twice. Inside the
<procs> block a variable ${sys} has been used, which then were
interpolated into the value of sys defined inside the <table> block,
not the sys variable one level above. If sys were not defined inside
the <table> block then the "global" variable sys would have been used
instead with the value of "unix".
Variables inside double quotes will be interpolated, but variables
inside single quotes will not interpolated. This is the same behavior
as you know of Perl itself.
In addition you can surround variable names with curly braces to avoid
misinterpretation by the parser.
NAMING CONVENTIONS
Variable names must:
• start with a US-ASCII letter(a-z or A-Z) or a digit (0-9).
• contain only US-ASCII letter(a-z or A-Z), digits (0-9), the dash
(-)
colon (:), dot (.), underscore (_) and plus (+) characters.
For added clarity variable names can be surrounded by curly braces.
SEE ALSO
Config::General
AUTHORS
Thomas Linden <tlinden |AT| cpan.org>
Autrijus Tang <autrijus@autrijus.org>
Wei-Hon Chen <plasmaball@pchome.com.tw>
COPYRIGHT
Copyright 2001 by Wei-Hon Chen <plasmaball@pchome.com.tw>. Copyright
2002-2022 by Thomas Linden <tlinden |AT| cpan.org>.
This program is free software; you can redistribute it and/or modify it
under the terms of the Artistic License 2.0.
See <http://www.perl.com/perl/misc/Artistic.html>
VERSION
2.16
perl v5.34.0 2022-10-13 General::Interpolated(3pm)
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