NAME
Text::Vpp - Perl extension for a versatile text pre-processor
SYNOPSIS
use Text::Vpp ;
$fin = Text::Vpp-> new('input_file_name') ;
$fin->setVar('one_variable_name' => 'value_one',
'another_variable_name' => 'value_two') ;
$res = $fin -> substitute ;
print "Result is : \n\n",join("\n",@$res) ,"\n";DESCRIPTION
This class enables to preprocess a file a bit like cpp.
First you create a Vpp object passing the name of the file to process, then you call setvar() to set the variables you need.
Finally you call substitute on the Vpp object.
NON-DESCRIPTION
Note that it's not designed to replace the well known cpp. Note also that if you think of using it to pre-process a perl script, you're likely to shoot yourself in the foot. Perl has a lot of built-in mechanism so that a pre-processor is not necessary.
INPUT FILE SYNTAX
Comments
All lines beginning with '#' are skipped. (May be changed with setCommentChar())
in-line eval
Lines beginning with '@EVAL' (@ being pompously named the 'action char') are evaluated as small perl script.
When setActionChar() is called with '#' as a parameter, Vpp doesn't skip lines beginning with '#'. In this case, there's no comment possible.
Multi-line input
Line ending with \ are concatenated with the following line.
Variables substitution
You can specify in your text varaibles beginning with $ (like in perl). These variables can be set either by the setVar() method or by the "eval" capability of Vpp (See below).
Setting variables
Line beginning by @ are "evaled" using variables defined by setVar(). You can use only scalar variables. This way, you can also define variables in your text which can be used later.
Conditional statements
Text::Vpp understands @IF, @ELSIF, @ENDIF,and so on. @INCLUDES and @IF can be nested.
@IF and @ELSIF are followed by a string which will be evaled using the variable you defined (either with setVar() or in the text).
Inclusion
Text::Vpp understands @INCLUDE
Constructor
new(file_name, optional_var_hash_ref, optional_action_char)
Create the file object. The second parameter can be a hash containing all variables needed for the substitute method.
Methods
substitute([output_file])
Perform the substitute, inclusion, and so on and write the result in "output_file". Returns 1 on completion, 0 in case of an error.
If output_file is not specified this function store the subtitution result in an internal variable. The result can be retrieved with getText()
getText()
Returns an array ref containing the result.
getError()
Returns an array ref containing the errors.
setVar( key1=> value1, key2 => value2 ,...) or setVar(hash_ref)
Declare variables for the substitute. Note that calling this function clobbers previously stored values.
setActionChar(char)
Enables the user to use another char as action char. (default @)
Example: setActionChar('#') will enable Vpp to understand #include, #ifdef ..
setCommentChar(char)
Enables the user to use another char as comment char. (default #)
AUTHOR
Dominique Dumont Dominique_Dumont@grenoble.hp.com
Copyright (c) 1996 Dominique Dumont. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
VERSION
Version 0.1
SEE ALSO
perl(1),Text::Template(3).