Text::Indent - simple indentation of text shared among modules
In your main program:
use Text::Indent;
my $indent = Text::Indent->new;
$indent->spaces(2);
In a module to produce indented output:
use Text::Indent;
my $indent = Text::Indent->instance;
$indent->increase;
print $indent->indent("this will be indented two spaces");
$indent->increase(2);
print $indent->indent("this will be indented six spaces");
$indent->decrease(3);
Text::Indent is designed for use in programs which need to produce output with multiple levels of indent when the source of the output comes from different modules that know nothing about each other.
For example take module A, whose output includes the indented output of module B. Module B can also produce output directly, so it falls to module B to know whether it should indent it's output or not depending on it's calling context.
Text::Indent allows programs and modules to cooperate to choose an appropriate indent level that is shared within the program context. In the above example, module A would increase the indent level prior to calling the output routines of module B. Module B would simply use the Text::Indent instance confident that if it were being called directly no indent would be applied but if module A was calling it then it's output would be indented one level.
The constructor for Text::Indent should only be called once by the main program using modules that produce indented text. Modules which wish to produce indented text should use the instance accessor described below.
To construct a new Text::Indent object, call the new method, passing one or more of the following parameters as a hash:
-
Spaces
the number of spaces to used for each level of indentation. Defaults to 2.
-
SpaceChar
the character to be used for indentation. Defaults to a space (ASCII 32)
-
Level
The initial indentation level to set. Defaults to 0.
-
AddNewLine
Whether the indent method should automatically add a newline to the input arguments. Defaults to TRUE.
-
Instance
Whether the newly constructed Text::Indent object should become the new singleton instance returned by the instance accessor. Defaults to TRUE.
The instance accessor is designed to be used by modules wishing to produce indented output. If the instance already exists (as will be the case if the main program using the module constructed a Text::Indent object) then both the program and the module will use the same indentation scheme.
If the instance does not exist yet, the instance accessor dispatches it's arguments to the constructor. As such, any of the parameters that the constructor takes may also be passed to the instance accessor. Be mindful that if the instance does exist, any parameters passed to the instance accessor are ignored.
This method increases the level of indentation by $how_many levels. If not provided, $how_many defaults to 1.
This method decreases the level of indentation by $how_many levels. If not provided, $how_many defaults to 1.
This method resets the level of indentation to 0. It is functionally equivalent to $indent->level(0).
This is the primary workhorse method of Text::Indent. It takes a list of arguments to be indented and returns the indented string.
The string returned is composed of the following list:
- the 'space' character repeated x times, where x is the number of spaces multiplied by the indent level.
- the stringification of arguments passed to the method (note that this means that list arguments will have spaces inserted in between them).
- a newline if the 'add_newline' attribute of the Text::Indent object is set.
If the indent level drops is a negative value, no indent is applied.
Gets or sets the number of spaces used for each indent level.
Gets or sets the character used for indentation.
Gets or sets the current indent level.
Gets or sets the boolean attribute that determines if the indent method tacks a newline onto it's arguments.
In the main program producing indented output:
use Text::Indent;
use Bar;
my $bar = Bar->new(...);
my $i = Text::Indent->new( Level => 1 );
print $i->indent("foo");
$i->increase;
print $bar->display;
$i->decrease;
print $i->indent("baz");
$i->reset;
print $i->indent("gzonk");
In Bar.pm:
package Bar;
use Text::Indent;
sub display
{
my $i = Text::Indent->instance;
return $i->indent("bar");
}
The output from the preceding example would be (> indicates the left edge of output and is for illustrative purposes only):
> foo
> bar
> baz
>gzonk
James FitzGibbon, <[email protected]>
Copyright (c) 2003-10 James FitzGibbon. All Rights Reserved.
This module is free software; you may use it under the same terms as Perl itself.
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