Text::Sprintf::Named - sprintf-like function with named conversions


version 0.0405


    use Text::Sprintf::Named;

    my $formatter =
            {fmt => "Hello %(name)s! Today is %(day)s!"}

    # Returns "Hello Ayeleth! Today is Sunday!"
    $formatter->format({args => {'name' => "Ayeleth", 'day' => "Sunday"}});

    # Returns "Hello John! Today is Thursday!"
    $formatter->format({args => {'name' => "John", 'day' => "Thursday"}});

    # Or alternatively using the non-OOP interface:

    use Text::Sprintf::Named qw(named_sprintf);

    # Prints "Hello Sophie!" (and a newline).
    print named_sprintf("Hello %(name)s!\n", { name => 'Sophie' });

    # Same, but with a flattened parameter list (not inside a hash reference)
    print named_sprintf("Hello %(name)s!\n", name => 'Sophie');


Text::Sprintf::Named provides a sprintf equivalent with named conversions. Named conversions are sprintf field specifiers (like "%s" or "%4d") only they are associated with the key of an associative array of parameters. So for example "%(name)s" will emit the 'name' parameter as a string, and "%(num)4d" will emit the 'num' parameter as a variable with a width of 4.


my $formatter = Text::Sprintf::Named->new({fmt => $format})

Creates a new object which formats according to the $format format.

$formatter->format({args => \%bindings})

Returns the formatting string as formatted using the named parameters pointed to by the args parameter.


This method is used to calculate the parameter for the conversion. It can be over-rided by subclasses so it will behave differently. An example can be found in t/02-override-param-retrieval.t where it is used to call the accessors of an object for values.

%args contains:

  • named_params

    The named paramters.

  • name

    The name of the conversion.

named_sprintf($format, {%parameters})

named_sprintf($format, %parameters)

This is a convenience function to directly format a string with the named parameters, which can be specified inside a (non-blessed) hash reference or as a flattened hash. See the synopsis for an example.


Shlomi Fish, ,


The (possibly ad-hoc) regex for matching the optional digits+symbols parameters' prefix of the sprintf conversion was originally written by Bart Lateur (BARTL on CPAN) for his String::Sprintf module.

The syntax was borrowed directly from Python’s "%" operator when used with its dictionaries as the right-hand argument. A quick web search did not yield good documentation about it (and I came with the idea of a named sprintf without knowing that Python had it, only ran into the fact that Python had it by web-searching).


Text::sprintfn is a newer module which only provides a procedural interface that allows one to mix positional and named arguments, with some other interesting features.

String::Formatter is a comprehensive module that allows one to define custom sprintf-like functions (I’m not sure whether it has named conversions). Its license is the GNU General Public Licence version 2 (GPLv2), which is both restrictive, and incompatible with version 3 of the GPL and with many other open-source licenses.

String::Sprintf appears to allow one to provide custom sprintf/printf formats (without providing named conversions).

For the lighter side, there is Acme::StringFormat, which provides a "%" operator to format a string.


Copyright 2006 Shlomi Fish, all rights reserved.

This program is released under the following license: MIT/X11:



The following websites have more information about this module, and may be of help to you. As always, in addition to those websites please use your favorite search engine to discover more resources.

Bugs / Feature Requests

Please report any bugs or feature requests by email to bug-text-sprintf-named at, or through the web interface at You will be automatically notified of any progress on the request by the system.

Source Code

The code is open to the world, and available for you to hack on. Please feel free to browse it and play with it, or whatever. If you want to contribute patches, please send me a diff or prod me to pull from your repository :)

  git clone


Shlomi Fish <>


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.


This software is Copyright (c) 2020 by Shlomi Fish.

This is free software, licensed under:

  The MIT (X11) License