NAME¶
String::Errf - a simple sprintf-like dialect
VERSION¶
version 0.007
SYNOPSIS¶
use String::Errf qw(errf);
print errf "This process was started at %{start}t with %{args;argument}n.\n",
{ start => $^T, args => 0 + @ARGV };
...might print something like:
This process was started at 2010-10-17 14:05:29 with 0 arguments.
DESCRIPTION¶
String::Errf provides "errf", a simple string formatter that works
something like "sprintf". It is implemented using String::Formatter
and Sub::Exporter. Their documentation may be useful in understanding or
extending String::Errf. The "errf" subroutine is only available when
imported. Calling String::Errf::errf will not do what you want.
DIFFERENCES FROM SPRINTF¶
The data passed to "errf" should be organized in a single hashref, not
a list.
Formatting codes require named parameters, and the available codes are
different. See "FORMATTING CODES" below.
As with most String::Formatter formatters, "%" is not a format code.
If you want a literal "%", do not put anything between the two
percent signs, just write "%%".
"errf" formatting codes
require a set of arguments between the
"%" and the formatting code letter. These arguments are placed in
curly braces and separated by semicolons. The first argument is the name of
the data to look for in the format data. For example, this is a valid use of
"errf":
errf "The current time in %{tz}s is %{now;local}t.", {
tz => $ENV{TZ},
now => time,
};
The second argument, if present, may be a compact form for multiple named
arguments. The rest of the arguments will be named values in the form
"name=value". The examples below should help clarify how arguments
are passed. When an argument appears in both a compact and named form, the
named form trumps the compact form.
The specific codes and their arguments are:
s for string
The "s" format code is for any string, and takes no arguments. It just
includes the named item from the input data.
errf "%{name}s", { name => 'John Smith' }; # returns "John Smith"
Remember, "errf" does
not have any of the left- or
right-padding formatting that "sprintf" provides. It is not meant
for building tables, only strings.
i for integer
The "i" format code is used for integers. It takes one optional
argument, "prefix", which defaults to the empty string.
"prefix" may be given as the compact argument, standing alone.
"prefix" is used to prefix non-negative integers. It may only be a
plus sign.
errf "%{x}i", { x => 10 }; # returns "10"
errf "%{x;+}i", { x => 10 }; # returns "+10"
errf "%{x;prefix=+}i", { x => 10 }; # returns "+10"
The rounding behavior for non-integer values
is not currently specified.
f for float (or fractional)
The "f" format code is for numbers with sub-integer precision. It
works just like "i", but adds a "precision" argument which
specifies how many decimal places of precision to display. The compact
argument may be just the prefix or the prefix followed by a period followed by
the precision.
errf "%{x}f", { x => 10.1234 }; # returns "10";
errf "%{x;+}f", { x => 10.1234 }; # returns "+10";
errf "%{x;.2}f", { x => 10.1234 }; # returns "10.12";
errf "%{x;+.2}f", { x => 10.1234 }; # returns "+10.12";
errf "%{x;precision=.2}f", { x => 10.1234 }; # returns "10.12";
errf "%{x;prefix=+;precision=.2}f", { x => 10.1234 }; # returns "+10.12";
t for time
The "t" format code is used to format timestamps provided in epoch
seconds. It can be given two arguments: "type" and "tz".
"type" can be either date, time, or datetime, and indicates what part
of the timestamp should be displayed. The default is datetime. "tz"
requests that the timestamp be displayed in either UTC or the local time zone.
The default is local.
The compact form is just "type" alone.
# Assuming our local time zone is America/New_York...
errf "%{x}t", { x => 1280530906 }; # "2010-07-30 19:01:46"
errf "%{x;type=date}t", { x => 1280530906 }; # "2010-07-30"
errf "%{x;type=time}t", { x => 1280530906 }; # "19:01:46"
errf "%{x;type=datetime}t", { x => 1280530906 }; # "2010-07-30 19:01:46"
errf "%{x;tz=UTC}t", { x => 1280530906 }; # "2010-07-30 23:01:46 UTC"
errf "%{x;tz=UTC;type=date}t", { x => 1280530906 }; # "2010-07-30 UTC"
errf "%{x;tz=UTC;type=time}t", { x => 1280530906 }; # "23:01:46 UTC"
errf "%{x;tz=UTC;type=datetime}t", { x => 1280530906 }; # "2010-07-30 23:01:46 UTC"
n and N for numbered
The "n" and "N" format codes are for picking words based on
number. It takes two of its own arguments, "singular" and
"plural", as well as "prefix" and "precision"
which may be used for formatting the number itself.
If the value being formatted is 1, the singular word is used. Otherwise, the
plural form is used.
errf "%{x;singular=dog;plural=dogs}n", { x => 0 }; # 0 dogs
errf "%{x;singular=dog;plural=dogs}n", { x => 1 }; # 1 dog
errf "%{x;singular=dog;plural=dogs}n", { x => 2 }; # 2 dogs
errf "%{x;singular=dog;plural=dogs}n", { x => 1.4 }; # 1.4 dogs
errf "%{x;singular=dog;plural=dogs;precision=1}n", { x => 1.4 }; # 1.4 dogs
errf "%{x;singular=dog;plural=dogs;precision=0}n", { x => 1.4 }; # 1 dog
If "N" is used instead of "n", the number will not be
included, only the chosen word.
errf "%{x;singular=is;plural=are}N", { x => 0 }; # are
errf "%{x;singular=is;plural=are}N", { x => 1 }; # is
errf "%{x;singular=is;plural=are}N", { x => 2 }; # are
errf "%{x;singular=is;plural=are}N", { x => 1.4 }; # 1.4 are
errf "%{x;singular=is;plural=are;precision=1}N", { x => 1.4 }; # 1.4 are
errf "%{x;singular=is;plural=are;precision=0}N", { x => 1.4 }; # 1 is
The compact form may take any of the following forms:
word - equivalent to singular=word
word+suffix - equivalent to singular=word;plural=wordsuffix
word1/word2 - equivalent to singular=word;plural=word2
If no singular form is given, an exception is thrown. If no plural form is
given, one will be generated according to some basic rules of English noun
orthography.
AUTHOR¶
Ricardo Signes <rjbs@cpan.org>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2013 by Ricardo Signes.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.