String::Errf(3) User Contributed Perl Documentation String::Errf(3)NAMEString::Errf - a simple sprintf-like dialect
VERSION
version 0.006
SYNOPSIS
use String::Errfqw(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.
DESCRIPTIONString::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.
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 "%%".
FORMATTING CODES
"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) 2010 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.
perl v5.14.1 2010-10-29 String::Errf(3)
