1String::Errf(3)       User Contributed Perl Documentation      String::Errf(3)
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NAME

6       String::Errf - a simple sprintf-like dialect
7

VERSION

9       version 0.008
10

SYNOPSIS

12         use String::Errf qw(errf);
13
14         print errf "This process was started at %{start}t with %{args;argument}n.\n",
15           { start => $^T, args => 0 + @ARGV };
16
17       ...might print something like:
18
19         This process was started at 2010-10-17 14:05:29 with 0 arguments.
20

DESCRIPTION

22       String::Errf provides "errf", a simple string formatter that works
23       something like "sprintf".  It is implemented using String::Formatter
24       and Sub::Exporter.  Their documentation may be useful in understanding
25       or extending String::Errf.  The "errf" subroutine is only available
26       when imported.  Calling String::Errf::errf will not do what you want.
27

DIFFERENCES FROM SPRINTF

29       The data passed to "errf" should be organized in a single hashref, not
30       a list.
31
32       Formatting codes require named parameters, and the available codes are
33       different.  See "FORMATTING CODES" below.
34
35       As with most String::Formatter formatters, "%" is not a format code.
36       If you want a literal "%", do not put anything between the two percent
37       signs, just write "%%".
38
39   UNDEF HANDLING
40       By default, formatting codes tend to treat "undef" like Perl does:
41       coercing it to an empty string or zero.  This was a bad initial
42       decision and will probably change.  A "on_undef" handler can be
43       provided when importing "errf" to setup a callback for how undefs
44       should be handled.  These two possibilities seem useful:
45
46         # Very lax; undefs always turn into the same string:
47         use String::Errf errf => { on_undef => sub { '(undef)' } };
48
49         # Strict; undefs are never valid:
50         use String::Errf errf => { on_undef => sub {
51           Carp::croak("undef passed to $_[1]{literal}") } };
52         } };
53
54   FORMATTING CODES
55       "errf" formatting codes require a set of arguments between the "%" and
56       the formatting code letter.  These arguments are placed in curly braces
57       and separated by semicolons.  The first argument is the name of the
58       data to look for in the format data.  For example, this is a valid use
59       of "errf":
60
61         errf "The current time in %{tz}s is %{now;local}t.", {
62           tz  => $ENV{TZ},
63           now => time,
64         };
65
66       The second argument, if present, may be a compact form for multiple
67       named arguments.  The rest of the arguments will be named values in the
68       form "name=value".  The examples below should help clarify how
69       arguments are passed.  When an argument appears in both a compact and
70       named form, the named form trumps the compact form.
71
72       The specific codes and their arguments are:
73
74       s for string
75
76       The "s" format code is for any string, and takes no arguments.  It just
77       includes the named item from the input data.
78
79         errf "%{name}s", { name => 'John Smith' }; # returns "John Smith"
80
81       Remember, "errf" does not have any of the left- or right-padding
82       formatting that "sprintf" provides.  It is not meant for building
83       tables, only strings.
84
85       i for integer
86
87       The "i" format code is used for integers.  It takes one optional
88       argument, "prefix", which defaults to the empty string.  "prefix" may
89       be given as the compact argument, standing alone.  "prefix" is used to
90       prefix non-negative integers.  It may only be a plus sign.
91
92         errf "%{x}i",    { x => 10 }; # returns "10"
93         errf "%{x;+}i",  { x => 10 }; # returns "+10"
94
95         errf "%{x;prefix=+}i",  { x => 10 }; # returns "+10"
96
97       The rounding behavior for non-integer values is not currently
98       specified.
99
100       f for float (or fractional)
101
102       The "f" format code is for numbers with sub-integer precision.  It
103       works just like "i", but adds a "precision" argument which specifies
104       how many decimal places of precision to display.  The compact argument
105       may be just the prefix or the prefix followed by a period followed by
106       the precision.
107
108         errf "%{x}f",     { x => 10.1234 }; # returns "10";
109         errf "%{x;+}f",   { x => 10.1234 }; # returns "+10";
110
111         errf "%{x;.2}f",  { x => 10.1234 }; # returns  "10.12";
112         errf "%{x;+.2}f", { x => 10.1234 }; # returns "+10.12";
113
114         errf "%{x;precision=.2}f",          { x => 10.1234 }; # returns  "10.12";
115         errf "%{x;prefix=+;precision=.2}f", { x => 10.1234 }; # returns "+10.12";
116
117       t for time
118
119       The "t" format code is used to format timestamps provided in epoch
120       seconds.  It can be given two arguments: "type" and "tz".
121
122       "type" can be either date, time, or datetime, and indicates what part
123       of the timestamp should be displayed.  The default is datetime.  "tz"
124       requests that the timestamp be displayed in either UTC or the local
125       time zone.  The default is local.
126
127       The compact form is just "type" alone.
128
129         # Assuming our local time zone is America/New_York...
130
131         errf "%{x}t",               { x => 1280530906 }; # "2010-07-30 19:01:46"
132         errf "%{x;type=date}t",     { x => 1280530906 }; # "2010-07-30"
133         errf "%{x;type=time}t",     { x => 1280530906 }; # "19:01:46"
134         errf "%{x;type=datetime}t", { x => 1280530906 }; # "2010-07-30 19:01:46"
135
136         errf "%{x;tz=UTC}t",               { x => 1280530906 }; # "2010-07-30 23:01:46 UTC"
137         errf "%{x;tz=UTC;type=date}t",     { x => 1280530906 }; # "2010-07-30 UTC"
138         errf "%{x;tz=UTC;type=time}t",     { x => 1280530906 }; # "23:01:46 UTC"
139         errf "%{x;tz=UTC;type=datetime}t", { x => 1280530906 }; # "2010-07-30 23:01:46 UTC"
140
141       n and N for numbered
142
143       The "n" and "N" format codes are for picking words based on number.  It
144       takes two of its own arguments, "singular" and "plural", as well as
145       "prefix" and "precision" which may be used for formatting the number
146       itself.
147
148       If the value being formatted is 1, the singular word is used.
149       Otherwise, the plural form is used.
150
151         errf "%{x;singular=dog;plural=dogs}n", { x => 0 }; # 0 dogs
152         errf "%{x;singular=dog;plural=dogs}n", { x => 1 }; # 1 dog
153         errf "%{x;singular=dog;plural=dogs}n", { x => 2 }; # 2 dogs
154
155         errf "%{x;singular=dog;plural=dogs}n", { x => 1.4 }; # 1.4 dogs
156         errf "%{x;singular=dog;plural=dogs;precision=1}n", { x => 1.4 }; # 1.4 dogs
157         errf "%{x;singular=dog;plural=dogs;precision=0}n", { x => 1.4 }; # 1 dog
158
159       If "N" is used instead of "n", the number will not be included, only
160       the chosen word.
161
162         errf "%{x;singular=is;plural=are}N", { x => 0 }; # are
163         errf "%{x;singular=is;plural=are}N", { x => 1 }; # is
164         errf "%{x;singular=is;plural=are}N", { x => 2 }; # are
165
166         errf "%{x;singular=is;plural=are}N", { x => 1.4 }; # 1.4 are
167         errf "%{x;singular=is;plural=are;precision=1}N", { x => 1.4 }; # 1.4 are
168         errf "%{x;singular=is;plural=are;precision=0}N", { x => 1.4 }; # 1 is
169
170       The compact form may take any of the following forms:
171
172         word          - equivalent to singular=word
173
174         word+suffix   - equivalent to singular=word;plural=wordsuffix
175
176         word1/word2   - equivalent to singular=word;plural=word2
177
178       If no singular form is given, an exception is thrown.  If no plural
179       form is given, one will be generated according to some basic rules of
180       English noun orthography.
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183

AUTHOR

185       Ricardo Signes <rjbs@cpan.org>
186

CONTRIBUTORS

188       •   Karen Etheridge <ether@cpan.org>
189
190       •   Pedro Melo <melo@simplicidade.org>
191
193       This software is copyright (c) 2016 by Ricardo Signes.
194
195       This is free software; you can redistribute it and/or modify it under
196       the same terms as the Perl 5 programming language system itself.
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200perl v5.34.0                      2022-01-21                   String::Errf(3)
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