NAME
highlighter - highlight something inside a string
SYNOPSIS
use highlighter;
say highlighter "foo bar", "bar", "<b>", "</b>", :type<words>; # foo <b>bar</b>
say highlighter "foo bar", "bar" but Type<words>, "*"; # foo *bar*
say columns "foo bar", "bar", :type<words>; # (5)
say matches "foo bar", "O", :type<contains>, :ignorecase; # o o
DESCRIPTION
The highlighter distribution exports three subroutines by default that are related to highlighting / indicating subsections of strings depending on the result of some type of search.
It also exports a role Type by default, which allows one to associate the type of search wanted for a given string needle.
The highlighter subroutine can be called to highlight a word, a string or the match of a regular expression inside a string.
The columns subroutine returns the columns (1-based) at which highlighting should occur using the same search semantics as with highlighter.
The matches returns the actual matches inside the string as a Slip, using the same search semantics as with highlighter.
SELECTIVE IMPORTING
use highlighter <columns>; # only export sub columns
By default all three subroutines and the Type role are exported. But you can limit this to the functions you actually need by specifying the name(s) in the use statement.
To prevent name collisions and/or import any subroutine (or role) with a more memorable name, one can use the "original-name:known-as" syntax. A semi-colon in a specified string indicates the name by which the subroutine is known in this distribution, followed by the name with which it will be known in the lexical context in which the use command is executed.
use highlighter <columns:the-columns>; # export "columns" as "the-columns"
say the-columns "foo bar", "bar", :type<words>; # (5)
use highlighter <Type:Needle>; # export "Type" as "Needle"
say columns "foo bar", "bar" but Needle<words>; # (5)
EXPORTED SUBROUTINES
highlighter
The highlighter subroutine for a given string (the haystack), returns a string with highlighting codes for a word, a string or the match of a regular expression (the needle) with a given highlight string. Returns the haystack If the needle could not be found.
use highlighter 'highlighter';
say highlighter "foo bar", "bar", "<b>", "</b>", :type<words>; # foo <b>bar</b>
say highlighter "foo bar", "O", "*", :type<contains>, :ignorecase; # f*o**o* bar
say highlighter "foo bar", "fo", "*", :type<starts-with>; # *fo*o bar
say highlighter "foo bar", "ar", "*", :type<ends-with>; # foo b*ar*
say highlighter "foo", "foo", "*", :type<equal>; # *foo*
say highlighter "foo bar", / b.r /, "*"; # foo *bar*
The following positional parameters can be passed:
This is the string in which things should be highlighted.
This is either a string, or a regular expression indicating what should be highlighted, or a list of strings / regular expressions.
If a list was specified, then the highlighter subroutine will be called for all elements in the list, and the first actually producing a highlighted string, will be returned.
This is the string that should be put before the thing that should be highlighted.
Optional. This is the string that should be put after the thing that should be highlighted. Defaults to the before string>.
The following optional named arguments can also be specified:
Optional named argument. If the needle is a regular expression, it is ignored. Otherwise "contains" is assumed.
It indicates the type of search that should be performed. Possible options are words (look for the needle at word boundaries only), contains (look for the needle at any position), starts-with (only look for the needle at the start of the string), ends-with (only look for the needle at the end of the string) and equal (if needle is the same size as the string and starts at the beginning of the string).
Optional named argument. If the second positional argument is a string, then this indicates whether any searches should be done in a case insensitive manner.
Optional named argument. If the second positional argument is a string, then this indicates whether any searches should be done on the base characters only.
Optional named argument. Indicates that only the strings that were found should be returned (and not have anything inbetween, except for any before and after strings). Defaults to False.
Optional named argument. Indicates the number of characters a string must exceed to have the non-highlighted parts shortened to try to fit the indicated number of characters. Defaults to Any, indicate no summarizing should take place.
columns
The columns subroutine returns the columns (1-based) at which highlighting should occur, given a haystack, needle and optional named arguments.
use highlighter 'columns';
say columns "foo bar", "bar", :type<words>; # (5)
say columns "foo bar", "O", :type<contains>, :ignorecase; # (2,3)
say columns "foo bar", "fo", :type<starts-with>; # (1)
say columns "foo bar", "ar", :type<ends-with>; # (6)
say columns "foo", "foo", :type<equal>; # (1)
say columns "foo bar", / b.r /; # (5)
The following positional parameters can be passed:
This is the string in which should be searched to determine the column positions.
This is either a string, or a regular expression indicating what should be searched for to determine the column positions, or a list of strings and regular exprssions.
If a list was specified, then the columns subroutine will be called for all elements in the list, and the first actually producing a result, will be returned.
The following named arguments can also be specified:
Optional named argument. If the needle is a regular expression, it is ignored. Otherwise "contains" is assumed.
It indicates the type of search that should be performed. Possible options are words (look for the needle at word boundaries only), contains (look for the needle at any position), starts-with (only look for the needle at the start of the string), ends-with (only look for the needle at the end of the string) and equal (if needle is the same size as the string and starts at the beginning of the string).
Optional named argument. If the second positional argument is a string, then this indicates whether any searches should be done in a case insensitive manner.
Optional named argument. If the second positional argument is a string, then this indicates whether any searches should be done on the base characters only.
matches
The matches subroutine returns the actual matches inside the string as a Slip for the given haystack and needle and optional named arguments.
use highlighter 'matches';
say matches "foo bar", "bar", :type<words>; # bar
say matches "foo bar", "O", :type<contains>, :ignorecase; # o o
say matches "foo bar", "fo", :type<starts-with>; # fo
say matches "foo bar", "ar", :type<ends-with>; # ar
say matches "foo", "foo", :type<equal>; # foo
say matches "foo bar", / b.r /; # bar
This is the string from which any matches should be returned.
This is either a string, or a regular expression indicating what should be used to determine what a match is, or a list consisting of strings and regular expressions.
If a list was specified, then the matches subroutine will be called for all elements in the list, and the first actually producing a result, will be returned.
The following named arguments can also be specified:
Optional named argument. If the needle is a regular expression, it is ignored. Otherwise "contains" is assumed.
It indicates the type of search that should be performed. Possible options are words (look for the needle at word boundaries only), contains (look for the needle at any position), starts-with (only look for the needle at the start of the string), ends-with (only look for the needle at the end of the string) and equal (if needle is the same size as the string and starts at the beginning of the string).
Optional named argument. If the second positional argument is a string, then this indicates whether any searches should be done in a case insensitive manner.
Optional named argument. If the second positional argument is a string, then this indicates whether any searches should be done on the base characters only.
NOTES
Callable as a needle
If a simple Callable (rather than a Regex) is passed as a needle, then the haystack will always be returned, as there is no way to determine what will need to be highlighted. Any other arguments, apart from the :summary-if-larger-than named argument, will be ignored.
AUTHOR
Elizabeth Mattijsen liz@raku.rocks
COPYRIGHT AND LICENSE
Copyright 2021, 2022 Elizabeth Mattijsen
Source can be located at: https://github.com/lizmat/highlighter . Comments and Pull Requests are welcome.
If you like this module, or what I’m doing more generally, committing to a small sponsorship would mean a great deal to me!
This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.