PERL is a tool that allows computer to find strings of characters in text very quickly.

Enter a text in the text zone, then a string of characters, then choose a color to color all occurrences of the string of characters in the text.

PERL allows users to enter queries as patterns of characters, i.e. string of characters in which one can specify generic types of characters. These queries are called “PERL-style regular expressions”. For instance, the PERL character “.” stands for “any character”. Therefore, the PERL-style regular expression “.ar.” will color in the text all the occurrences of “bare”, “cart”, “dart”, etc.

A few PERL-style special queries:

a* stands for any number of “a”s (e.g. “aaaa”)

.* stands for any number of characters (e.g. “abcd”)

[A-Z]* represents all word forms in uppercase letters, e.g. “TITLE”

[A-Z][a-z]* represents word forms that start with an uppercase letter ([A-Z]) followed by any number of lowercase letters ([a-z]), e.g. “Title”

(1-[0-9][0-9][0-9]) [0-9][0-9][0-9] [0-9][0-9][0-9][0-9] represents phone numbers such as (1-212) 123 4567.

^a.*y$ recognizes all lines that start with an “a” and end with a “y”. “^” represents the beginning of lines, whereas “$” represents the end of lines.

Note that in NooJ, linguistic units are the word form (in morphology) or the sentence (in syntax). For instance the NooJ query <ADV+MP=”y$”> will recognize all the adverbs (ADV) that end with a “y”.