<@REGEX>

Syntax

<@REGEX EXPR=expression STR=text TYPE=type>

Description

Provides an interface to POSIX regular expression matching routines from inside Tango. This gives you powerful tools to match text patterns if they are needed.

<@REGEX> accepts as attributes the regular expression (EXPR), the text to match the pattern against (STR), and the type of the regular expression (TYPE), basic or extended. If the attributes contain spaces, they must be quoted--single or double, as appropriate. <@REGEX> returns its results in the form of an array and should be assigned to a variable via <@ASSIGN>.

Upon a successful match, <@REGEX> returns an array with three columns and n+1 rows, where n is the number of parenthesized subexpressions in the pattern. The first column contains the matching text, the second column contains the start index of the matching portion, and the third column gives the length of the matching portion. The start and length are compatible with the <@SUBSTRING> tag.

Rows i from 1 to n give the ith matching parenthesized subexpression, and row n+1 gives the entire matching portion of the text. (If there are no parenthesized subexpressions, the whole match is returned in the first row.)

The table gives a sample array returned from <@REGEX>.

<@REGEX EXPR="([[:alpha:]]+),[[:space:]]+([A-Z]{2})[[:space:]]+([A-Z][0-9][A-Z] [0-9][A-Z][0-9])" STR="in Mississauga, ON L5N 6J5." TYPE=E>.

If attributes are missing, <@REGEX> returns a string with the problem attributes. Upon an error condition, <@REGEX> returns a single character, "C" for a pattern compile failure, and an "M" for a match failure. If any attributes are missing, a textual message is displayed indicating the missing items. You can easily test for success by using <@VARINFO NAME=variable ATTRIBUTE=TYPE>.

Tip: For more information on constructing POSIX regular expressions, ask your local UNIX guru, consult the FreeBSD regex man page, or try doing an internet search for the term "POSIX 1003.2".