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Bulletin 2755
Single/Dual-Head Enhanced Bar Code Decoders
16
Metacharacters
The decoder provides a complete set of special purpose characters you can
use to perform logical functions on characters, expressions, or even entire
strings. These characters are known as metacharacters. Metacharacters are
string manipulation commands consisting of standard ASCII characters
which you can embed within search or replacement strings. Each
metacharacter conveys a specific instruction to the decoder software, and acts
upon a clearly defined range within the string. Metacharacters can be used
with standard alphanumeric characters to describe and manipulate even the
most complex substitution scenarios with ease.
Table 2
Search Pattern Metacharacters – Position Dependent
Character
Note: The following two metacharacters are position-dependent. They must
appear in the location specified to be matched.
^
If the circumflex ( ^ ) is used as the first character in the search pattern, it indicates
that the characters, other metacharacters, expressions, or strings must occur at the
beginning of the string to be matched. Note that the circumflex has a special
meaning if used within square brackets, as explained elsewhere in this chapter.
When the dollar sign is used as the last character in the search pattern, it indicates
$
that the characters, other metacharacters, expressions or strings must occur at the
end of the string to be matched.
.
The period represents any single character, and is used as a single-character
"wildcard".
Note: These metacharacters refer to the character, metacharacter, string, or
expression that immediately precedes them.
?
The question mark instructs the rule to match either no occurrence or one
occurrence of what precedes it. This metacharacter is used in a search string
where the character may not appear at all, or may appear once.
+
The plus sign instructs the rule to match one or more occurrences of what
precedes it. This metacharacter is used in a search string where the character will
be present, but you are unsure how many times it appears.
*
The asterisk instructs the rule to match none or more occurrences of what
precedes it. This metacharacter is used in a search string in cases where the
character may not appear, or may appear one or more times.
Description and Use
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