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C - metacharacters, Objectives, Description – Rockwell Automation 2755 AdaptaScan Software User Manual

Page 201

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Appendix

C

Metacharacters

This appendix describes metacharacters and how they may be used
in a match table rule, message find string, or replacement message.

The Reader uses special characters 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 embedded within
search or replacement strings. Each metacharacter conveys a
specific instruction to the Reader, and acts upon a clearly defined
range within the string.

There are two distinct sets of metacharacters. One set applies only to
search strings and the other to replacement strings. If the Reader
encounters a search string metacharacter in a replacement string, it
will interpret it as a standard ASCII character. Conversely, if the
decoder detects a replacement string metacharacter in a search string,
it will interpret it as a standard ASCII character. For example, a “*”
in a replacement string is treated as normal text but functions as a
metacharacter in a search string.

Objectives

Description