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scanSet is used to associate characters with a bit that can be used with the PROCEDURE scan.
The BITS value returned by scanSet has a single 1-bit. This bit is associated with the characters of scanChars when used by scan.
There is a limit on the number of bits in use at the same time equal to one less than the number of bits in a BITS value.
Example 47–5. Use of scanSet
BITS letters,digits,lettersAndDigits; scan can use letters for scanning letters, digits for scanning digits, and lettersAndDigits for scanning letters and digits. |
Repeated calls to scanSet for the same scan string return the same scan bit instead of allocating a new scan bit for each call. MAINSAIL keeps track of how often scanSet has been called for a given string. Each time scanRel is called for a given scan bit, its count is decremented, and the scan bit is released only when the decremented count is no longer positive.
$scanSet provides INTEGERs that may be used with scan. Only one INTEGER may be used at a time with scan, but a large number of them are available.
Values returned from scanSet should not be saved in a file or structure image; they are valid only during the current execution.
MAINSAIL Language Manual, Section 47.4