&MASKCHK

Returns a string that indicates the matching of a value against a nominated wildcard mask.

&MASKCHK mask data [ wildcard | * ]

&MASKCHK is a built-in function and must be used to the right of an assignment statement.

&MASKCHK is used to perform generic pattern matching. The mask is a string of characters containing wildcard characters, by default asterisks (*), which imply that any character is accepted in positions occupied by wildcard characters, when testing the data string.

This provides a rapid way of determining if the target data is within an acceptable range, or matches specific selection criteria.

Testing the mask against data is performed on a character by character basis moving from left to right. After this comparison, one of the following values is returned:

EQ: The data matches the supplied mask and is the same length as the mask.
EQL: The data matches the supplied mask, but is longer than the mask. This implies the supplied mask contains a wildcard character as its last character.
EQS: The data matches the supplied mask, but is shorter than the mask.
NE: The data does not match the supplied mask.

Operands:

mask: A selection mask from 1 to 256 characters in length containing one or more wildcard characters. By default the wildcard character is an asterisk (*), but an alternative character is specified. A wildcard character within mask implies that any value in that data position is accepted. If the last character of mask is a wildcard character, then no further data checking is performed and any trailing characters are accepted.
data: 1 to 256 characters of target data to be scanned to see if it matches the selection criteria established by mask.
wildcard | *: A single character regarded as a wildcard character. By default an asterisk is used. Multiple occurrences of this character, in any position of mask is acceptable.

Examples: &MASKCHK

&A = &MASKCHK IST* &MSGID
&IF &A = EQ &THEN +
   &GOSUB .PROCESSIST

&A = &MASKCHK ABC* ABCD   -* &A will be set to EQ
&A = &MASKCHK A*C* ABCD   -* &A will be set to EQ
&A = &MASKCHK %%C% A*CD % -* &A will be set to EQ
&A = &MASKCHK ABC* ABCDE  -* &A will be set to EQL
&A = &MASKCHK ABC* ABC    - * &A will be set to EQS
&A = &MASKCHK ABC* DEF    -* &A will be set to NE

Note:

When using &MASKCHK, a procedure must allow for when a value of EQ, EQL, or EQS is returned. In such cases the following approach is used:

&A = &MASKCHK P* &TERM &IF &A NE NE &THEN &WRITE Mask matched successfully