MATCH

The MATCH instruction compares two character strings or two RECORDS. The instruction uses the following format:

Where:

label

Optional. A Program Execution Label.

source

Required. A previously defined Character String Variable, National Character String Variable, Literal, National Character String Literal, or RECORD that is compared to the {dest} operand.

sep

Required. A comma or one of the following prepositions: BY, TO, OF, FROM, USING, WITH, IN, or INTO.

dest

Required. A previously defined Character String Variable, National Character String Variable, Literal, National Character String Literal, or RECORD that is compared to the {source} operand.

wildcard

Required. A previously defined Character String Variable, National Character String Variable, or constant character indicating source variable wildcard characters.

Flags Affected: EOS, LESS, ZERO

Note the following:

1. Only the Logical String contents of the {source} and {dest} strings are compared.

2. None of the operands, nor their Form Pointers or Length Pointers change.

3. If either operand is a Null String, the LESS and EQUAL Condition Flags are not set (both FALSE) and the EOS Condition Flag is set.

4. The operand length is defined as:
   
   LENGTH = Length Pointer - Form Pointer + 1
    

5. If all characters matched are equal, the EQUAL (or ZERO) Condition Flag is set. The instruction then makes the following calculation:
   
   X = DESTINATION LOGICAL LENGTH - SOURCE LOGICAL LENGTH
   
   If X is negative, the LESS Condition Flag is set.
    

6. If all characters compared are not equal, the instruction makes the following calculation based on the hexadecimal value of the first non-matching character:
   
   X = DESTINATION HEX VALUE - SOURCE HEX VALUE
   
   If X is negative, the LESS Condition Flag is set.
    

7. The optional third parameter ({wildcard}) specifies a character that is treated as a don't care or wildcard character. If the specified character exists in the {source} operand, it matches any character in the destination operand that occupies the same relative position. If {wildcard} is a character string variable, the Form Pointed character is used.

8. If the operands are RECORDs, the MATCH operation is an absolute comparison of each byte in {source} to the corresponding byte in {dest}. The comparison is not being performed on a per member basis and therefore the {wildcard} parameter is not allowed. Specification of the {wildcard} parameter will produce a warning message by the compiler. The MATCH instruction does not support record pointers.

Example 1:

The EQUAL (or ZERO) Condition Flag is set.

Example 2:

The EQUAL (or ZERO) Condition Flag is set. The LESS Condition Flag is also set because the destination field is shorter than the source field.

Example 3:

The LESS Condition Flag is set.

Example 4:

The LESS Condition Flag is set. The hexadecimal value of numeric characters is less than that of alphabetic characters.

Example 5:

The EQUAL (or ZERO) Condition Flag is set. The source operand was shorter than the destination operand. Therefore, the LESS Condition Flag is not set (FALSE).

Example 6:

No Condition Flags are set (all FALSE). The first non-matching source character (C) is less than the first non-matching destination character (X).

Example 7:

The EQUAL (or ZERO) Condition Flag is set.

Example 8:

The EQUAL (or ZERO) Condition Flag is set.

Example 9:

The EQUAL (or ZERO) Condition Flag is cleared. The Logical Length of the second field is shorter in the second record.

See Also: MATCHLIST, CMATCH, Character String Instructions