HP OpenVMS Systems Documentation

HP COBOL
User Manual

When several tally arguments contain one or more identical characters active at the same time, they may interfere with each other, so that when one of the arguments finds a match, the scanner steps past any other matching characters, preventing those characters from being considered for a match.

The following two identical tally arguments do not interfere with each other because they are not active at the same time. The first A in FIELD1 causes the first argument to become inactive and the second argument to become active:

MOVE 0 TO T1 T2.
INSPECT FIELD1 TALLYING
        T1 FOR ALL "," BEFORE "A"
        T2 FOR ALL "," AFTER "A".

However, the next identical tally arguments interfere with each other since both are active at the same time:

INSPECT FIELD1 TALLYING
        T1 FOR ALL ","
        T2 FOR ALL "," AFTER "A".

For any given position of the scanner, the arguments are applied to FIELD1 in the order in which they appear in the statement. When one of them finds a match, the scanner moves to the next position and ignores the remaining arguments in the argument list. Each comma in FIELD1 causes T1 to be incremented by 1 and the second argument to be ignored. Thus, T1 always contains an accurate count of all the commas in FIELD1, and T2 is always unchanged.

The following INSPECT statement arguments only partially interfere with each other:

INSPECT FIELD1 TALLYING
        T2 FOR ALL "," AFTER "A"
        T1 FOR ALL ",".

The first argument does not become active until the scanner encounters an A. The second argument tallies all commas that precede the A. After the A, the first argument counts all commas and causes the second argument to be ignored. Thus, T1 contains the number of commas that precede the first A, and T2 contains the number of commas that follow the first A. This statement works well as written, but it could be difficult to debug.

The following three examples show that one INSPECT statement cannot count any character more than once. Thus, when you use the same character in more than one argument of an argument list, consider the possibility of interference and choose the order of the arguments carefully. The solution may require two or more INSPECT statements. Consider the following problem:

INSPECT FIELD1 TALLYING
        T1 FOR ALL "AB"
        T2 FOR ALL "BC".

If FIELD1 contains ABCABC after the scan, T1 is incremented by 2, and T2 is unaltered. The successful matching of the argument includes each B in the item. Each match resets the scanner to the character position to the right of the B, so that the second argument is never successfully matched. The results remain the same even if the order of the arguments is reversed. Only separate INSPECT statements can develop the desired counts.

Sometimes you can use the interference characteristics of the INSPECT statement to your advantage. Consider the following sample argument list:

MOVE 0 TO T4 T3 T2 T1.
INSPECT FIELD1 TALLYING
        T4 FOR ALL "****"
        T3 FOR ALL "***"
        T2 FOR ALL "**"
        T1 FOR ALL "*".

The argument list counts all of the asterisks in FIELD1 in four different tally counters. T4 counts the number of times that four asterisks occur together; T3 counts the number of times three asterisks appear together; T2 counts double asterisks; and T1 counts singles.

If FIELD1 contains a string of more than four consecutive asterisks, the argument list breaks the string into groups of four and counts them in T4. It then counts the less-than-four remainder in T3, T2, or T1.

Reversing the order of the arguments in this list causes T1 to count all of the asterisks, and T2, T3, and T4 to remain unchanged.

When the LEADING condition is used with an argument in the argument list, that argument becomes inactive as soon as it fails to be matched in the item being inspected. Therefore, when two arguments in an argument list contain one or more identical characters and one of the arguments has a LEADING condition, the argument with the LEADING condition should appear first. Consider the following sample statement:

MOVE 0 TO T1 T2.
INSPECT FIELD1 TALLYING
        T1 FOR LEADING "*"
        T2 FOR ALL "*".

T1 counts only leading asterisks in FIELD1; the occurrence of any other character causes the first tally argument to become inactive. T2 keeps a count of any remaining asterisks in FIELD1.

Reversing the order of the arguments in the following statement results in an argument list that can never increment T1:

INSPECT FIELD1 TALLYING
        T2 FOR ALL "*"
        T1 FOR LEADING "*".

If the first character in FIELD1 is not an asterisk, neither argument can match it, and the second argument becomes inactive. If the first character in FIELD1 is an asterisk, the first argument matches it and causes the second argument to be ignored. The first character in FIELD1 that is not an asterisk fails to match the first argument, and the second argument becomes inactive because it has not found a match in any of the preceding characters.

An argument with both a LEADING condition and a BEFORE phrase can sometimes successfully delimit the item being inspected, as in the following example:

MOVE 0 TO T1 T2.
INSPECT FIELD1 TALLYING
        T1 FOR LEADING SPACES
        T2 FOR ALL "   " BEFORE "."
        T2 FOR ALL "  " BEFORE "."
        T2 FOR ALL " " BEFORE ".".
IF T2 > 0 ADD 1 TO T2.

These statements count the number of words in the English statement in FIELD1, assuming that no more than three spaces separate the words in the sentence, that the sentence ends with a period, and that the period immediately follows the last word. When FIELD1 has been scanned, T2 contains the number of spaces between the words. Because a count of the spaces renders a number that is one less than the number of words, the conditional statement adds 1 to the count.

The first argument removes any leading spaces, counting them in a different tally counter. This shortens FIELD1 by preventing the application of the second to the fourth arguments until the scanner finds a nonspace character. The BEFORE phrase on each of the other arguments causes them to become inactive when the scanner reaches the period at the end of the sentence. Thus, the BEFORE phrases shorten FIELD1 by making the second to the fourth arguments inactive before the scanner reaches the rightmost position of FIELD1. If the sentence in FIELD1 is indented with tab characters instead of spaces, a second LEADING argument can count the tab characters. For example:

INSPECT FIELD1 TALLYING
        T1 FOR LEADING SPACES
        T1 FOR LEADING TAB
        T2 FOR ALL "    "
        .
        .
        .

When an argument list contains a CHARACTERS argument, it should be the last argument in the list. Because the CHARACTERS argument always matches the item, it prevents the application of any arguments that follow in the list. However, as the last argument in an argument list, it can count the remaining characters in the item being inspected. Consider the following example.

MOVE 0 TO T1 T2 T3 T4 T5.
INSPECT FIELD1 TALLYING
        T1 FOR LEADING SPACES
        T2 FOR ALL "." BEFORE ","
        T3 FOR ALL "+" BEFORE ","
        T4 FOR ALL "-" BEFORE ","
        T5 FOR CHARACTERS BEFORE ",".

If FIELD1 is known to contain a number in the form frequently used to input data, it can contain a plus or minus sign, and a decimal point; furthermore, the number can be preceded by spaces and terminated by a comma. When this statement is compiled and executed, it delivers the following results:

• T1 contains the number of leading spaces.
• T2 contains the number of periods.
• T3 contains the number of plus signs.
• T4 contains the number of minus signs.
• T5 contains the number of remaining characters (assumed to be numeric).

The sum of T1 to T5, plus 1, gives the character position occupied by the terminating comma.