Number attribute (N')

The number attribute applies to the operands of macro instructions and subscripted SET symbols.

When applied to a macro operand, the number attribute is a numeric value equal to the number of sublist entries.

When applied to a subscripted SET symbol, the number attribute is equal to the highest element to which a value has been assigned in a SETx instruction. Consider the example in Figure 1.

Figure 1. Number attribute reference

                                      1            macro
                                      2            MAC1 &op1
                                      3            lcla &SETSUB(100)
                                      4 &SETSUB(5) seta 20,,,70
                                      5 &B         seta N'&SETSUB
                                      6 &C         seta N'&op1
                                      7            DC C'Highest referenced element of SETSUB = &B'
                                      8            DC C'Number of sublist entries in OP1 = &C'
                                      9            mend
000000                00000 0004C    10 a          csect
                                     11            MAC1 (1,(3),(4))
000000 C889878885A2A340              12+           DC C'Highest referenced element of SETSUB = 8'
000028 D5A4948285994096              13+           DC C'Number of sublist entries in OP1 = 3'
                                     14            end

N'&op1 is equal to 3 because there are three subscripts in the macro operand in statement 11: 1, (3), and (4).

N'&SETSUB is equal to 8 because &SETSUB(8), assigned the value 70 in statement 4, is the highest referenced element of the &SETSUB array entries.

Notes:

The number attribute reference can be used only in arithmetic expressions.
N'&SYSLIST refers to the number of positional operands in a macro instruction, and N'&SYSLIST(n) refers to the number of sublist entries in the n-th operand.
For positional macro parameters, either explicitly named or implicitly named as &SYSLIST(n):
1. If the first character of an operand is a left parenthesis, count the number of unquoted and unnested commas between it and the next matching right parenthesis. That number plus one is the number attribute of the operand.
2. If there is no initial left parenthesis, the number attribute is one.
For all other system variable symbols, the number attribute value is always one. This is also true for &SYSMAC. The range of the subscript for &SYSMAC is 0 - &SYSNEST.
N' is always zero for unsubscripted set symbols. The number attribute (N'), when used with a macro instruction operand, examines its list structure, not the number of characters in the operand. (The number of characters is determined by the count (K') attribute.)