HLASM Language Reference

Macro Instruction Format
┌─ ▌4▐ Null character string
│ is default value
MACRO
▼
MACCORR &KEY1=DEFAULT,&KEY2=,&KEY3=123
.
.
DC C'&KEY1&KEY2&KEY3'
.
.
MEND
───────────────────────────────────────────────────────────────
OPEN START
.
. ▌1▐ ▌1▐ ▌1▐
MACCOOR KEY1=OVERRIDE,KEY2=,KEY3=456
. │ │ │
. ┌────┘ ┌──────────┘ │
. ▼ ▼ │
+ DC C'OVERRIDE456' │
. ▲ │
. └────────────────┘
.
MACCOOR ▌2▐
. ┌──── KEY2 has null character
. │ string as default
. ▼
+ DC C'DEFAULT123'
.
.
. ▌3▐
MACCOOR KEY4=SYMBOL,KEY2=
ASMA17W WARNING Undefined keyword parameter . . .
.
.
.
+ DC C'DEFAULT123'
.
.
.
MACCOOR KEY1=,KEY3=456
. ┌──────────────────── KEY1 parameter has null
. │ character string value
. ▼ KEY2 has null character
+ DC C'456' string as default
END
Figure 78. Relationship between Keyword Operands and Keyword Parameters and Their
Assigned Values
Combining Positional and Keyword Operands
You can use positional and keyword operands in the same macro instruction. Use
a positional operand for a value that you change often, and a keyword operand for
a value that you change infrequently.
Positional and keyword parameters can be mixed freely in the macro prototype
statement (see ▌1▐ in Figure 79). The same applies to the positional and keyword
operands of the macro instruction (see ▌2▐ in Figure 79). Note, however, that the
order in which the positional parameters appear (see ▌3▐ in Figure 79) determines
Chapter 8. How to Write Macro Instructions 303