HLASM Language Reference

Symbolic Parameters
A variable symbol
A combination of variable symbols and other character strings concatenated
together
If the DBCS assembler option is specified, character strings may contain
double-byte data, provided the character strings are enclosed by apostrophes.
The allowable results of generation are spaces (if valid) and a character string that
represents a valid assembler, machine instruction, or macro instruction operand
field.
Variable Symbols: Variable symbols must not be used in the operand field of a
ICTL, or ISEQ instruction. A variable symbol must not be used in the operand field
of a COPY instruction that is inside a macro definition.
Remarks Field
The remarks field of a model statement can contain any combination of characters.
No substitution is done for variable symbols appearing in the remarks field.
Using spaces: One or more spaces must be used in a model statement to
separate the name, operation, operand, and remarks fields from each other.
Spaces cannot be generated between fields in order to create a complete
assembler language statement. The exception to this rule is that a combined
operand-remarks field can be generated with one or more spaces to separate the
two fields. Note, however, that if the generated operand field is part of a macro
instruction, the entire string (including spaces) is passed as an operand.
Symbolic Parameters
Symbolic parameters let you receive values into the body of a macro definition from
the calling macro instruction. You declare these parameters in the macro prototype
statement. They can serve as points of substitution in the body of the macro
definition and are replaced by the values assigned to them by the calling macro
instruction.
By using symbolic parameters with meaningful names, you can indicate the
purpose for which the parameters (or substituted values) are used.
Symbolic parameters must be valid variable symbols. A symbolic parameter
consists of an ampersand followed by an alphabetic character and from 0 to 61
alphanumeric characters.
The following are valid symbolic parameters:
&READER &LOOP2
&A23456 &N
&X4F2 &$4
The following are not valid symbolic parameters:
CARDAREA first character is not an ampersand
&256B first character after ampersand is not alphabetic
&BCD%34 contains a special character other than initial ampersand
&IN AREA contains a special character [space] other than initial ampersand
Chapter 7. How to Specify Macro Definitions 253