HLASM Language Reference

Substring Notation
LCLC &C1,&C2
LCLC &SUBSCRC(2)
. ▲
┌─── ▌1▐ . └─── ▌2▐
▼ .
&SUBSCRC(1) SETC 'ABCDE'
. │
. │
. │
────────────────────────┼──────────────────────────────────────────────
▌3▐─────┐
&SUBSCRC Array:
│
▼
┌─────┬─────┬─────┬────/ /────┬─────┬─────┬─────┬────/ /────┬─────┐
│ │ │ │ │ABCDE│ │ │ │ │
└─────┴─────┴─────┴────/ /────┴─────┴─────┴─────┴────/ /────┴─────┘
▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
1 2 3 4 1 11 12 13 2
Figure 102. Subscripted SETC Symbols
Character (SETC) Expressions
The main purpose of a character expression is to assign a character value to a
SETC symbol. You can then use the SETC symbol to substitute the character
string into a model statement.
You can also use a character expression as a value for comparison in condition
tests and logical expressions. Also, a character expression provides the string from
which characters can be selected by the substring notation.
Substitution of one or more character values into a character expression lets you
use the character expression wherever you need to vary values for substitution or
to control loops.
A character string consists of any combination of characters enclosed in single
quotation marks. Variable symbols are allowed. The assembler substitutes the
representation of their values as character strings into the character expression
| before evaluating the expression. Up to 1024 characters are allowed in a character
expression.
An attribute reference must be the only term in a character expression.
Substring Notation: The substring notation lets you refer to one or more
characters within a character string. You can, therefore, either select characters
from the string and use them for substitution or testing, or scan through a complete
string, inspecting each character. By concatenating substrings with other
substrings or character strings, you can rearrange and build your own strings.
The substring notation can be used only in conditional assembly instructions.
Figure 103 shows how to use the substring notation.
Chapter 9. How to Write Conditional Assembly Instructions 371