Created SET symbols

You can create SET symbols during the generation of a macro. A created SET symbol has the form &(e), where e represents one or more of the following:

Variable symbols, optionally subscripted
Strings of alphanumeric characters
Predefined symbols with absolute values
Other created SET symbols

After substitution and concatenation, e must consist of a string of 1 to 62 alphanumeric characters, the first being alphabetic. This string is then used as the name of a SETx variable. For example:

Name     Operation      Operand

&X(1)    SETC           'A1','A2','A3','A4'
&(&X(3)) SETA           5

&X is a variable whose value is the name of the variable to be updated.

These statements have an effect identical to:

&A3      SETA           5

You can use created SET symbols wherever ordinary SET symbols are permitted, including declarations; they can even be nested in other created SET symbols.

The created SET symbol can be thought of as a form of indirect addressing. With nested created SET symbols, you can use such indirect addressing to any level.

Created SET symbols can also offer an "associative memory" facility. For example, a symbol table of numeric attributes can be referenced by an expression of the form &(&SYM)(&I) to yield the I-th element of the symbol substituted for &SYM. Note that the value of &SYM need not be the name of a valid symbol; thus created SET symbols may have arbitrary names.

Created SET symbols also allow you to achieve some of the effect of multidimensional arrays by creating a separate named item for each element of the array. For example, a three-dimensional array of the form &X(&I,&J,&K) can be addressed as &(X&I.$&J.$&K). Then &X(2,3,4) is represented as a reference to the symbol &X2$3$4.

Note that what is being created here is a SET symbol. Both creation and recognition occur at macro-generation time. In contrast, the names of parameters are recognized and encoded (fixed) at macro-edit time. If a created SET symbol name happens to coincide with a parameter name, the coincidence is ignored and there is no interaction between the two.