Symbol Tables (from Fraktal SAS Programming)

Control information tokens, referred to as parameters are called macro variables ("variables") when writing MACROs. Macro variables are stored in tables, which have been given the name symbol tables ("tables").

On starting a SAS process a global symbol table is initiated and populated with control information used by the session and non-MACRO programs.

On invocation of a MACRO, a local symbol table is initiated and kept alive during run-time of the MACRO. Local symbol tables disappear on termination of "their" MACRO.

Symbol tables are two-column character type matrices with one single property scope being either global or local. MACRO variable names are stored in the 1st column, MACRO variable values are stored in the 2nd column.

MACRO symbol tables are stored in memory.

MACRO functions are processed in memory.