MACRO TO INSTANTIATE A VARIABLE USED WITH A FIRST MACRO REQUIRING USE OF A SECOND MACRO SUITABLE FOR SAID VARIABLE

A programmer creates a computer program in assembly language by use of a first macro to identify an operation to be performed on a variable without knowledge of one or more assembly language instructions required to perform the operation. A macro expander (that may be tightly coupled to an assembler) receives the programmer-specified first macro and its argument(s), uses the variable's class type to identify a macro name of a second macro, and invokes this second macro with the argument(s). The macro expander also expands the second macro to generate appropriate assembler instruction(s) to perform the operation. The assembler instructions are automatically changed by the macro expander in an appropriate manner if any of the just-described attributes is changed, so as to still perform the operation indicated by the programmer-specified first macro. Therefore, the programmer may write a program in the assembly language using a high level language syntax.