Difference Between Macro Substitution and Named Expression

• Microsoft Visual FoxPro for Windows, version 3.0
• Microsoft FoxPro for MS-DOS, versions 2.0, 2.5, and 2.5a
• Microsoft FoxPro for Windows, versions 2.5 and 2.5a

SUMMARY

Macro substitution and name expressions are both methods used to place the value of a variable in a FoxPro command. The fundamental difference between the two is that with name expressions, the value of the variable is substituted before execution. With macro substitution, the value is substituted during execution.

MORE INFORMATION

The FoxPro language compiler parses the program and replaces a name expression with the value during the first pass; from that point on, only the value, not the variable, is used. The FoxPro compiler leaves a macro substitution as a reference to the variable that is not resolved until the program is executed.

If you use a name expression and the variable changes during execution, the new value of the variable is not used. However, if you use a macro substitution, the new value will be substituted.