In programming languages, a macro is any programming or user interface that allows one to associate a macro name to a set of instructions to be substituted whereever the macro name appears in a program. The macro, when used, expands into something usually larger than itself. 
Often, the macro facility allows arguments to be substitued into the exapanded code.  Sometimes, the facility permits conditional expansion, internalized dynamic generation of unique names, etc.

Tcl has several macro systems.
   * [expand]
   * [Sugar]
   * [Tmac - a Tcl macro processor package]
   * [tpp]


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[Category Glossary]