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(elisp)Problems with Macros

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Common Problems Using Macros
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   The basic facts of macro expansion have counterintuitive
consequences.  This section describes some important consequences that
can lead to trouble, and rules to follow to avoid trouble.

Wrong Time

Do the work in the expansion, not in the macro.

Argument Evaluation

The expansion should evaluate each macro arg once.

Surprising Local Vars

Local variable bindings in the expansion

require special care.

Eval During Expansion

Don't evaluate them; put them in the expansion.

Repeated Expansion

Avoid depending on how many times expansion is done.