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(librep.info)Special Forms

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Special Forms
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   Special forms are built-in subroutines which the evaluator knows must
be handled specially. The main difference between a special form and a
function is that the arguments applied to a special form are _not_
automatically evaluated--if necessary the special form will evaluate
arguments itself. This will be noted in the documentation of the
special form.

   Special forms are generally used to provide control structures, for
example, the primitive conditional constructs are special forms (if all
of their arguments, including the forms to be conditionally evaluated,
were evaluated automatically this would defeat the object of being
conditional!).

   The special forms supported by `librep' are: `cond', `defvar',
`progn', `quote', `setq'.

 - Function: special-form-p arg
     Returns true if ARG is a special form.

          (special-form-p quote)
              => t