Macro WITH-UNIQUE-NAMES

Syntax:

with-unique-names ({var | (var prefix)}*) declaration* form* => result*

Arguments and Values:

var---a symbol; not evaluated.

prefix---a string designator; not evaluated. The default is var.

declaration---a declare expression; not evaluated.

form---a form.

results---the values returned by the forms.

Description:

Executes a series of forms with each var bound to a fresh, uninterned symbol. The uninterned symbol is created as if by a call to gensym with the string denoted by prefix---or, if prefix is not supplied, the string denoted by var---as argument.

Examples:

    (with-unique-names (sym1) sym1)  =>  #:SYM13142
    (with-unique-names ((sym1 "SYM1-")) sym1)  => #:SYM1-3143
    (find-symbol "SYM1-3143")  =>  NIL, NIL
    (with-unique-names ((sym #\Q)) sym) => #:Q3144
    (with-unique-names ((sym1 :sym1-)) sym1) => #:SYM1-3145
    (with-unique-names (sym1) (symbol-package sym1))  =>  NIL
    (with-unique-names (sym8) (eq sym8 sym8))  =>  T
    (with-unique-names (sym9) (set sym9 42) (symbol-value sym9))  =>  42

Side Effects:

Might increment *gensym-counter* once for each var.

Affected by:

*gensym-counter*

Exceptional Situations:

None.

See Also:

gensym, let

Notes:

This is an extension of the classic macro with-gensyms. In fact, cl-utilities also exports with-gensyms, and it can be used as usual. The exported with-gensyms is actually just an alias for with-unique-names which gives a warning at compile-time if the extensions of with-unique-names are used.

You are encouraged to use with-unique-names instead of with-gensyms because it is a little more flexible and because it tells what is going on rather than how it works. This is a somewhat controversial point, so go ahead and use whichever you like if you have an opinion on it. But if you're a newbie who honestly doesn't care, please use with-unique-names.