Книга: Practical Common Lisp

Local Variables

Local Variables

While the main variables needed within a loop are usually declared implicitly in for clauses, sometimes you'll need auxiliary variables, which you can declare with with clauses.

with var [ = value-form ]

The name var becomes the name of a local variable that will cease to exist when the loop finishes. If the with clause contains an = value-form part, the variable will be initialized, before the first iteration of the loop, to the value of value-form.

Multiple with clauses can appear in a loop; each clause is evaluated independently in the order it appears and the value is assigned before proceeding to the next clause, allowing later variables to depend on the value of already declared variables. Mutually independent variables can be declared in one with clause with an and between each declaration.

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