eval -- r7rs Definition

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Kind

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procedure;

Implemented by

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• eval (from vonuvoli);

Procedure signature

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Procedure variants:

• ((eval-expression eval-environment) -> (any))
  • inputs:
    • a value of type eval-expression;
    • a value of type eval-environment;
  • output: a value of type any;

Exports

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• scheme:eval -- (scheme eval);

Exports recursive

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• scheme -- (scheme);

Description

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(eval expr-or-def environment-specifier)

If expr-or-def is an expression, it is evaluated in the specified environment and its values are returned. If it is a definition, the specified identifier(s) are defined in the specified environment, provided the environment is not immutable. Implementations may extend eval to allow other objects.

(eval '(* 7 3) (environment '(scheme base)))
                                                   ===>  21

(let ((f (eval '(lambda (f x) (f x x))
               (null-environment 5))))
  (f + 10))
                                                   ===>  20
(eval '(define foo 32)
      (environment '(scheme base)))
                                                   ===>  #error

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The text herein was sourced and adapted as described in the "R7RS attribution of various text snippets" appendix.

Referenced-types

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• eval-expression;
• eval-environment;
• any;