syntax-error -- r7rs Definition

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Kind

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syntax;

Implemented by

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• syntax-error (from vonuvoli);

Syntax signature

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Syntax keywords:

• message: value of type string;
• argument: value of type any;

Syntax variants:

• (_ message)
• (_ message argument |...|)

Exports

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• scheme:base -- (scheme base);

Exports recursive

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• scheme -- (scheme);

Description

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(syntax-error <message> <args> ...)

syntax-error behaves similarly to error except that implementations with an expansion pass separate from evaluation should signal an error as soon as syntax-error is expanded. This can be used as a syntax-rules <template> for a <pattern> that is an invalid use of the macro, which can provide more descriptive error messages. <message> is a string literal, and <args> arbitrary expressions providing additional information. Applications cannot count on being able to catch syntax errors with exception handlers or guards.

(define-syntax simple-let
  (syntax-rules ()
    ((_ (head ... ((x . y) val) . tail)
        body1 body2 ...)
     (syntax-error
      "expected an identifier but got"
      (x . y)))
    ((_ ((name val) ...) body1 body2 ...)
     ((lambda (name ...) body1 body2 ...)
       val ...))))

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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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• string;
• any;