number->string -- r7rs Definition

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Kind

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converter;

Implemented by

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• number->string (from vonuvoli);

Procedure signature

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Procedure variants:

• ((number) -> (string-not-empty))
  • input: a value of type number;
  • output: a value of type string-not-empty;
• ((number number-radix) -> (string-not-empty))
  • inputs:
    • a value of type number;
    • a value of type number-radix;
  • output: a value of type string-not-empty;

Exports

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• scheme:base -- (scheme base);

Exports recursive

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• scheme -- (scheme);

Description

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(number->string z)
(number->string z radix)

Domain: It is an error if radix is not one of 2, 8, 10, or 16.

The procedure number->string takes a number and a radix and returns as a string an external representation of the given number in the given radix such that

(let ((number number)
      (radix radix))
  (eqv? number
        (string->number (number->string number
                                        radix)
                        radix)))

is true. It is an error if no possible result makes this expression true. If omitted, radix defaults to 10.

If z is inexact, the radix is 10, and the above expression can be satisfied by a result that contains a decimal point, then the result contains a decimal point and is expressed using the minimum number of digits (exclusive of exponent and trailing zeroes) needed to make the above expression true; otherwise the format of the result is unspecified.

The result returned by number->string never contains an explicit radix prefix.

Note: The error case can occur only when z is not a complex number or is a complex number with a non-rational real or imaginary part.

Rationale: If z is an inexact number and the radix is 10, then the above expression is normally satisfied by a result containing a decimal point. The unspecified case allows for infinities, NaNs, and unusual representations.

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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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• number;
• string-not-empty;
• number-radix;