11.3.142 number_chars/2   ISO

Synopsis

number_chars(+Number, -Chars)

number_chars(-Number, +Chars)

Chars is the chars comprising the printed representation of Number.

Arguments

Number

number

Chars

chars

Description

Initially, either Number must be instantiated to a number, or Chars must be instantiated to a proper chars.

If Chars is instantiated to a chars that corresponds to the correct syntax of a number, then Number will be unified with that number.

Else, Number should be instantiated to a number, and Chars will be unified with the chars that make up its printed representation.

Exceptions

instantiation_error

Number is uninstantiated and Chars is not instantiated enough

type_error

Number is not a number or Chars cannot be unified with a chars

representation_error

Chars is a list corresponding to a number that can’t be represented

syntax_error

Chars does not correspond to a syntactically valid number

The check of Chars when Number is instantiated was added in release 4.3 for alignment with the ISO Prolog standard. Previous releases simply failed in this case instead of reporting an error for malformed Chars.

See Also

number_codes/2.