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string_list(?String, ?List, +Format)

Conversion between string in different encodings and a character list
String
String or variable.
List
A variable or a list of integers and/or variables.
Format
An atom.

Description

This predicate performs conversion between a string encoded in Format and a list of the corresponding character representations.

If String is instantiated, it is must be a valid string in the encoding format specified by Format. It is then decoded and List is unified with a list of the corresponding character representations.

If List is instantiated, it is must contain character representations that are valid for the encoding format specified by Format. These characters are then encoded into a string which is unified with String.

Currently supported formats are:

bytes or octet
Every byte in the string corresponds to a list integer in the range 0..255.
chars
Every character in the string corresponds to a single-character atom in the list. This format assumes a default character encoding.
codes
Every character in the string corresponds to an integer character code in the list. This format assumes a default character encoding.
utf8
The string is encoded in UTF-8 format and the list can contain integers in the range 0..2^31-1.

Note that string_list/2 can be defined as: 

	string_list(S, L) :- string_list(S, L, bytes).

Modes and Determinism

Exceptions

(4) instantiation fault
Format is not instantiated.
(4) instantiation fault
Neither String nor List are ground.
(5) type error
String is neither a string nor a variable.
(5) type error
List is neither a list nor a variable.
(5) type error
Format is not an atom.
(6) out of range
One (or more) elements of List are not of the type corresponding to Format.
(6) out of range
Format is not a valid format specification.
(6) out of range
One (or more) elements of List are not integers or atoms in the valid range for Format.

Examples

    [eclipse 1]: string_list(S,[65,66,67],bytes).
    S = "ABC"
    yes.

    [eclipse 2]: string_list(S, [65,66,67], utf8).
    S = "ABC"
    yes.

    [eclipse 3]: string_list(S, [65, 0, 700, 2147483647], bytes).
    out of range in string_list(S, [65, 0, 700, 2147483647])

    [eclipse 4]: string_list(S, [65, 0, 700, 2147483647], utf8).
    S = "A\000\312\274\375\277\277\277\277\277"
    yes.

See Also

string_list / 2, write / 2, read_string / 4