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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 codes.

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 codes.

If List is instantiated, it is must contain character codes 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
every byte in the string corresponds to a list integer in the range 0..255.
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 in 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 in not an atom.
(6) out of range
Format in not a valid format specification.
(6) out of range
One (or more) elements of List are not integers in a 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