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get_chtab(+Char, ?Class)

Succeeds if the lexical class of character Char is Class.

+Char: Integer in the range 0 to 255.
?Class: Atom giving class name or variable.

Description

Retrieves or checks the lexical class of a given character.

Class is unified with the current lexical character class of Char.

Char must be an integer in the range 0 to 255 (an escaped ASCII code is also acceptable, eg 0'a = 98).

The following table lists the character classes and the corresponding default characters:

 Class          Default member characters
---------------------------------------------------------
 upper_case     all upper case letters
 underline      _
 lower_case     all lower case letters
 digit          digits
 blank_space    space, tab, carriage return (CR) etc
 end_of_line    newline (NL)
 atom_quote     '
 string_quote   "
 list_quote
 radix
 ascii
 solo           ( ) ] }
 special        ! , ; [ { |
 line_comment   %
 escape         \
 first_comment  /
 second_comment *
 symbol         # + - . : < = > ? @ ^ ` ~ & $
 unused         ASCII codes 8, 17, 21, 24

Fail Conditions

Fails if class of Char does not unify with Class.

Resatisfiable

Exceptions

(4) instantiation fault: Char in not instantiated.
(5) type error: Char is not an ASCII code.
(6) out of range: Char is not in the range 0 to 255.

Examples