107 lines
3.6 KiB
Prolog
107 lines
3.6 KiB
Prolog
/*************************************************************************
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* *
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* YAP Prolog *
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* *
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* Yap Prolog was developed at NCCUP - Universidade do Porto *
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* *
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* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
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* *
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**************************************************************************
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* *
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* File: chtypes.yap *
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* Last rev: 8/2/88 *
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* mods: *
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* comments: implementation of SWI's code_type/2 *
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* *
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*************************************************************************/
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:- system_module( '$_chtypes', [], []).
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/*
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In addition, there is the library library(ctype) providing compatibility to some other Prolog systems. The predicates of this library are defined in terms of code_type/2.
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char_type(?Char, ?Type)
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Tests or generates alternative Types or Chars. The character-types are inspired by the standard C <ctype.h> primitives.
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alnum
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Char is a letter (upper- or lowercase) or digit.
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alpha
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Char is a letter (upper- or lowercase).
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csym
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Char is a letter (upper- or lowercase), digit or the underscore (_). These are valid C- and Prolog symbol characters.
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csymf
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Char is a letter (upper- or lowercase) or the underscore (_). These are valid first characters for C- and Prolog symbols
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ascii
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Char is a 7-bits ASCII character (0..127).
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white
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Char is a space or tab. E.i. white space inside a line.
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cntrl
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Char is an ASCII control-character (0..31).
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digit
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Char is a digit.
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digit(Weigth)
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Char is a digit with value Weigth. I.e. char_type(X, digit(6) yields X = '6'. Useful for parsing numbers.
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xdigit(Weigth)
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Char is a haxe-decimal digit with value Weigth. I.e. char_type(a, xdigit(X) yields X = '10'. Useful for parsing numbers.
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graph
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Char produces a visible mark on a page when printed. Note that the space is not included!
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lower
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Char is a lower-case letter.
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lower(Upper)
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Char is a lower-case version of Upper. Only true if Char is lowercase and Upper uppercase.
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to_lower(Upper)
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Char is a lower-case version of Upper. For non-letters, or letter without case, Char and Lower are the same. See also upcase_atom/2 and downcase_atom/2.
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upper
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Char is an upper-case letter.
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upper(Lower)
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Char is an upper-case version of Lower. Only true if Char is uppercase and Lower lowercase.
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to_upper(Lower)
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Char is an upper-case version of Lower. For non-letters, or letter without case, Char and Lower are the same. See also upcase_atom/2 and downcase_atom/2.
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punct
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Char is a punctuation character. This is a graph character that is not a letter or digit.
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space
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Char is some form of layout character (tab, vertical-tab, newline, etc.).
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end_of_file
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Char is -1.
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end_of_line
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Char ends a line (ASCII: 10..13).
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newline
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Char is a the newline character (10).
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period
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Char counts as the end of a sentence (.,!,?).
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quote
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Char is a quote-character (", ', `).
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paren(Close)
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Char is an open-parenthesis and Close is the corresponding close-parenthesis.
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code_type(?Code, ?Type)
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As char_type/2, but uses character-codes rather than one-character atoms. Please note that both predicates are as flexible as possible. They handle either representation if the argument is instantiated and only will instantiate with an integer code or one-character atom depending of the version used. See also the prolog-flag double_quotes, atom_chars/2 and atom_codes/2.
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*/
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