This library wraps the utf8proc library, giving Prolog code access to Unicode character properties, string normalization, case folding, and grapheme-cluster iteration.
Three levels of API are provided:
Grapheme clusters (user-perceived characters) can be iterated with atom_graphemes/2 and string_graphemes/2.
Lump handling:
U+0020 <-- all space characters (general category Zs)
U+0027 ' <-- left/right single quotation mark U+2018..2019,
modifier letter apostrophe U+02BC,
modifier letter vertical line U+02C8
U+002D - <-- all dash characters (general category Pd),
minus U+2212
U+002F / <-- fraction slash U+2044,
division slash U+2215
U+003A : <-- ratio U+2236
U+003C < <-- single left-pointing angle quotation mark U+2039,
left-pointing angle bracket U+2329,
left angle bracket U+3008
U+003E > <-- single right-pointing angle quotation mark U+203A,
right-pointing angle bracket U+232A,
right angle bracket U+3009
U+005C \ <-- set minus U+2216
U+005E ^ <-- modifier letter up arrowhead U+02C4,
modifier letter circumflex accent U+02C6,
caret U+2038,
up arrowhead U+2303
U+005F _ <-- all connector characters (general category Pc),
modifier letter low macron U+02CD
U+0060 ` <-- modifier letter grave accent U+02CB
U+007C | <-- divides U+2223
U+007E ~ <-- tilde operator U+223C
@see http://www.unicode.org/reports/tr15/ (UAX#15 Normalization) @see http://www.unicode.org/reports/tr29/ (UAX#29 Grapheme Clusters) @see http://www.unicode.org/reports/tr31/ (UAX#31 Identifiers) @see https://github.com/JuliaStrings/utf8proc
utf8proc_map(In, Options) in the C
API.
compat).nlf2lf, paragraph and line separators become U+000A as
well.compose or decompose.'Strasse' written with U+00DF (LATIN SMALL LETTER SHARP S)
maps to 'strasse', and U+FB03 (LATIN SMALL LIGATURE FFI)
maps to 'ffi'.This predicate is a thin wrapper over utf8proc's property struct, so its vocabulary matches the utf8proc documentation. In the modes (+,?) and (-,?) the predicate enumerates properties for the given code (or the code for the given property); in (+,+) it is a deterministic test.
Supported properties:
cc, cf, cn,
co, cs, ll, lm, lo, lt, lu, mc, me, mn,
nd, nl, no, pc, pd, pe, pf, pi, po, ps,
sc, sk, sm, so, zl, zp, zs.
When querying, the single capital letter of a subcategory stands for all
its subcategories; e.g.
?- unicode_property(0'A, category('L')).
true.
l, lre, lro, r, al,
rle, rlo, pdf, en, es, et, an, cs, nsm,
bn, b, s, ws, on.true if the character is mirrored for bidi (parentheses,
brackets, math operators, ...).font, nobreak,
initial, medial, final, isolated, circle, super,
sub, vertical, wide, narrow, small, square,
fraction, compat. Fails when there is no
decomposition.true if the character is a "default ignorable" code point.start,
other, cr, lf, control, extend, l, v, t,
lv, lvt, regional_indicator, spacingmark, prepend,
zwj, extended_pictographic, e_zwg.true if the character has East-Asian Ambiguous width ---
normally one column, but two in a legacy CJK context.unicode_property(0'A, uppercase(_))
fails because 'A' is already upper-case). For characters
whose case mapping produces more than one code point (e.g. U+00DF LATIN
SMALL LETTER SHARP S maps to "SS"), use unicode_map/3
with the [casefold] option or
unicode_casefold/2 for a
full string-level transformation.none, linker, consonant, extend.
Used by the grapheme-cluster-break algorithm for Devanagari, Bengali,
etc.e + U+0301 are both one grapheme, an
emoji ZWJ sequence such as MAN + ZWJ + WOMAN + ZWJ + GIRL
is one grapheme, and a regional-indicator pair (e.g. U+1F1F3 U+1F1F1,
rendered as the Dutch flag) is one grapheme.
In the forward mode (+Atom, ?Graphemes), Atom is decomposed into a list of atoms, each covering one cluster. In the reverse mode (?Atom, +Graphemes), the elements of Graphemes are concatenated into Atom. Both arguments instantiated means both modes run and the result must agree.
?- atom_codes(A, [0'c, 0'a, 0'f, 0'e, 0x0301]), atom_graphemes(A, Gs). Gs = [c, a, f, G], atom_codes(G, [0'e, 0x0301]). ?- atom_graphemes(A, [a, b, c]). A = abc.
'15.1.0'.