Availability:C-language interface function
int PL_is_id_start(int
chr)
int PL_is_id_continue(int
chr)
int PL_is_uppercase(int
chr)
int PL_is_decimal(int
chr)
int PL_is_layout(int
chr)Unicode classification predicates. Each returns non-zero iff the 32-bit
code point chr carries the corresponding property as defined
by the data files in src/Unicode/ and consulted by the
Prolog reader. Provided so foreign extensions and embedded toolkits
(notably xpce) classify code points exactly as SWI-Prolog does, locale-
independently. id_start and id_continue follow
Prolog's identifier syntax (close to UAX #31 XID_Start /
XID_Continue, adjusted for Prolog). layout matches the
reader's whitespace set (white_space/1 in
src/Unicode/derived_core_properties.pl).