ref: 75c92428225428c8fde2d015f010e608a0b12f1d
dir: /appl/charon/ctype.m/
Ctype: module
{
PATH: con "/dis/charon/ctype.dis";
# Classify first NCTYPE chars of Unicode into one of
#
# W: whitespace
# D: decimal digit
# L: lowercase letter
# U: uppercase letter
# N: '.' or '-' (parts of certain kinds of names)
# S: '_' (parts of other kinds of names)
# P: printable other than all of above
# C: control other than whitespace
#
# These are separate bits, so can test for, e.g., ctype[c]&(U|L),
# but only one is set for any particular character,
# so can use faster ctype[c]==W too.
W, D, L, U, N, S, P, C: con byte (1<<iota);
NCTYPE: con 256;
ctype: array of byte;
};