Maps over Unicode characters.
map ?eq f m
and mapi ?eq f m
: Similar to map
and mapi
in stdlib Map, but if the map m'
is returned, it is only guaranteed
that eq (find u m') (f (find u m ))
is true for map
and
eq (find u m') (f u (find u m ))
is true for mapi
. If eq
is
not specified, structural equality is used.
fold_range f m x
is equivalent to
f u_(2n) u_(2n+1) v_n (... (f u_1 u_2 v_1 x))
where all characters in
the range u_(2k)
-u_(2k+1)
are mapped to v_k
and
u_1
< u_3
< ... in code point order.
For each range u_(2k)
-u_(2k+1)
is separated by a character
which is not mapped to v_k
.