Your code is mostly fine, the reason it's only compiling, is due to Nim having
a much stricter type system. For other visitors this is the error message is:
in.nim(3, 34) Error: type mismatch: got but expected 'cuchar = Char'
Run
You're probably better off not using the types prefixed by C, those are mostly
meant for compability.
This is how I would translate your function into more idiomatic Nim:
proc utf8str_codepoint_len*(s: string, utf8len: int): int =
const
m4 = 128'u8 + 64 + 32 + 16
m3 = 128'u8 + 64 + 32
m2 = 128'u8 + 64
var i = 0
while i < utf8len:
# in Nim char and uint8/byte are separate types, with the former being
only used to represent 8 bit
# characters and thus arithmetic functions aren't defined for neither
it nor cchar.
var c = uint8(s[i])
if (c and m4) == m4:
i += 3
elif (c and m3) == m3:
i += 2
elif (c and m2) == m2:
i += 1
inc result # result is the implicit return value that is like all
unassigned variables in Nim set to 0 in the beginning
Run
