-- re2hs $INPUT -o $OUTPUT
{-# OPTIONS_GHC -Wno-unused-record-wildcards #-}
{-# LANGUAGE OverloadedStrings #-}
import Control.Monad (when)
import Data.ByteString (ByteString, index)
data State = State {
-- Final tag bindings available in semantic action.
%{svars format = "\n@@ :: !Int,"; %}
-- Intermediate tag bindings used by the lexer (must be autogenerated).
%{stags format = "\n@@ :: !Int,"; %}
_yyinput :: !ByteString,
_yycursor :: !Int,
_yymarker :: !Int
}
data SemVer = SemVer {
major :: !Int,
minor :: !Int,
patch :: !Int
} deriving (Eq)
s2n :: ByteString -> Int -> Int -> Int
s2n s i j = f i 0 where
f k n = if k >= j then n else f (k + 1) (n * 10 + (fromIntegral (index s k) - 48))
%{
re2c:YYFN = ["parse;Maybe SemVer", "State{..};State"];
re2c:tags = 1;
re2c:yyfill:enable = 0;
num = [0-9]+;
@_1 num @_2 "." @_3 num @_4 ("." @_5 num)? [\x00] {
Just SemVer {
re2c version: 4.1~8baaca577
Select example "haskell/submatch/01_stags.re"