diff options
Diffstat (limited to 'src/Thue/Interpreter.hs')
| -rw-r--r-- | src/Thue/Interpreter.hs | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/src/Thue/Interpreter.hs b/src/Thue/Interpreter.hs index 7c41718..28aff93 100644 --- a/src/Thue/Interpreter.hs +++ b/src/Thue/Interpreter.hs @@ -24,23 +24,30 @@ thue program = interpret :: ThueState -> [ThueRule] -> StdGen -> IO ThueState -interpret state rules gen = do +interpret state rules gen = let possibleRules = rules `applicableTo` state - ruleToApply = if (possibleRules == []) then (ThueRule "" "") else possibleRules !! num - -- ^ dummy rule if no possible rules apply + ruleToApply = possibleRules !! num (num, gen') = nextInRange 0 (length possibleRules - 1) gen - (before, after) = fromJust (extractInfix (original ruleToApply) state) + in if (possibleRules == []) + then return state + else applyRule ruleToApply state >>= (\x -> interpret x rules gen') - state' <- case (replacement ruleToApply) of - ":::" -> getLine >>= return . toThueState >>= (\x -> return (before ++ x ++ after)) - '~':xs -> return (fromThueState xs) >>= putStr >> return (before ++ after) - x -> return (before ++ x ++ after) +applyRule :: ThueRule -> ThueState -> IO ThueState +applyRule rule state = + let (before, after) = fromJust (extractInfix (original rule) state) - if (possibleRules == []) then return state else interpret state' rules gen' + in case (replacement rule) of + x | x == (tStr ":::") -> + getLine >>= return . toThueState >>= return . (before ++) . (++ after) + + x:xs | x == (tCh '~') -> + putStr (fromThueState xs) >> return (before ++ after) + + x -> return (before ++ x ++ after) |