diff options
Diffstat (limited to 'src/Main.hs')
| -rw-r--r-- | src/Main.hs | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/Main.hs b/src/Main.hs index bcb1f00..61dc3bc 100644 --- a/src/Main.hs +++ b/src/Main.hs @@ -37,6 +37,33 @@ splitOn spl (x:xs) | otherwise = let (r : rs) = splitOn spl xs in (x:r) : rs +usageString :: String +usageString = + "\x1B[1mMeta-commands\x1B[0m\n\ + \ env -- Show the current environment\n\ + \ exit -- Exit program immediately\n\ + \ undo -- Undo last operation\n\ + \ focus \x1B[4mx\x1B[0m -- Watch and operate on given variable\n\ + \ focus -- Unfocus currently focused variable\n\ + \ log -- Print list of commands that reproduces current environment\n\ + \ help -- Show this help\n\ + \\n\ + \\x1B[1mExpression rewrite commands\x1B[0m\n\ + \These commands operate on the currently-focused expression.\n\ + \ rew \x1B[4mx\x1B[0m -- Replaces occurrences of \x1B[4mx\x1B[0m with its value\n\ + \ beta -- Applies some beta-reductions ((\\x -> M) y => M[y/x])\n\ + \ eta -- Applies some eta-reductions ((\\x -> f x) => f)\n\ + \ case -- Evaluates case statements\n\ + \ case! -- Evaluates case statements, choosing first hit if multiple branches unify\n\ + \ etacase -- If all case branches are the same as their patterns, remove case statement\n\ + \ casecase -- case (case x of {A->a;B->b}) of {C->c;D->d} \n\ + \ => case x of {A->case a of {C->c;D->d}; B->case b of {C->c;D->d}}\n\ + \ repeat \x1B[4mcmd\x1B[0m -- Repeat \x1B[4mcmd\x1B[0m until no change occurs\n\ + \\n\ + \To evaluate a rewrite command on an unfocused variable, use:\n\ + \ action \x1B[4mx\x1B[0m \x1B[4mcmd\x1B[0m -- Evaluate \x1B[4mcmd\x1B[0m on variable \x1B[4mx\x1B[0m" + + data AppState = AppState { asCtx :: Context, asFocus :: Maybe Name } deriving (Show) @@ -64,6 +91,7 @@ data UserCmd = UCCmd Cmd | CUnFocus | CFocus Name | CLog + | CHelp deriving (Show) instance Pretty Action where @@ -145,6 +173,7 @@ applyUserCmd appstate = \case CLog -> do mapM_ (putStrLn . pretty) $ map fst (reverse $ cStack (asCtx appstate)) return (Right (Just appstate)) + CHelp -> putStrLn usageString >> return (Right (Just appstate)) applyUserCmds :: AppState -> [UserCmd] -> IO (Either String (Maybe AppState)) applyUserCmds appstate [] = return (Right (Just appstate)) @@ -200,6 +229,7 @@ parseCmd ["env"] = Right CShowEnv parseCmd ["focus"] = Right CUnFocus parseCmd ["focus", name] = Right (CFocus name) parseCmd ["log"] = Right CLog +parseCmd ["help"] = Right CHelp parseCmd ["rew", func] = Right (UCCmd (CRewrite func)) parseCmd ["beta"] = Right (UCCmd CBeta) parseCmd ["eta"] = Right (UCCmd CEta) |