GroteTrap 0.4 → 0.5

raw patch · 2 files changed

+19/−1 lines, 2 files

Files

• GroteTrap.cabal +2/−1
• Language/GroteTrap/Util.hs +17/−0

@@ -1,5 +1,5 @@ Name:           GroteTrap-Version:        0.4+Version:        0.5 Synopsis:       Parser and selection library for expression languages. Description:    Allows quick definition of expression languages. You get a parser for free, as well as conversion from text selection to tree selection and back. Homepage:       http://www.haskell.org/haskellwiki/GroteTrap@@ -24,5 +24,6 @@                     Language.GroteTrap.Lexer                     Language.GroteTrap.Unparse                     Language.GroteTrap.ShowTree+                    Language.GroteTrap.Util   Other-Modules:    Language.GroteTrap.ParseTree                     Language.GroteTrap.Parser

@@ -0,0 +1,17 @@+-- | Utility functions.+--+-- This module re-exports module Control.Monad.Error so that 'fromError' can be used as @Monad m => m a -> a@.+module Language.GroteTrap.Util (fromError, run, module Control.Monad.Error) where++import Text.ParserCombinators.Parsec+import Control.Monad.Error ()++-- | Either returns the value or throws an exception.+fromError :: Either String a -> a+fromError = either error id++-- | @run sourceName p input@ runs the specified parser on the input, returning the result in a monad.+run :: Monad m => String -> GenParser tok () a -> [tok] -> m a+run name p input = case runParser p () name input of+  Left err  -> fail ("parse error at " ++ show err)+  Right v   -> return v