hatt 1.3.1 → 1.4.0

raw patch · 4 files changed

+23/−18 lines, 4 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• README.md +8/−4
• hatt.cabal +1/−1
• src/Data/Logic/Propositional/Parser.hs +13/−12
• src/hatt.hs +1/−1

@@ -23,10 +23,7 @@ ----------------------  The following are all valid expression forms which can be parsed by Hatt, where-ϕ and ψ are metalinguistic variables standing in for any valid expression. The-parser isn't as smart about parentheses as it could be, so you have to follow-these rules quite literally. This shouldn't be a great hardship, but it does-mean that, for example, while `(A -> B)` is a valid expression, `A -> B` isn't.+ϕ and ψ are metalinguistic variables standing in for any valid expression.  * Variables: `P`, `Q`, `a`, `b` etc.---basically anything in the character   class `[a-zA-Z]`@@ -35,6 +32,13 @@ * Disjunction: `(ϕ | ψ)` * Conditional: `(ϕ -> ψ)` * Biconditional: `(ϕ <-> ψ)`++For top-level formulae where the primary connective is a binary one, parentheses+are not required. For example, the expression `a | b` is valid and will be+parsed correctly.++There is currently no support for operator precedence, so nested expressions+must be parenthesised correctly for the parser to make sense of them.   Using the `hatt` command-line program

@@ -1,5 +1,5 @@ Name:               hatt-Version:            1.3.1+Version:            1.4.0  Synopsis:           A truth table generator for classical propositional logic. Description:        Hatt is a command-line program which prints truth tables

@@ -8,7 +8,7 @@ import Data.Logic.Propositional.Core (Expr (..))  import Text.ParserCombinators.Parsec-    (char, choice, eof, oneOf, parse, spaces, string)+    ((<|>), char, choice, eof, letter, parse, spaces, string, try)  import Text.ParserCombinators.Parsec.Error (ParseError) import Text.ParserCombinators.Parsec.Pos (SourceName)@@ -36,7 +36,7 @@  statement :: GenParser Char st Expr statement = do spaces-               x <- expr+               x <- try binary <|> expr                spaces                eof                return x@@ -45,33 +45,34 @@ expr = choice [binaryP, negation, variable]  variable :: GenParser Char st Expr-variable = do c <- oneOf variableChars+variable = do c <- letter               return $ Variable [c]  negation :: GenParser Char st Expr negation = do char '~'+              spaces               x <- expr               return $ Negation x  binaryP :: GenParser Char st Expr binaryP = do char '('+             spaces              x <- binary+             spaces              char ')'              return x  binary :: GenParser Char st Expr binary = do x1 <- expr             spaces-            s  <- choice [string "&", string "|", string "->", string "<->"]+            s  <- choice $ map string ["&", "|", "->", "<->"]             spaces             x2 <- expr             return $ connective s x1 x2   where-    connective "&"   = Conjunction-    connective "|"   = Disjunction-    connective "->"  = Conditional-    connective "<->" = Biconditional-    connective _     = error "Impossible case"--variableChars :: String-variableChars = ['a'..'z'] ++ ['A'..'Z']+    connective c = case c of+      "&"   -> Conjunction+      "|"   -> Disjunction+      "->"  -> Conditional+      "<->" -> Biconditional+      _     -> error "Impossible case"

@@ -31,7 +31,7 @@   , interactive = False &= help "Enter interactive mode"   , pretty      = False &= help "Use Unicode logic symbols"   , coloured    = False &= help "Use colour-coded symbols"-  } &= summary "Hatt 1.3.1, (c) Benedict Eastaugh 2011"+  } &= summary "Hatt 1.4.0, (c) Benedict Eastaugh 2011"     &= program "hatt"  main :: IO ()