Fix conflict

Grammar.cf

@@ -6,7 +6,7 @@ EId.  Exp3 ::= Ident   ;
 EInt. Exp3 ::= Integer ;
 EApp. Exp2 ::= Exp2 Exp3 ;
 EAdd. Exp1 ::= Exp1 "+" Exp2 ;
-EAbs. Exp  ::= "\\" Ident "->" Exp ;
+EAbs. Exp  ::= "\\" Ident "." Exp ;
 
 coercions Exp 3 ;
 

src/Grammar/Doc.txt

@@ -0,0 +1,56 @@
+The Language Grammar
+BNF Converter
+
+
+%Process by txt2tags to generate html or latex
+
+
+
+This document was automatically generated by the //BNF-Converter//. It was generated together with the lexer, the parser, and the abstract syntax module, which guarantees that the document matches with the implementation of the language (provided no hand-hacking has taken place).
+
+==The lexical structure of Grammar==
+===Identifiers===
+Identifiers //Ident// are unquoted strings beginning with a letter,
+followed by any combination of letters, digits, and the characters ``_ '``
+reserved words excluded.
+
+
+===Literals===
+Integer literals //Integer// are nonempty sequences of digits.
+
+
+
+
+===Reserved words and symbols===
+The set of reserved words is the set of terminals appearing in the grammar. Those reserved words that consist of non-letter characters are called symbols, and they are treated in a different way from those that are similar to identifiers. The lexer follows rules familiar from languages like Haskell, C, and Java, including longest match and spacing conventions.
+
+The reserved words used in Grammar are the following:
+  | ``main`` |  |  |
+
+The symbols used in Grammar are the following:
+  | = | + | \ | .
+  | ( | ) |  |
+
+===Comments===
+Single-line comments begin with --.Multiple-line comments are  enclosed with {- and -}.
+
+==The syntactic structure of Grammar==
+Non-terminals are enclosed between < and >.
+The symbols -> (production),  **|**  (union)
+and **eps** (empty rule) belong to the BNF notation.
+All other symbols are terminals.
+
+  | //Program// | -> | ``main`` ``=`` //Exp//
+  | //Exp3// | -> | //Ident//
+  |  |  **|**  | //Integer//
+  |  |  **|**  | ``(`` //Exp// ``)``
+  | //Exp2// | -> | //Exp2// //Exp3//
+  |  |  **|**  | //Exp3//
+  | //Exp1// | -> | //Exp1// ``+`` //Exp2//
+  |  |  **|**  | //Exp2//
+  | //Exp// | -> | ``\`` //Ident// ``.`` //Exp//
+  |  |  **|**  | //Exp1//
+
+
+
+%% File generated by the BNF Converter (bnfc 2.9.4.1).

src/Grammar/Print.hs

@@ -0,0 +1,153 @@
+-- File generated by the BNF Converter (bnfc 2.9.4.1).
+
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE LambdaCase #-}
+#if __GLASGOW_HASKELL__ <= 708
+{-# LANGUAGE OverlappingInstances #-}
+#endif
+
+-- | Pretty-printer for Grammar.
+
+module Grammar.Print where
+
+import Prelude
+  ( ($), (.)
+  , Bool(..), (==), (<)
+  , Int, Integer, Double, (+), (-), (*)
+  , String, (++)
+  , ShowS, showChar, showString
+  , all, elem, foldr, id, map, null, replicate, shows, span
+  )
+import Data.Char ( Char, isSpace )
+import qualified Grammar.Abs
+
+-- | The top-level printing method.
+
+printTree :: Print a => a -> String
+printTree = render . prt 0
+
+type Doc = [ShowS] -> [ShowS]
+
+doc :: ShowS -> Doc
+doc = (:)
+
+render :: Doc -> String
+render d = rend 0 False (map ($ "") $ d []) ""
+  where
+  rend
+    :: Int        -- ^ Indentation level.
+    -> Bool       -- ^ Pending indentation to be output before next character?
+    -> [String]
+    -> ShowS
+  rend i p = \case
+      "["      :ts -> char '[' . rend i False ts
+      "("      :ts -> char '(' . rend i False ts
+      "{"      :ts -> onNewLine i     p . showChar   '{'  . new (i+1) ts
+      "}" : ";":ts -> onNewLine (i-1) p . showString "};" . new (i-1) ts
+      "}"      :ts -> onNewLine (i-1) p . showChar   '}'  . new (i-1) ts
+      [";"]        -> char ';'
+      ";"      :ts -> char ';' . new i ts
+      t  : ts@(s:_) | closingOrPunctuation s
+                   -> pending . showString t . rend i False ts
+      t        :ts -> pending . space t      . rend i False ts
+      []           -> id
+    where
+    -- Output character after pending indentation.
+    char :: Char -> ShowS
+    char c = pending . showChar c
+
+    -- Output pending indentation.
+    pending :: ShowS
+    pending = if p then indent i else id
+
+  -- Indentation (spaces) for given indentation level.
+  indent :: Int -> ShowS
+  indent i = replicateS (2*i) (showChar ' ')
+
+  -- Continue rendering in new line with new indentation.
+  new :: Int -> [String] -> ShowS
+  new j ts = showChar '\n' . rend j True ts
+
+  -- Make sure we are on a fresh line.
+  onNewLine :: Int -> Bool -> ShowS
+  onNewLine i p = (if p then id else showChar '\n') . indent i
+
+  -- Separate given string from following text by a space (if needed).
+  space :: String -> ShowS
+  space t s =
+    case (all isSpace t', null spc, null rest) of
+      (True , _   , True ) -> []              -- remove trailing space
+      (False, _   , True ) -> t'              -- remove trailing space
+      (False, True, False) -> t' ++ ' ' : s   -- add space if none
+      _                    -> t' ++ s
+    where
+      t'          = showString t []
+      (spc, rest) = span isSpace s
+
+  closingOrPunctuation :: String -> Bool
+  closingOrPunctuation [c] = c `elem` closerOrPunct
+  closingOrPunctuation _   = False
+
+  closerOrPunct :: String
+  closerOrPunct = ")],;"
+
+parenth :: Doc -> Doc
+parenth ss = doc (showChar '(') . ss . doc (showChar ')')
+
+concatS :: [ShowS] -> ShowS
+concatS = foldr (.) id
+
+concatD :: [Doc] -> Doc
+concatD = foldr (.) id
+
+replicateS :: Int -> ShowS -> ShowS
+replicateS n f = concatS (replicate n f)
+
+-- | The printer class does the job.
+
+class Print a where
+  prt :: Int -> a -> Doc
+
+instance {-# OVERLAPPABLE #-} Print a => Print [a] where
+  prt i = concatD . map (prt i)
+
+instance Print Char where
+  prt _ c = doc (showChar '\'' . mkEsc '\'' c . showChar '\'')
+
+instance Print String where
+  prt _ = printString
+
+printString :: String -> Doc
+printString s = doc (showChar '"' . concatS (map (mkEsc '"') s) . showChar '"')
+
+mkEsc :: Char -> Char -> ShowS
+mkEsc q = \case
+  s | s == q -> showChar '\\' . showChar s
+  '\\' -> showString "\\\\"
+  '\n' -> showString "\\n"
+  '\t' -> showString "\\t"
+  s -> showChar s
+
+prPrec :: Int -> Int -> Doc -> Doc
+prPrec i j = if j < i then parenth else id
+
+instance Print Integer where
+  prt _ x = doc (shows x)
+
+instance Print Double where
+  prt _ x = doc (shows x)
+
+instance Print Grammar.Abs.Ident where
+  prt _ (Grammar.Abs.Ident i) = doc $ showString i
+instance Print Grammar.Abs.Program where
+  prt i = \case
+    Grammar.Abs.Program exp -> prPrec i 0 (concatD [doc (showString "main"), doc (showString "="), prt 0 exp])
+
+instance Print Grammar.Abs.Exp where
+  prt i = \case
+    Grammar.Abs.EId id_ -> prPrec i 3 (concatD [prt 0 id_])
+    Grammar.Abs.EInt n -> prPrec i 3 (concatD [prt 0 n])
+    Grammar.Abs.EApp exp1 exp2 -> prPrec i 2 (concatD [prt 2 exp1, prt 3 exp2])
+    Grammar.Abs.EAdd exp1 exp2 -> prPrec i 1 (concatD [prt 1 exp1, doc (showString "+"), prt 2 exp2])
+    Grammar.Abs.EAbs id_ exp -> prPrec i 0 (concatD [doc (showString "\\"), prt 0 id_, doc (showString "."), prt 0 exp])

src/Interpreter.hs

@@ -39,7 +39,7 @@ eval cxt = \case
 
   EInt i    -> pure $ VInt i
 
-  --  γ     ⊢ e  ⇓ let δ in λx → f
+  --  γ     ⊢ e  ⇓ let δ in λx. f
   --  γ     ⊢ e₁ ⇓ v
   --  δ,x=v ⊢ f  ⇓ v₁
   --  ------------------------------
@@ -54,7 +54,7 @@ eval cxt = \case
 
   --
   --  -----------------------------
-  --  γ ⊢ λx → f ⇓ let γ in λx → f
+  --  γ ⊢ λx. f ⇓ let γ in λx. f
 
   EAbs x e  -> pure $ VClosure cxt x e
 

test_program

@@ -2,4 +2,4 @@
 
 
 
-main = (\x -> x + x + 3) ((\x -> x) 2)
+main = (\x. x + x + 3) ((\x. x) 2)