parser2: add function definition, integer patterns, line comments

parser2.hs

@@ -1,11 +1,15 @@
 {-# Language TemplateHaskell, QuasiQuotes, FlexibleContexts #-}
 
-import Text.Peggy
+import Text.Peggy hiding (space)
 import AST
 
 [peggy|
 top :: [AST] = statements !.
 
+lineComment :: () = '--' (!'\n' .)* '\n' { () }
+
+space :: () = [ \r\n\t] { () } / lineComment
+
 statements :: [AST]
   = statement+
 
@@ -17,11 +21,20 @@ args :: AST
   / expr? { case $1 of
   				Just x -> x
   				Nothing -> UnitConst }
+pattern :: Pattern
+  = integer { IntP $1 }
+
+funpattern :: Pattern
+  = pattern ("," pattern)+ { TupleP ($1 : $2) }
+  / pattern? { case $1 of
+  					Just x -> x
+  					Nothing -> UnitP }
 
 expr :: AST
   = expr "(" args ")" { Call $1 $2 }
   / expr "+" fact { Add $1 $2 }
   / expr "-" fact { Sub $1 $2 }
+  / identifier "(" funpattern ")" "->" expr { Defun $1 (Lambda [($2, $3)]) }
   / fact
 
 fact :: AST
@@ -31,13 +44,13 @@ fact :: AST
 
 term :: AST
   = "(" expr ")"
-  / number { IntConst $1 }
+  / integer { IntConst $1 }
   / identifier { Var $1 }
 
 identifier ::: String
   = [a-zA-Z_] [a-zA-Z0-9_'?!]* { $1 : $2 }
 
-number ::: Integer
+integer ::: Integer
   = [1-9] [0-9]* { read ($1 : $2) }
 |]