Add homework 3 solution for CS325

code/cs325-langs/src/CommonParsing.hs

@@ -8,7 +8,7 @@ import Text.Parsec.Combinator
 type Parser a b = Parsec String a b
 
 kw :: String -> Parser a ()
-kw s = string s $> ()
+kw s = try $ string s <* spaces $> ()
 
 kwIf :: Parser a ()
 kwIf = kw "if"
@@ -19,6 +19,12 @@ kwThen = kw "then"
 kwElse :: Parser a ()
 kwElse = kw "else"
 
+kwElsif :: Parser a ()
+kwElsif = kw "elsif"
+
+kwWhile :: Parser a ()
+kwWhile = kw "while"
+
 kwState :: Parser a ()
 kwState = kw "state"
 
@@ -31,6 +37,21 @@ kwCombine = kw "combine"
 kwRand :: Parser a ()
 kwRand = kw "rand"
 
+kwFunction :: Parser a ()
+kwFunction = kw "function"
+
+kwSorted :: Parser a ()
+kwSorted = kw "sorted"
+
+kwLet :: Parser a ()
+kwLet = kw "let"
+
+kwTraverser :: Parser a ()
+kwTraverser = kw "traverser"
+
+kwReturn :: Parser a ()
+kwReturn = kw "return"
+
 op :: String -> op -> Parser a op
 op s o = string s $> o
 
@@ -47,6 +68,9 @@ var reserved =
         then fail "Can't use reserved keyword as identifier"
         else return name
 
+list :: Char -> Char -> Char -> Parser a b -> Parser a [b]
+list co cc cd pe = surround co cc $ sepBy pe (char cd >> spaces)
+
 surround :: Char -> Char -> Parser a b -> Parser a b
 surround c1 c2 pe =
     do