From: Francis Russell <francis@unchartedbackwaters.co.uk>
Date: Wed, 12 Sep 2012 11:15:00 +0000 (+0100)
Subject: Parse basic assignments.
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=2ffed64e486a5a0ff6a23bd275153b5ba71a0a44;p=francis%2Fofc.git

Parse basic assignments.
---

diff --git a/src/Parsing.hs b/src/Parsing.hs
index 80c313e..e431a23 100644
--- a/src/Parsing.hs
+++ b/src/Parsing.hs
@@ -1,6 +1,7 @@
 module Parsing where
 import Text.Parsec
 import Text.Parsec.Prim
+import Text.Parsec.Expr
 import Text.Parsec.Token
 import Text.Parsec.Language
 import Text.Parsec.Combinator
@@ -8,9 +9,18 @@ import Text.Parsec.Combinator
 data OFL = OFL [OFLDeclaration] deriving Show
 data OFLType = Real | Function | Integer deriving Show
 data OFLIndex = FunctionIndex | SpinIndex | SpatialIndex deriving Show
-data OFLDeclaration = Declaration OFLType [OFLIndex] [String] deriving Show
+data OFLDeclaration = DeclareValues OFLType [OFLIndex] [String] | DeclareIndices OFLIndex [String] deriving Show
 data OFLAssignment = Assign OFLExpression OFLExpression deriving Show
-data OFLExpression = Identifier String | IndexedIdentifier String [String] deriving Show
+data OFLExpression = Identifier String | 
+                     IndexedIdentifier String [String] | 
+                     ConstReal Double |
+                     ConstInteger Integer |
+                     Negate OFLExpression | 
+                     Inner OFLExpression OFLExpression | 
+                     Laplacian OFLExpression | 
+                     Sum OFLExpression String |
+                     Product OFLExpression OFLExpression |
+                     Derivative OFLExpression String deriving Show
 
 oflIndexTypes = ["FunctionIndex", "SpinIndex", "SpatialIndex"]
 oflOperandTypes = ["Real", "Function", "Integer"] 
@@ -33,27 +43,53 @@ TokenParser { reserved = oflReserved
             , commaSep = oflCommaSep
             , brackets = oflBrackets
             , symbol = oflSymbol
+            , parens = oflParens
+            , float = oflFloat
+            , integer = oflInteger
 } = makeTokenParser oflDef
 
+oflOperatorTable = [[Prefix (do { oflSymbol "-"; return (\x -> Negate x)})],
+                    [Infix  (do { oflSymbol "*"; return (\x y -> Product x y) }) AssocLeft]
+                   ]
 
 parseType = foldl1 (<|>) [do { oflReserved $ show t; return t} | t <- [Real, Function, Integer]]
 parseIndex = foldl1 (<|>) [do { oflReserved $ show t; return t} | t <- [FunctionIndex, SpinIndex, SpatialIndex]]
-parseDeclaration = do { valueType <- parseType;
-                        indices <- oflBrackets $ oflCommaSep parseIndex;
-                        names <- oflCommaSep parseIdentifier;
-                        return $ Declaration valueType indices names
-                      }
+parseDeclaration = parseValueDeclaration <|> parseIndexDeclaration
+parseValueDeclaration = do { valueType <- parseType;
+                             indices <- oflBrackets $ oflCommaSep parseIndex;
+                             names <- oflCommaSep parseIdentifier;
+                             return $ DeclareValues valueType indices names
+}
+
+parseIndexDeclaration = do { indexType <- parseIndex;
+                             names <- oflCommaSep parseIdentifier;
+                             return $ DeclareIndices indexType names
+                           }
 
 parseIdentifier = do {identifier <- oflIdentifier; return identifier }
 
-parseAssignment = do { lhs <- parseExpression;
+parseAssignment = do { lhs <- parseIdentifierAccess;
                        oflSymbol "=";
                        rhs <- parseExpression;
                        return $ Assign lhs rhs
                      }
 
-parseExpression = parseIndexedIdentifier <|> parseUnindexedIdentifier
+parseExpression = buildExpressionParser oflOperatorTable parseTerm
+
+parseTerm = do { oflSymbol "laplacian"; operand <- oflParens parseExpression; return $ Laplacian operand } <|>
+            do { oflSymbol "inner"; inner <- oflParens parseInner; return inner} <|>
+            do { oflSymbol "sum"; sum <- oflParens parseSum; return sum} <|>
+            do { oflSymbol "derivative"; derivative <- oflParens parseDerivative; return derivative} <|>
+            do { float <- oflFloat; return $ ConstReal float } <|>
+            do { integer <- oflInteger; return $ ConstInteger integer } <|>
+            oflParens parseExpression <|>
+            parseIdentifierAccess
 
+parseInner = do { e1 <- parseExpression; oflSymbol ","; e2 <- parseExpression; return $ Inner e1 e2}
+parseSum = do { e1 <- parseExpression; oflSymbol ","; index <- parseIdentifier; return $ Sum e1 index}
+parseDerivative = do { e1 <- parseExpression; oflSymbol ","; index <- parseIdentifier; return $ Derivative e1 index}
+                       
+parseIdentifierAccess = parseIndexedIdentifier <|> parseUnindexedIdentifier
 
 parseUnindexedIdentifier = do { identifier <- parseIdentifier; 
                                 return $ Identifier identifier