From fa405e7e46eb20cc1ad49694a166273661dfae0c Mon Sep 17 00:00:00 2001
From: Neil Brown <neil@twistedsquare.com>
Date: Sun, 2 Sep 2007 16:50:12 +0000
Subject: [PATCH] Rain: added a pass to transform functions into the occam form

---
 RainPassTest.hs | 23 +++++++++++++++++++++++
 RainPasses.hs   | 20 ++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/RainPassTest.hs b/RainPassTest.hs
index e4dc7eb..c70c952 100644
--- a/RainPassTest.hs
+++ b/RainPassTest.hs
@@ -472,6 +472,27 @@ testRangeRepPass1 = testPass "testRangeRepPass1" exp (transformRangeRep orig) (r
     orig = A.ExprConstr m $ A.RangeConstr m (intLiteral 1) (intLiteral 0)
     exp = A.Literal m (A.Array [A.Dimension 0] A.Int) $ A.ArrayLiteral m []
 
+--TODO consider/test pulling up the definitions of variables involved in return statements in functions
+
+-- | Test a fairly standard function:
+testTransformFunction0 :: Test
+testTransformFunction0 = testPass "testTransformFunction0" exp (transformFunction orig) (return ())
+  where
+    orig = A.Specification m (procName "id") $
+        A.Function m A.PlainSpec [A.Byte] [A.Formal A.ValAbbrev A.Byte (simpleName "x")] $
+          (A.OnlyP m $ A.Seq m $ A.Several m [A.OnlyEL m $ A.ExpressionList m [exprVariable "x"]])
+    exp = tag3 A.Specification DontCare (procNamePattern "id") $
+        tag5 A.Function DontCare A.PlainSpec [A.Byte] [tag3 A.Formal A.ValAbbrev A.Byte (simpleNamePattern "x")] $
+          tag3 A.ProcThen DontCare (tag2 A.Seq DontCare $ tag2 A.Several DontCare ([] :: [A.Structured])) $
+            tag2 A.OnlyEL DontCare $ tag2 A.ExpressionList DontCare [exprVariablePattern "x"]
+
+-- | Test a function without a return as the final statement:
+testTransformFunction1 :: Test
+testTransformFunction1 = testPassShouldFail "testTransformFunction1" (transformFunction orig) (return ())
+  where
+    orig = A.Specification m (procName "brokenid") $
+        A.Function m A.PlainSpec [A.Byte] [A.Formal A.ValAbbrev A.Byte (simpleName "x")] $
+          (A.OnlyP m $ A.Seq m $ A.Several m [])
 
 ---Returns the list of tests:
 tests :: Test
@@ -507,6 +528,8 @@ tests = TestList
    ,testParamPass8
    ,testRangeRepPass0
    ,testRangeRepPass1
+   ,testTransformFunction0
+   ,testTransformFunction1
  ]
 
 
diff --git a/RainPasses.hs b/RainPasses.hs
index e24075c..a9ad197 100644
--- a/RainPasses.hs
+++ b/RainPasses.hs
@@ -47,6 +47,8 @@ rainPasses =
          --depends on uniquifyAndResolveVars and recordInfNameTypes, and should be done after transformEachRange
        ,("Convert simple Rain range constructors into more general array constructors",transformRangeRep)
          --must be done after transformEachRange
+       ,("Transform Rain functions into the occam form",transformFunction)
+         --must be done after transformEach, depends on uniquifyAndResolveVars and recordInfNameTypes
      ]
 
 -- | A pass that transforms all instances of 'A.Int' into 'A.Int64'
@@ -301,3 +303,21 @@ transformRangeRep = everywhereM (mkM transformRangeRep')
                           (A.Literal m A.Int (A.IntLiteral m $ show count))
                         ) (A.ExprVariable m $ A.Variable m rep)
     transformRangeRep' s = return s
+
+transformFunction :: Data t => t -> PassM t
+transformFunction = everywhereM (mkM transformFunction')
+  where
+    transformFunction' :: A.SpecType -> PassM A.SpecType
+    transformFunction' (A.Function m specMode types params body)
+      = case body of 
+          (A.OnlyP _ (A.Seq m' (A.Several m'' statements))) ->
+            if (null statements)
+              then dieP m "Functions must not have empty bodies"
+              else case (last statements) of 
+                ret@(A.OnlyEL {}) -> return $
+                  (A.Function m specMode types params 
+                    (A.ProcThen m' (A.Seq m' (A.Several m'' (init statements))) ret)
+                  )
+                _ -> dieP m "Functions must have a return statement as their last statement"
+          _ -> dieP m "Functions must have seq[uential] bodies"
+    transformFunction' s = return s