private void Unify(ref IfsType t1, ref IfsType t2, fsScope scope)
{
if (t1.Name == "identity")
{
t1 = t2;
return;
}
if (t2.Name == "identity")
{
t2 = t1;
return;
}
IfsType t1Pruned = Prune(t1);
IfsType t2Pruned = Prune(t2);
if (t1Pruned.Name != "composite")
{
t1 = t1Pruned;
}
if (t2Pruned.Name != "composite")
{
t2 = t2Pruned;
}
if (t1 is fsTypeVar)
{
if (!t1.Equals(t2))
{
if (OccursInType(t1, t2))
{
throw new Exception("Recursive unification");
}
if (t2.Name == "composite")
{
(t1 as fsTypeVar).Instance = t2;
}
else
{
t1 = t2;
}
}
}
else if(t1 is fsType && t2 is fsTypeVar)
{
UnifyWrapper(ref t2, ref t1, scope);
}
else if (t1 is fsType && t2 is fsType)
{
fsType type1 = t1 as fsType;
fsType type2 = t2 as fsType;
if (type1.Name == "composite")
{
if (type2.Name != "composite")
{
UnifyWrapper(ref t2, ref t1, scope);
return;
}
List<IfsType> commonTypes = new List<IfsType>();
for (int i = 0; i < type1.Types.Count; i++)
{
for (int j = 0; j < type2.Types.Count; j++)
{
if (type1.Types[i].Equals(type2.Types[j]))
{
commonTypes.Add(type1.Types[i]);
}
}
}
if (commonTypes.Count < 1)
{
throw new Exception($"Cannot unify types {type1.Name} and {type2.Name}");
}
else if (commonTypes.Count == 0)
{
t1 = t2 = commonTypes[0];
}
else
{
fsTypeVar commonType = new fsTypeVar();
commonType.Instance = fsType.GetCompositeType(commonTypes);
t1 = t2 = commonType;
}
return;
}
if (type2.Name == "composite")
{
for (int i = 0; i < type2.Types.Count; i++)
{
if (type1.Equals(type2.Types[i]))
{
t1 = t2 = type1;
return;
}
}
throw new Exception($"Cannot unify types {type1.Name} and {type2.Name}");
}
if (!type1.Equals(type2))
{
throw new Exception($"Cannot unify types {type1.Name} and {type2.Name}");
}
if (type1.Name == "function")
{
if (type1.Types.Count == type2.Types.Count)
{
IfsType returningType = type2.Types[type2.Types.Count - 1];
for (int i = 0; i < type1.Types.Count - 1; i++)
{
IfsType t1Child = type1.Types[i];
IfsType t2Child = type2.Types[i];
string t2NameBeforeUnification = t2Child.Name;
//Changed !!!!!!!
UnifyWrapper(ref t2Child, ref t1Child, scope);
type1.Types[i] = t1Child;
type2.Types[i] = t2Child;
if (returningType.Name == t2NameBeforeUnification)
{
UnifyWrapper(ref returningType, ref t1Child, scope);
type1.Types[i] = returningType;
type2.Types[type2.Types.Count - 1] = t2Child;
}
}
}
else if (type1.Types.Count < type2.Types.Count)
{
int difference = type2.Types.Count - type1.Types.Count;
for (int i = 0; i < type1.Types.Count - 1; i++)
{
IfsType t1Child = type1.Types[i];
IfsType t2Child = type2.Types[i];
string t2NameBeforeUnification = t2Child.Name;
//Changed !!!!!!!
UnifyWrapper(ref t2Child, ref t1Child, scope);
type1.Types[i] = t1Child;
type2.Types[i] = t2Child;
for (int j = difference; j < type2.Types.Count; j++)
{
IfsType bufType = type2.Types[j];
if (bufType.Name == t2NameBeforeUnification)
{
UnifyWrapper(ref t1Child, ref bufType, scope);
type1.Types[i] = bufType;
type2.Types[j] = t2Child;
}
}
}
List<IfsType> rest = type2.Types.GetRange(type1.Types.Count - 1, difference + 1);
type1.Types[type1.Types.Count - 1] = fsType.GetFunctionType(rest);
t1 = t2 = type1;
}
else
{
throw new Exception($"Cannot unify types {type1.Name} and {type2.Name}");
}
}
}
else
{
throw new Exception($"Cannot unify types {t1.Name} and {t2.Name}");
}
}
private IfsType InferFunctionDefnType(ITree node, fsScope scope)
{
fsScope innerScope = new fsScope(scope);
List<IfsType> functionTypes = new List<IfsType>();
string funcName = GetChildByType(node, fsharp_ssParser.NAME).GetChild(0).Text;
ITree args = GetChildByType(node, fsharp_ssParser.ARGS);
List<string> argsNames = new List<string>();
for (int i = 0; i < args.ChildCount; i++)
{
ITree arg = args.GetChild(i);
IfsType argType;
if (arg.ChildCount > 0)
{
ITree annotatedArgTypeNode = arg.GetChild(0);
argType = new fsType(annotatedArgTypeNode.Text, null);
}
else
{
argType = new fsTypeVar();
}
argsNames.Add(arg.Text);
innerScope.AddVar(arg.Text, argType);
innerScope.SetVarInfo(arg.Text, ScopePositionType.functionArg);
}
fsDerFuncInfo funcInfo = new fsDerFuncInfo(funcName, argsNames, 0, 0,
enteredFunctionsNames[enteredFunctionsNames.Count - 1]);
if (funcName != "main")
{
enteredFunctionsNames.Add(funcName);
}
functionsInfos.Add(funcName, funcInfo);
node.AddChild(new fsTreeNode(funcInfo));
if (GetChildByType(node, fsharp_ssParser.REC) != null)
{
innerScope.AddFunction(funcName, fsType.GetIdentityType(innerScope, argsNames));
innerScope.SetVarInfo(funcName, ScopePositionType.functionClass);
}
IfsType bodyType = Analyse(GetChildByType(node, fsharp_ssParser.BODY), innerScope);
ITree annotatedReturningTypeNode = GetChildByType(node, fsharp_ssParser.TYPE);
if (annotatedReturningTypeNode != null && annotatedReturningTypeNode.ChildCount > 0)
{
IfsType annotatedReturningType = new fsType(annotatedReturningTypeNode.GetChild(0).Text, null);
UnifyWrapper(ref bodyType, ref annotatedReturningType, innerScope);
}
for (int i = 0; i < argsNames.Count; i++)
{
functionTypes.Add(innerScope.GetVarType(argsNames[i]));
}
functionTypes.Add(bodyType);
fsType functionType = fsType.GetFunctionType(functionTypes);
enteredFunctionsNames.RemoveAt(enteredFunctionsNames.Count - 1);
return functionType;
}