public override Type Typecheck(TypecheckingState state)
{
Type = Expression.Typecheck(state);
state.EnterScope();
state.BindVariable(Name, Type);
var type = Recipient.Typecheck(state);
state.ExitScope();
return(type);
}
// public string Name;
public override Type Typecheck(TypecheckingState state)
{
try
{
var type = state.LookupVariable(Name);
return(type);
} catch (TypechekingStateException e)
{
TypeError(e.Message);
}
throw new ImpossibleException();
}
// public string Name;
// public Expression Argument;
public override Type Typecheck(TypecheckingState state)
{
try
{
var fun = state.LookupFunction(Name);
var argumentType = Argument.Typecheck(state);
if (argumentType != fun.ArgumentType)
{
TypeError($"Argument type mismatch in call to {Name}");
}
return(fun.ReturnType);
} catch (TypechekingStateException e)
{
TypeError(e.Message);
}
throw new ImpossibleException();
}
public override Type Typecheck(TypecheckingState state)
{
var type1 = Expression1.Typecheck(state);
var type2 = Expression2.Typecheck(state);
OperandType = type1;
switch (Operator)
{
case BinaryOperator.Add:
if (type1 != Type.NumType && type2 != Type.NumType)
{
TypeError("+ expects number operands");
}
return(Type.NumType);
case BinaryOperator.Sub:
if (type1 != Type.NumType && type2 != Type.NumType)
{
TypeError("- expects number operands");
}
return(Type.NumType);
case BinaryOperator.Eq:
if (type1 != type2)
{
TypeError("== expects operands of the same type");
}
return(Type.BoolType);
case BinaryOperator.Lt:
if (type1 != Type.NumType && type2 != Type.NumType)
{
TypeError("- expects number operands");
}
return(Type.BoolType);
}
throw new ImpossibleException();
}
// public string Name;
// public string ArgumentName;
// public Type ArgumentType;
// public Type ReturnType;
// public Expression Body;
// public Expression Recipient;
public override Type Typecheck(TypecheckingState state)
{
state.EnterScope();
state.BindFunction(Name, this);
// type check the body once
state.EnterScope();
state.BindVariable(ArgumentName, ArgumentType);
var returnType = Body.Typecheck(state);
if (returnType != ReturnType)
{
TypeError("Return type mismatch");
}
state.ExitScope();
var type = Recipient.Typecheck(state);
state.ExitScope();
return(type);
}
public abstract Type Typecheck(TypecheckingState state);
// public bool Value;
public override Type Typecheck(TypecheckingState state)
{
return(Type.BoolType);
}
// public Expression Expression1;
// public Expression Expression2;
public override Type Typecheck(TypecheckingState state)
{
Expression1.Typecheck(state);
return(Expression2.Typecheck(state));
}
public override Type Typecheck(TypecheckingState state)
{
throw new NotImplementedException();
}