/// <summary>
/// Converts the given abstract expression into a list of possible AST expressions.
/// Throws an exception if the translation was not possible because of unfinished symbols
/// </summary>
/// <param name="unit"></param>
/// <param name="scope"></param>
/// <param name="value"></param>
/// <param name="context"></param>
/// <returns></returns>
private IReadOnlyList <Expression> ConvertExpression(TranslationUnit unit, IScope scope, Grammar.Expression value, ExpressionContext context = null)
{
if (value is NumberLiteral num)
{
var literals = new List <Expression>();
// try hex first, then decimal
if (ulong.TryParse(num.Value.Substring(2), NumberStyles.HexNumber, SystemFormat, out ulong u))
{
if (u <= 0xFF)
{
literals.Add(new ByteLiteral((byte)u));
}
literals.Add(new UIntLiteral(u));
}
else if (ulong.TryParse(num.Value, NumberStyles.Integer, SystemFormat, out u))
{
if (u <= 0xFF)
{
literals.Add(new ByteLiteral((byte)u));
}
literals.Add(new UIntLiteral(u));
}
// try hex first, then decimal
if (long.TryParse(num.Value.Substring(2), NumberStyles.HexNumber, SystemFormat, out long i))
{
literals.Add(new IntLiteral(i));
}
else if (long.TryParse(num.Value, NumberStyles.Integer, SystemFormat, out i))
{
literals.Add(new IntLiteral(i));
}
// also try double separated
if (double.TryParse(num.Value, NumberStyles.Number, SystemFormat, out double dbl))
{
literals.Add(new RealLiteral(dbl));
}
return(literals.ToArray());
}
else if (value is Grammar.StringLiteral str)
{
// this could be translated into an ArrayLiteral,
// but this allows a certain degree of optimization
return(new[] { new StringLiteral(str.Text) });
}
else if (value is CharacterLiteral chr)
{
return(new[] { new CharLiteral(chr.Codepoint) });
}
else if (value is ArrayLiteral array)
{
var expr = new ArrayExpression();
expr.Items = new Expression[array.Values.Count];
for (int i = 0; i < expr.Items.Length; i++)
{
int idx = i;
var elem = ConvertExpression(unit, scope, array.Values[idx]);
if (elem == null)
{
Error.InvalidExpression(value);
return(null);
}
expr.Items[idx] = elem.Single();
}
if (expr.Items.Any(i => i is null))
{
throw Error.Critical("Not all array elements could be translated!");
}
var type = FindCommonType(expr.Items.Select(i => i.Type));
if (type == null)
{
throw Error.NoCommmonType();
}
expr.ItemType = type;
return(new[] { expr });
}
else if (value is Grammar.FunctionLiteral function)
{
var type = ConvertType(unit, scope, function.Type) as FunctionType;
if (type == null)
{
throw Error.UnresolvableType(function.Type);
}
var fun = new UserFunction(type);
var paramscope = new SimpleScope();
for (int i = 0; i < type.Parameters.Length; i++)
{
var param = type.Parameters[i];
paramscope.Add(new Symbol(param.Type, param.Name)
{
Kind = SymbolKind.Parameter,
ParameterIndex = i,
});
}
fun.Scope.Push(scope);
fun.Scope.Push(paramscope);
var ctx = new BlockContext
{
EnclosingType = type
};
// IMPORTANT:
// Use task system here as a function literal body is independent from its type
// and can be translated completly separated from the rest of the expression
unit.AddTask(() =>
{
var body = ConvertStatement(unit, fun.Scope, function.Body, ctx);
if (body == null)
{
return(Error.UntranslatableStatement(function.Body));
}
fun.Body = body;
return(Error.None);
});
unit.Module.Functions.Add(fun);
return(new[] { new FunctionLiteral(fun) });
}
else if (value is VariableReference vref)
{
var syms = scope.Where(s => s.Name.ID == vref.Variable).ToArray();
if (syms.Length == 0)
{
throw Error.SymbolNotFound(vref.Variable);
}
return(syms.Select(s => new SymbolReference(s)).ToArray());
}
else if (value is UnaryOperation unop)
{
var val = ConvertExpression(unit, scope, unop.Operand);
if (val == null)
{
throw Error.InvalidExpression(unop.Operand);
}
var results = new List <FunctionCall>();
foreach (var item in val)
{
var type = FunctionType.CreateUnaryOperator(Type.UnknownType, item.Type);
var sig = new Signature(type, unop.Operator);
if (scope.HasSymbol(sig) == false)
{
continue;
}
results.Add(new FunctionCall(new SymbolReference(scope[sig]), new[] { item }));
}
if (results.Count == 0)
{
throw Error.UnknownOperator(unop);
}
return(results);
}
else if (value is BinaryOperation binop)
{
var lhslist = ConvertExpression(unit, scope, binop.LeftHandSide);
var rhslist = ConvertExpression(unit, scope, binop.RightHandSide);
var results = new List <FunctionCall>();
foreach (var lhs in lhslist)
{
foreach (var rhs in rhslist)
{
var type = FunctionType.CreateBinaryOperator(
returnType: Type.UnknownType,
leftType: lhs.Type,
rightType: rhs.Type);
var sig = new Signature(type, binop.Operator);
if (scope.HasSymbol(sig) == false)
{
continue;
}
results.Add(new FunctionCall(new SymbolReference(scope[sig]), new[] { lhs, rhs }));
}
}
if (results.Count == 0)
{
Error.UnknownOperator(binop);
}
return(results);
}
else if (value is FunctionCallExpression fncall)
{
var results = new List <FunctionCall>();
var functions = ConvertExpression(unit, scope, fncall.Value);
foreach (var func in functions)
{
var type = func.Type as FunctionType;
if (type == null)
{
continue;
}
var call = new FunctionCall();
call.Functor = func;
var arglist = new Expression[type.Parameters.Length];
var paramset = new HashSet <Parameter>(type.Parameters);
foreach (var arg in fncall.PositionalArguments)
{
var param = paramset.SingleOrDefault(p => p.Position == arg.Position);
if (param == null)
{
continue;
}
arglist[param.Position] = SelectFitting(
ConvertExpression(unit, scope, arg.Value),
param.Type);
if (arglist[param.Position] == null)
{
continue;
}
paramset.Remove(param);
}
foreach (var arg in fncall.NamedArguments)
{
var param = paramset.SingleOrDefault(p => p.Name == arg.Name);
if (param == null)
{
continue;
}
arglist[param.Position] = ConvertExpression(unit, scope, arg.Value).Single();
if (arglist[param.Position] == null)
{
continue;
}
paramset.Remove(param);
}
if (paramset.Count > 0)
{
continue;
}
call.Arguments = arglist;
results.Add(call);
}
if (results.Count == 0)
{
throw Error.Critical($"Unknown function {fncall.Value} with fitting argument list.");
}
return(results);
}
else
{
throw new NotSupportedException($"The expression type '{value?.GetType()?.Name ?? "?"}' is not supported yet.");
}
}
private SimpleScope(SimpleScope other)
{
this.symbols = new Dictionary <Signature, Symbol>(other.symbols);
}
