private bool ParseStatement(TokenReader reader, out Statement result)
{
result = null;
Token tok = reader.Peek();
Token start = tok;
if (tok.Is(Keyword.SemiColon))
{
return true; // empty statement.
}
if (tok.Is(Keyword.If))
{
return this.ParseIfStatement(reader, out result);
}
if (tok.Is(Keyword.While))
{
return this.ParseWhileStatement(reader, out result);
}
if (tok.Is(Keyword.Delete))
{
return this.ParseDeleteStatement(reader, out result);
}
if (tok.Is(Keyword.Begin))
{
BlockStatement block = null;
bool success = this.ParseBlockStatement(reader, out block);
result = block;
return success;
}
ReferenceExpression lhs = null;
if (!this.ParseReferenceExpression(reader, out lhs))
{
return false;
}
tok = reader.Peek();
if (tok.Is(Keyword.Assign))
{
reader.Read();
Expression rhs = null;
if (!this.ParseExpression(reader, out rhs))
{
return false;
}
result = new AssignmentStatement(start, lhs, rhs);
return true;
}
else
{
result = new CallStatement(start, lhs);
return true;
}
}
private bool TryEmitAssignment(
AssignmentStatement assignmentStatement,
CompilerContext context,
Scope scope,
MethodImpl method)
{
string location = null;
TypeDefinition storageType = null;
TypeDefinition valueType = null;
if (!this.TryEmitExpression(assignmentStatement.Value, context, scope, method, out valueType))
{
return false;
}
this.PushResult(method, valueType);
MethodInfo calleeMethod = null;
if (!this.TryEmitReference(assignmentStatement.Storage, context, scope, method, out location, out storageType, out calleeMethod))
{
return false;
}
if (!this.ValidateCanCast(assignmentStatement, storageType, valueType))
{
return false;
}
if (valueType.Size == 8 && !valueType.IsClass)
{
method.Statements.Add(new AsmStatement { Instruction = "pop eax" });
method.Statements.Add(new AsmStatement { Instruction = "pop edx" });
method.Statements.Add(new AsmStatement { Instruction = string.Format("lea ecx,{0}", location) });
method.Statements.Add(new AsmStatement { Instruction = "mov [ecx],eax" });
method.Statements.Add(new AsmStatement { Instruction = "add ecx,4" });
method.Statements.Add(new AsmStatement { Instruction = "mov [ecx],edx" });
}
else if (valueType.Size <= 4 && !valueType.IsClass)
{
method.Statements.Add(new AsmStatement { Instruction = "pop eax" });
switch (storageType.Size)
{
case 1:
{
method.Statements.Add(new AsmStatement { Instruction = string.Format("mov byte ptr {0},al", location) });
} break;
case 2:
{
method.Statements.Add(new AsmStatement { Instruction = string.Format("mov word ptr {0},ax", location) });
} break;
default:
{
method.Statements.Add(new AsmStatement { Instruction = string.Format("mov {0},eax", location) });
} break;
}
}
else
{
method.Statements.Add(new AsmStatement { Instruction = "mov esi,esp" });
method.Statements.Add(new AsmStatement { Instruction = string.Format("lea edi,{0}", location) });
method.Statements.Add(new AsmStatement { Instruction = string.Format("mov ecx,{0}", valueType.Size) });
method.Statements.Add(new AsmStatement { Instruction = "cld" });
method.Statements.Add(new AsmStatement { Instruction = "rep movsb" });
method.Statements.Add(new AsmStatement { Instruction = string.Format("add esp,{0}", valueType.Size) });
}
return true;
}