public DelegateT Parse()
{
var method = new DynamicMethod(
"Evaluate",
typeof(long),
new Type[] { typeof(long), typeof(long), typeof(long) }
);
var generator = method.GetILGenerator();
PeekToken();
if (TestNoShift(Token.Type.VarDefStatement))
{
VarDefStatement defStt = token.GetData <VarDefStatement>();
defStt.Emit(generator);
int i = 0;
defStt.names.ForEach(name => vars[name] = new Variable(name, i++, true));
PeekToken(ProgramState.AfterDef);
}
foreach (var(name, obj) in globalVars)
{
if (!vars.ContainsKey(name))
{
vars[name] = obj;
}
}
IBaseStatement stt = null;
bool returns = false;
while (HasToken())
{
stt = token.GetData <IBaseStatement>();
returns |= stt.CheckReturn();
stt.Emit(generator);
CommitPeek();
if (lexer.Source.CommitAndCheckIsEnd())
{
break;
}
RePeekToken(ProgramState.AfterDef);
}
if (!returns)
{
throw new CompileException(
"end of function is reachable without any return statement"
);
}
if (!(stt is ReturnStatement))
{
new ReturnStatement(new Const(0)).Emit(generator); // load dummy to not get error
}
return((DelegateT)method.CreateDelegate(typeof(DelegateT)));
}
public bool CheckReturn()
{
if (precalc.HasValue)
{
// precalculated
if (precalc.Value)
{
return(ifBranch.CheckReturn());
}
else if (elseBranch != null)
{
return(elseBranch.CheckReturn());
}
else
{
return(false);
}
}
// general case
return(ifBranch.CheckReturn() && elseBranch != null && elseBranch.CheckReturn());
}