private static void ParseForEachLoop(Scope scope, LuaLexer code)
{
ParameterExpression varEnumerable = Expression.Variable(typeof(System.Collections.IEnumerable), "#enumerable");
ParameterExpression varEnumerator = Expression.Variable(typeof(System.Collections.IEnumerator), "#enumerator");
// foreach name in exp do block end;
code.Next(); // foreach
// fetch the loop variable
LoopScope loopScope = new LoopScope(scope);
Token tLoopVar;
Type typeLoopVar;
ParseIdentifierAndType(scope, code, out tLoopVar, out typeLoopVar);
ParameterExpression loopVar = loopScope.RegisterVariable(typeLoopVar, tLoopVar.Value);
// get the enumerable expression
FetchToken(LuaToken.KwIn, code);
Expression exprEnum = Lua.EnsureType(ParseExpression(scope, code, InvokeResult.None, scope.EmitExpressionDebug), typeof(object));
// parse the loop body
FetchToken(LuaToken.KwDo, code);
ParseBlock(loopScope, code);
FetchToken(LuaToken.KwEnd, code);
loopScope.InsertExpression(0, Expression.Assign(loopVar, ConvertExpression(scope.Runtime, tLoopVar, Expression.Property(varEnumerator, Lua.EnumeratorCurrentPropertyInfo), loopVar.Type)));
scope.AddExpression(
Expression.Block(new ParameterExpression[] { varEnumerable, varEnumerator, loopVar },
// local enumerable = exprEnum as IEnumerator
Expression.Assign(varEnumerable, Expression.TypeAs(exprEnum, typeof(System.Collections.IEnumerable))),
// if enumerable == nil then error
Expression.IfThen(Expression.Equal(varEnumerable, Expression.Constant(null, typeof(object))), Lua.ThrowExpression(Properties.Resources.rsExpressionNotEnumerable)),
// local enum = exprEnum.GetEnumerator()
Expression.Assign(varEnumerator, Expression.Call(varEnumerable, Lua.EnumerableGetEnumeratorMethodInfo)),
// while enum.MoveNext() do
Expression.Label(loopScope.ContinueLabel),
Expression.IfThenElse(Expression.Call(varEnumerator, Lua.EnumeratorMoveNextMethodInfo), Expression.Empty(), Expression.Goto(loopScope.BreakLabel)),
// loopVar = enum.Current
loopScope.ExpressionBlock,
// end;
Expression.Goto(loopScope.ContinueLabel),
Expression.Label(loopScope.BreakLabel)
));
}
private static void ParseForLoop(Scope scope, LuaLexer code)
{
// for name
FetchToken(LuaToken.KwFor, code);
Token tLoopVar;
Type typeLoopVar;
ParseIdentifierAndType(scope, code, out tLoopVar, out typeLoopVar);
if (code.Current.Typ == LuaToken.Assign)
{
// = exp, exp [, exp] do block end
FetchToken(LuaToken.Assign, code);
Expression loopStart = ParseExpression(scope, code, InvokeResult.Object, scope.EmitExpressionDebug);
FetchToken(LuaToken.Comma, code);
Expression loopEnd = ParseExpression(scope, code, InvokeResult.Object, scope.EmitExpressionDebug);
Expression loopStep;
if (code.Current.Typ == LuaToken.Comma)
{
code.Next();
loopStep = ParseExpression(scope, code, InvokeResult.Object, scope.EmitExpressionDebug);
}
else
loopStep = Expression.Constant(1, loopStart.Type);
LoopScope loopScope = new LoopScope(scope);
ParameterExpression loopVarParameter = loopScope.RegisterVariable(typeLoopVar == typeof(object) ? LuaEmit.LiftType(LuaEmit.LiftType(loopStart.Type, loopEnd.Type), loopStep.Type) : typeLoopVar, tLoopVar.Value);
FetchToken(LuaToken.KwDo, code);
ParseBlock(loopScope, code);
FetchToken(LuaToken.KwEnd, code);
scope.AddExpression(GenerateForLoop(loopScope, tLoopVar, loopVarParameter, loopStart, loopEnd, loopStep));
}
else
{
// {, name} in explist do block end
// fetch all loop variables
LoopScope loopScope = new LoopScope(scope);
List<ParameterExpression> loopVars = new List<ParameterExpression>();
loopVars.Add(loopScope.RegisterVariable(typeLoopVar, tLoopVar.Value));
while (code.Current.Typ == LuaToken.Comma)
{
code.Next();
ParseIdentifierAndType(scope, code, out tLoopVar, out typeLoopVar);
loopVars.Add(loopScope.RegisterVariable(typeLoopVar, tLoopVar.Value));
}
// get the loop expressions
FetchToken(LuaToken.KwIn, code);
Expression[] explist = ParseExpressionList(scope, code).ToArray();
// parse the loop body
FetchToken(LuaToken.KwDo, code);
ParseBlock(loopScope, code);
FetchToken(LuaToken.KwEnd, code);
scope.AddExpression(GenerateForLoop(loopScope, tLoopVar, loopVars, explist));
}
}