private Expression Convert(LinqExp.MethodCallExpression linqCall)
{
return(Expression.Call(
ConvertExp(linqCall.Object),
linqCall.Method,
Convert(linqCall.Arguments)));
}
internal Expression Reduce()
{
// Visit body
Expression body = Visit(_generator.Body);
Debug.Assert(_returnLabels.Count == 1);
// Add the switch statement to the body
int count = _yields.Count;
var cases = new SwitchCase[count + 1];
for (int i = 0; i < count; i++)
{
cases[i] = Expression.SwitchCase(Expression.Goto(_yields[i].Label), AstUtils.Constant(_yields[i].State));
}
cases[count] = Expression.SwitchCase(Expression.Goto(_returnLabels.Peek()), AstUtils.Constant(Finished));
Type generatorNextOfT = typeof(GeneratorNext <>).MakeGenericType(_generator.Target.Type);
// Create the lambda for the GeneratorNext<T>, hoisting variables
// into a scope outside the lambda
var allVars = new List <ParameterExpression>(_vars);
allVars.AddRange(_temps);
// Collect temps that don't have to be closed over
var innerTemps = new ReadOnlyCollectionBuilder <ParameterExpression>(1 + (_labelTemps != null ? _labelTemps.Count : 0));
innerTemps.Add(_gotoRouter);
if (_labelTemps != null)
{
foreach (LabelInfo info in _labelTemps.Values)
{
innerTemps.Add(info.Temp);
}
}
body = Expression.Block(
allVars,
Expression.Lambda(
generatorNextOfT,
Expression.Block(
innerTemps,
Expression.Switch(Expression.Assign(_gotoRouter, _state), cases),
body,
Expression.Assign(_state, AstUtils.Constant(Finished)),
Expression.Label(_returnLabels.Peek())
),
_generator.Name,
new ParameterExpression[] { _state, _current }
)
);
// Enumerable factory takes Func<GeneratorNext<T>> instead of GeneratorNext<T>
if (_generator.IsEnumerable)
{
body = Expression.Lambda(body);
}
// We can't create a ConstantExpression of _debugCookies array here because we walk the tree
// after constants have already been rewritten. Instead we create a NewArrayExpression node
// which initializes the array with contents from _debugCookies
Expression debugCookiesArray = null;
if (_debugCookies != null)
{
Expression[] debugCookies = new Expression[_debugCookies.Count];
for (int i = 0; i < _debugCookies.Count; i++)
{
debugCookies[i] = AstUtils.Constant(_debugCookies[i]);
}
debugCookiesArray = Expression.NewArrayInit(
typeof(int),
debugCookies);
}
// Generate a call to ScriptingRuntimeHelpers.MakeGenerator<T>(args)
return(Expression.Call(
typeof(ScriptingRuntimeHelpers),
"MakeGenerator",
new[] { _generator.Target.Type },
(debugCookiesArray != null)
? new[] { body, debugCookiesArray }
: new[] { body }
));
}
