private void InferLambda(LambdaExpression le, TypeInferenceCache cache)
{
// lambda is the only one expression that can have its type set from outside
if (!cache.ContainsKey(le))
{
var lambdaType = Enumerable.Repeat(typeof(Variant), 1 + le.Args.Count()).ForgeFuncType();
cache.Add(le, new Lambda(le, lambdaType));
}
// detect overlapping variables
var closure = le.Parent == null ? null : le.Parent.GetClosure();
if (closure != null)
{
var overlapping = closure.Keys.Intersect(le.Args);
if (overlapping.IsNotEmpty())
{
throw new RedeclaredVariableException(Root, le, closure);
}
}
// detect overriding keywords
foreach (var arg in le.Args)
{
if (Integration.IsRegisteredJS(arg))
{
throw new VariableOverridesKeywordException(Root, le, arg);
}
}
InferTypes(le.Body, cache);
}
public Lambda(LambdaExpression expression, Type type)
{
Expression = expression;
Type = type;
}
public RedeclaredVariableException(RelinqScriptExpression root, LambdaExpression le, Closure closure)
: base(JSToCSharpExceptionType.RedeclaredVariable, root, le)
{
Closure = closure;
Name = le.Args.Intersect(closure.Keys).First();
}
public VariableOverridesKeywordException(RelinqScriptExpression root, LambdaExpression le, String name)
: base(JSToCSharpExceptionType.VariableOverridesKeyword, root, le)
{
Name = name;
}
private LinqExpression CompileLambda(LambdaExpression le, CompilationContext ctx)
{
var lambda = ctx.Types[le] as Lambda;
if (lambda == null)
{
throw new CSharpBuilderException(
JSToCSharpExceptionType.UnexpectedInferredAst, Ast, le, ctx);
}
var @params = le.Args.Select((arg, i) =>
LinqExpression.Parameter(lambda.Type.GetFunctionDesc().Args.ElementAt(i), arg)).
ToDictionary(param => param.Name);
foreach (var name in @params.Keys)
{
if (Integration.IsRegisteredJS(name))
{
throw new CSharpBuilderException(
JSToCSharpExceptionType.UnexpectedInferredAst, Ast, le, ctx);
}
else if (ctx.Closure.ContainsKey(name))
{
throw new CSharpBuilderException(
JSToCSharpExceptionType.UnexpectedInferredAst, Ast, le, ctx);
}
else
{
ctx.Closure.Add(name, @params[name]);
}
}
try
{
// todo. also yield cast to convert return types?
return LinqExpression.Lambda(Compile(le.Body, ctx), @params.Values.ToArray());
}
finally
{
ctx.Closure.RemoveRange(@params.Keys);
}
}
