public Expr OnParseTryCatch()
{
var tokenIt = this._parser.TokenIt;
var initiatorToken = tokenIt.NextToken;
var expr = new TryCatchExpr();
// <codeTryCatch>
// Try
tokenIt.Expect(Tokens.Try);
expr.Statements = new List<Expr>();
this.ParseBlock(expr);
tokenIt.AdvancePastNewLines();
// Catch
var catchToken = tokenIt.NextToken;
tokenIt.ExpectMany(Tokens.Catch, Tokens.LeftParenthesis);
expr.ErrorName = tokenIt.ExpectId();
tokenIt.Expect(Tokens.RightParenthesis);
expr.Catch = new BlockExpr();
this.ParseBlock(expr.Catch);
this._parser.SetupContext(expr.Catch, catchToken);
// </codeTryCatch>
this._parser.SetupContext(expr, initiatorToken);
return expr;
}
/// <summary>
/// Execute
/// </summary>
public object VisitTryCatch(TryCatchExpr expr)
{
var tryScopePopped = false;
var catchScopePopped = false;
try
{
this.Ctx.Memory.Push();
LangHelper.Evaluate(expr.Statements, expr, this);
this.Ctx.Memory.Pop();
tryScopePopped = true;
}
// Force the langlimit excpetion to propegate
// do not allow to flow through to the catch all "Exception ex".
catch (LangLimitException)
{
throw;
}
catch (LangFailException)
{
throw;
}
catch (Exception ex)
{
this.Ctx.Limits.CheckExceptions(expr);
// Pop the try scope.
if (!tryScopePopped) this.Ctx.Memory.Pop();
// Push the scope in the catch block
this.Ctx.Memory.Push();
var lException = LangTypeHelper.ConvertToLangClass(LError.FromException(ex));
this.Ctx.Memory.SetValue(expr.ErrorName, lException);
// Run statements in catch block.
if (expr.Catch != null && expr.Catch.Statements.Count > 0)
LangHelper.Evaluate(expr.Catch.Statements, expr.Catch, this);
// Pop the catch scope.
this.Ctx.Memory.Pop();
catchScopePopped = true;
}
finally
{
// Pop the catch scope in case there was an error.
if (!catchScopePopped) this.Ctx.Memory.Remove(expr.ErrorName);
}
return LObjects.Null;
}
/// <summary>
/// Visits the try statement tree.
/// </summary>
/// <param name="tryExpr"></param>
public object VisitTryCatch(TryCatchExpr expr)
{
_callBackOnNodeStart(expr);
foreach (var stmt in expr.Statements)
{
stmt.Visit(this);
}
foreach (var stmt in expr.Catch.Statements)
{
stmt.Visit(this);
}
return null;
}
