internal ParseResult Parse(ParseContext parentContext)
{
var ctx = new ParseContext(parentContext, this);
if (!parentContext.IsUnique(ctx))
{
return(ctx.Error("Infinite parsing loop detected."));
}
ParseResult failed = null;
SymbolExpectedError tailError = null;
var children = OnParse(ctx)
.TakeWhile(x => (failed = failed ?? (x.Success ? null : x)) == null &&
(tailError = x.TailError ?? tailError) == tailError)
.SelectMany(x => x.FlattenHierarchy ? x : Single(x))
.ToArray();
if (failed != null)
{
tailError = ctx.Expected(tailError, failed.Error as SymbolExpectedError);
}
return((failed != null && failed.Fatal)
? failed.Error
: SubstituteResult(new ParseResult(ctx, failed != null
? ctx.Expected(failed.Error as SymbolExpectedError, tailError)
: tailError, children)));
}
internal ParseResult(ParseContext ctx, SymbolExpectedError tailError, params ParseResult[] children)
{
Parser = ctx.Parser;
TailError = tailError;
Index = ctx.InitialOffset;
Length = ctx.Offset - ctx.InitialOffset;
_children = children;
Input = ctx.Input;
}
internal ParseResult(ParseContext ctx, SymbolExpectedError tailError, params ParseResult[] children)
{
Parser = ctx.Parser;
TailError = tailError;
Index = ctx.InitialOffset;
Length = ctx.Offset - ctx.InitialOffset;
_trim = ctx.Parent != null && ctx.Parent.WhitespacePolicy == WhitespacePolicy.Ignore;
_children = children;
Input = ctx.Input;
}
protected override IEnumerable <ParseResult> OnParse(ParseContext ctx)
{
SymbolExpectedError tailError = null;
// ReSharper disable once ConvertClosureToMethodGroup
foreach (var result in Parsers.Select(x => ctx.Parse(x)))
{
if (result.Success || tailError == null)
{
if (tailError != null)
{
result.TailError = ctx.Expected(result.TailError, tailError);
}
yield return(result);
tailError = result.TailError;
}
else
{
var error = result.Error as SymbolExpectedError;
if (error != null)
{
yield return(ctx.Expected(tailError, error));
}
else
{
yield return(result);
}
}
if (!result.Success)
{
yield break;
}
}
}