public AltRule(SymbolPosition pos, string markWith, IEnumerable <RhsGroup> groups, CodeMix gen)
{
this.Position = pos;
this.MarkWith = markWith;
// [@PARSER_USER_ACTION]
// here we swap the notion of user action
// if in grammar user didn't pass ANY code -- it means identity function
// if the grammar user pass empty code -- it means passing null value, so as shorcut set null as entire user action
if (gen == null) // if there was no code at all, we infer the end object
{
CodeMix mix = null;
if (inferEndObject(groups, ref mix))
{
this.Code = mix;
}
else
{
throw ParseControlException.NewAndRun("Couldn't infer which object to pass at " + pos.XYString());
}
}
// if there was an empty code, such code does not produce anything (i.e. null)
// thus we set entire action as null -- it is a shortcut
else if (gen.IsEmpty)
{
this.Code = null;
}
else
{
this.Code = gen;
}
SetGroups(groups);
}
private static bool inferEndObject(IEnumerable <RhsGroup> groups, ref CodeMix code)
{
IEnumerable <RhsSymbol> symbols = groups.Select(it => it.GetSymbols()).Flatten();
if (symbols.Any(it => it.IsError))
{
return(true);
}
if (symbols.Count() != 1)
{
symbols = symbols.Where(it => it.ObjName != null);
}
if (symbols.Count() != 1)
{
return(false);
}
RhsSymbol symbol = symbols.Single();
// underscore is not magic -- it is a nice shortcut in grammar file, but awful when reading the output code
// thus we change it to something more readable, and since it is automatic, we can do the change (because why not)
// this replacement is rather useful only for NLT developer(s)
if (symbol.ObjName == null || symbol.ObjName == "_")
{
symbol.ResetUserObjName();
code = new CodeMix(CodeMix.ObjectInferComment).AddBody(new CodeBody().AddPlaceholder(symbol.SymbolName));
}
else
{
code = new CodeMix(CodeMix.ObjectInferComment).AddBody(new CodeBody().AddIdentifier(symbol.ObjName));
}
return(true);
}
internal static AltRule CreateInternally(SymbolPosition pos, IEnumerable <RhsGroup> groups, CodeMix code)
{
return(new AltRule(pos, null, groups, code));
}
