Pred NodeToPredCore(LNode expr, Context ctx = Context.Rule)
{
if (expr.IsCall)
{
bool slash = false, not;
if (expr.Calls(S.Tuple))
{
// sequence: (a, b, c)
if (expr.Calls(S.Tuple, 1))
{
return(NodeToPred(expr.Args[0], ctx));
}
return(ArgsToSeq(expr, ctx));
}
else if (expr.Calls(S.Braces))
{
// Just code: use an empty sequence
var seq = new Seq(expr);
seq.PostAction = RemoveBraces(expr);
return(seq);
}
else if (expr.Calls(S.OrBits, 2) || (slash = expr.Calls(S.Div, 2)))
{
// alternatives: a | b, a || b, a / b
LNode lhs = expr.Args[0], rhs = expr.Args[1];
BranchMode lhsMode, rhsMode;
Pred left = BranchToPred(lhs, out lhsMode, ctx);
Pred right = BranchToPred(rhs, out rhsMode, ctx);
return(Pred.Or(left, right, slash, expr, lhsMode, rhsMode, _sink));
}
else if (expr.Calls(_Star, 1) || expr.Calls(_Plus, 1) || expr.Calls(_Opt, 1))
{
// loop (a+, a*) or optional (a?)
return(TranslateLoopExpr(expr, ctx));
}
else if (expr.Calls(_Gate, 1) || expr.Calls(_EqGate, 1))
{
// => foo (LES-based parser artifact)
return(new Gate(expr, new Seq(F._Missing),
NodeToPred(expr.Args[0], Context.GateRight))
{
IsEquivalency = expr.Calls(_EqGate)
});
}
else if (expr.Calls(_Gate, 2) || expr.Calls(_EqGate, 2))
{
if (ctx == Context.GateLeft)
{
_sink.Write(Severity.Error, expr, "Cannot use a gate in the left-hand side of another gate");
}
return(new Gate(expr, NodeToPred(expr.Args[0], Context.GateLeft),
NodeToPred(expr.Args[1], Context.GateRight))
{
IsEquivalency = expr.Calls(_EqGate)
});
}
else if ((not = expr.Calls(_AndNot, 1)) || expr.Calls(_And, 1))
{
expr = expr.Args[0];
var subpred = AutoNodeToPred(expr, Context.And);
LNode subexpr = subpred as LNode, subexpr0 = subexpr;
bool local = false;
if (subexpr != null)
{
if ((subexpr = subexpr.WithoutAttrNamed(_Local)) != subexpr0)
{
local = true;
}
// we should default to [Local] eventually, so recognize [Hoist] too
subexpr = subexpr.WithoutAttrNamed(_Hoist);
}
return(new AndPred(expr, subexpr ?? subpred, not, local));
}
else if (expr.Calls(S.NotBits, 1))
{
var subpred = NodeToPred(expr.Args[0], ctx);
if (subpred is TerminalPred)
{
var term = (TerminalPred)subpred;
term.Set = term.Set.Inverted().WithoutEOF();
return(term);
}
else
{
_sink.Write(Severity.Error, expr,
"The set-inversion operator ~ can only be applied to a single terminal, not a '{0}'", subpred.GetType().Name);
return(subpred);
}
}
else if (expr.Calls(_Any, 2) && expr.Args[0].IsId)
{
return(Translate_any_in_Expr(expr, ctx));
}
else if ((expr.Name.Name.EndsWith(":") || expr.Name.Name.EndsWith("=")) && expr.ArgCount == 2)
{
return(TranslateLabeledExpr(expr, ctx));
}
}
// expr is an Id, literal, or non-special call
Rule rule = TryGetRule(expr);
if (rule != null)
{
//int ruleArgc = rule.Basis.Args[2].ArgCount;
//if (expr.ArgCount > ruleArgc) // don't complain about too few args, in case there are default args (I'm too lazy to check)
// _sink.Write(MessageSink.Error, expr, "Rule '{0}' takes {1} arguments ({2} given)", rule.Name, ruleArgc, expr.ArgCount);
return(new RuleRef(expr, rule)
{
Params = expr.Args
});
}
string errorMsg = null;
Pred terminal = _helper.CodeToTerminalPred(expr, ref errorMsg);
if (terminal == null)
{
errorMsg = errorMsg ?? "LLLPG: unrecognized expression";
terminal = new TerminalPred(expr, _helper.EmptySet);
_sink.Write(Severity.Error, expr, errorMsg);
}
else if (errorMsg != null)
{
_sink.Write(Severity.Warning, expr, errorMsg);
}
return(terminal);
}
Pred NodeToPredCore(LNode expr, Context ctx = Context.Rule)
{
if (expr.IsCall)
{
bool slash = false, not;
var name = expr.Name;
if (name == S.Tuple)
{
// sequence: (a, b, c)
if (expr.Calls(S.Tuple, 1))
{
return(NodeToPred(expr.Args[0], ctx));
}
return(TranslateToSeq(expr, ctx));
}
else if (name == S.Braces)
{
// User action {block}
if (ctx == Context.And || ctx == Context.GateLeft)
{
_sink.Error(expr, ctx == Context.And ?
"Cannot use an action block inside an '&' or '&!' predicate; these predicates are for prediction only." :
"Cannot use an action block on the left side of a '=>' gate; the left side is for prediction only.");
}
return(new ActionPred(expr, expr.Args));
}
else if (expr.Calls(S.OrBits, 2) || (slash = expr.Calls(S.Div, 2)))
{
// alternatives: a | b, a || b, a / b
LNode lhs = expr.Args[0], rhs = expr.Args[1];
BranchMode lhsMode, rhsMode;
Pred left = BranchToPred(lhs, out lhsMode, ctx);
Pred right = BranchToPred(rhs, out rhsMode, ctx);
return(Pred.Or(left, right, slash, expr, lhsMode, rhsMode, _sink));
}
else if (expr.Calls(_Star, 1) || expr.Calls(_Plus, 1) || expr.Calls(_Opt, 1))
{
// loop (a+, a*) or optional (a?)
return(TranslateLoopExpr(expr, ctx));
}
else if (expr.Calls(_Gate, 1) || expr.Calls(_EqGate, 1))
{
// => foo (LES-based parser artifact)
return(new Gate(expr, new Seq(F.Missing),
NodeToPred(expr.Args[0], Context.GateRight))
{
IsEquivalency = expr.Calls(_EqGate)
});
}
else if (expr.Calls(_Gate, 2) || expr.Calls(_EqGate, 2))
{
if (ctx == Context.GateLeft)
{
_sink.Error(expr, "Cannot use a gate in the left-hand side of another gate");
}
return(new Gate(expr, NodeToPred(expr.Args[0], Context.GateLeft),
NodeToPred(expr.Args[1], Context.GateRight))
{
IsEquivalency = expr.Calls(_EqGate)
});
}
else if ((not = expr.Calls(_AndNot, 1)) || expr.Calls(_And, 1))
{
return(TranslateAndPred(expr, not));
}
else if (expr.Calls(S.NotBits, 1))
{
var subpred = NodeToPred(expr.Args[0], ctx);
if (subpred is TerminalPred)
{
var term = (TerminalPred)subpred;
term.Set = term.Set.Inverted().WithoutEOF();
return(term);
}
else
{
_sink.Error(expr,
"The set-inversion operator ~ can only be applied to a single terminal, not a '{0}'", subpred.GetType().Name);
return(subpred);
}
}
else if ((name.Name.EndsWith(":") || name.Name.EndsWith("=")) && expr.ArgCount == 2)
{
return(TranslateLabeledExpr(expr, ctx));
}
else if (expr.Calls(_Any, 2) && expr.Args[0].IsId)
{
return(Translate_any_in_Expr(expr, ctx));
}
}
// expr is an Id, literal, or non-special call
Rule rule = TryGetRule(expr);
if (rule != null)
{
LNode _, args;
if (EcsValidators.MethodDefinitionKind(rule.Basis, out _, out _, out args, out _, false) == S.Fn)
{
if (expr.ArgCount > args.ArgCount) // don't complain about too few args, in case there are default args (I'm too lazy to check)
{
_sink.Error(expr, "Rule '{0}' takes {1} arguments ({2} given)", rule.Name, args.ArgCount, expr.ArgCount);
}
}
return(new RuleRef(expr, rule)
{
Params = expr.Args
});
}
string errorMsg = null;
Pred terminal = _helper.CodeToTerminalPred(expr, ref errorMsg);
if (terminal == null)
{
errorMsg = errorMsg ?? "LLLPG: unrecognized expression";
terminal = new TerminalPred(expr, _helper.EmptySet);
_sink.Error(expr, errorMsg);
}
else if (errorMsg != null)
{
_sink.Warning(expr, errorMsg);
}
return(terminal);
}