public static CfgLalr1ParseTable ToLalr1ParseTable(this CfgDocument cfg, IProgress <CfgLalr1Progress> progress = null)
{
CfgLalr1ParseTable result = null;
var msgs = TryToLalr1ParseTable(cfg, progress, out result);
CfgException.ThrowIfErrors(msgs);
return(result);
}
public Lalr1DebugParser(CfgDocument cfg, IEnumerable <Token> tokenizer, CfgLalr1ParseTable parseTable = null)
{
_cfg = cfg;
_PopulateAttrs();
_stack = new Stack <int>();
_tokenEnum = tokenizer.GetEnumerator();
_parseTable = parseTable ?? cfg.ToLalr1ParseTable();
_nodeType = LRNodeType.Initial;
}
public static IList <CfgMessage> TryToLalr1ParseTable(this CfgDocument cfg, IProgress <CfgLalr1Progress> progress, out CfgLalr1ParseTable parseTable)
{
var result = new List <CfgMessage>();
var start = cfg.GetAugmentedStartId(cfg.StartSymbol);
var lrfa = _ToLrfa(cfg, progress);
var trnsCfg = _ToLRTransitionGrammar(cfg, lrfa, progress);
trnsCfg.RebuildCache();
var closure = new List <Lrfa>();
parseTable = new CfgLalr1ParseTable();
var itemSets = new List <ICollection <LRItem> >();
lrfa.FillClosure(closure);
var i = 0;
foreach (var p in closure)
{
itemSets.Add(p.AcceptSymbol);
parseTable.Add(new Dictionary <string, (int RuleOrStateId, string Left, string[] Right)>());
++i;
}
i = 0;
foreach (var p in closure)
{
foreach (var trn in p.Transitions)
{
var idx = closure.IndexOf(trn.Value);
parseTable[i].Add(
trn.Key,
(idx, null, null)
);
}
foreach (var item in p.AcceptSymbol)
{
if (Equals(item.Rule.Left, start) && item.RightIndex == item.Rule.Right.Count)
{
parseTable[i].Add(
"#EOS",
(-1, null, null));
break;
}
}
++i;
}
var follows = trnsCfg.FillFollows();
// work on our reductions now
var map = new Dictionary <CfgRule, ICollection <string> >(_TransitionMergeRuleComparer.Default);
foreach (var rule in trnsCfg.Rules)
{
ICollection <string> f;
if (!map.TryGetValue(rule, out f))
{
map.Add(rule, follows[rule.Left]);
}
else
{
foreach (var o in follows[rule.Left])
{
if (!f.Contains(o))
{
f.Add(o);
}
}
}
}
var j = 0;
foreach (var mapEntry in map)
{
if (null != progress)
{
progress.Report(new CfgLalr1Progress(CfgLalr1Status.ComputingReductions, j));
}
var rule = mapEntry.Key;
var lr = _LrtSymbol.Parse(rule.Right[rule.Right.Count - 1]);
var left = _LrtSymbol.Parse(rule.Left).Id;
var right = new List <string>();
foreach (var s in rule.Right)
{
right.Add(_LrtSymbol.Parse(s).Id);
}
var newRule = new CfgRule(left, right);
if (!Equals(left, start))
{
foreach (var f in mapEntry.Value)
{
// build the rule data
var rr = new string[newRule.Right.Count];
for (var ri = 0; ri < rr.Length; ri++)
{
rr[ri] = newRule.Right[ri];
}
var iid = _LrtSymbol.Parse(f).Id;
(int RuleOrStateId, string Left, string[] Right)tuple;
var rid = cfg.Rules.IndexOf(newRule);
var newTuple = (RuleOrStateId : rid, Left : newRule.Left, Right : rr);
// this gets rid of duplicate entries which crop up in the table
if (!parseTable[lr.To].TryGetValue(iid, out tuple))
{
parseTable[lr.To].Add(_LrtSymbol.Parse(f).Id,
newTuple);
}
else
{
// TODO: Verify this - may need the dragon book
if (null == tuple.Right)
{
var nr = cfg.Rules[rid];
var msg = new CfgMessage(CfgErrorLevel.Warning, -1, string.Format("Shift-Reduce conflict on rule {0}, token {1}", nr, iid), nr.Line, nr.Column, nr.Position);
if (!result.Contains(msg))
{
result.Add(msg);
}
}
else
{
if (rid != newTuple.RuleOrStateId)
{
var nr = cfg.Rules[rid];
var msg = new CfgMessage(CfgErrorLevel.Error, -1, string.Format("Reduce-Reduce conflict on rule {0}, token {1}", nr, iid), nr.Line, nr.Column, nr.Position);
if (!result.Contains(msg))
{
result.Add(msg);
}
}
}
}
}
}
++j;
}
return(result);
}
public static IList <CfgMessage> TryToLalr1ParseTable(this CfgDocument cfg, out CfgLalr1ParseTable parseTable) => TryToLalr1ParseTable(cfg, null, out parseTable);
