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public static Lalr1ParseTable ToLalr1ParseTable(this CfgDocument cfg)
{
	var start = cfg.GetAugmentedStartId(cfg.StartSymbol);
	var pda = _ToLrfa(cfg);
	var trnsCfg = _ToLRTransitionGrammar(cfg,pda);
	var closure = new List<FA<string, ICollection<LRItem>>>();
	var lalrclosure = new Lalr1ParseTable();

	var itemSets = new List<ICollection<LRItem>>();

	pda.FillClosure(closure);
	var i = 0;
	foreach (var p in closure)
	{
		itemSets.Add(p.AcceptSymbol);
		lalrclosure.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);
			lalrclosure[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)
			{
				lalrclosure[i].Add(
					"#EOS",
					(-1, null, null));
				break;
			}
		}
		++i;
	}
	// work on our reductions now
	var map = new Dictionary<CfgRule, ICollection<string>>(_TransitionMergeRuleComparer.Default);
	var follows = trnsCfg.FillFollows();
	var rtbl = new List<IDictionary<object, CfgRule>>();
	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);
	}
	foreach (var me in map)
	{
		var rule = me.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 me.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);
				if (0 > rid)
					System.Diagnostics.Debugger.Break(); // couldn't find our rule

				// this gets rid of duplicate entries which seem to crop up in the table
				// TODO: I think this is a shift reduce conflict if it debugger-breaks
				if (lalrclosure[lr.To].TryGetValue(iid, out tuple))
				{
					if (rid != tuple.RuleOrStateId)
						System.Diagnostics.Debugger.Break(); // possible shift-reduce conflice?
				}
				else
				{
					lalrclosure[lr.To].Add(_LrtSymbol.Parse(f).Id,
						(rid, newRule.Left, rr));
				}
			}
	}
	return lalrclosure;
}

honey the monster, codewitch wrote:

6 page pile of rubbish I spent 3 days implementing before I realized it was someone's homework assignment and not a whitepaper (they really should warn people)

CPallini wrote:

I've just put my empty beer can in the robot who will replace the PM