private void AddActionEntry(Item item, Func <ActionParsingTableEntry, bool> action, string actionDescription, ItemSet set, TerminalExpressionDefinition expressionDefinition)
{
ParsingTableSegment segment = GetOrCreateSegment(set);
ActionParsingTableEntry existingEntry = (ActionParsingTableEntry)segment.Entries.FirstOrDefault(x =>
x is ActionParsingTableEntry apte &&
apte.ActionDescription == actionDescription &&
apte.ExpressionDefinition.IsEqualTo(expressionDefinition));
if (existingEntry == null)
{
segment.Entries.Add(new ActionParsingTableEntry
{
ItemSet = set,
ExpressionDefinition = expressionDefinition,
Items = new List <Item> {
item
},
ActionDescription = actionDescription,
Action = action
});
}
else
{
existingEntry.Items.Add(item);
}
}
public ParsingTable(List <ItemSet> C,
List <ExpressionDefinition> symbols,
Func <ActionParsingTableEntry, bool> shift,
Func <ActionParsingTableEntry, bool> accept,
Func <ActionParsingTableEntry, bool> reduce)
{
Dictionary <string, ExpressionSet> follows = new Dictionary <string, ExpressionSet>();
// Actions
foreach (ItemSet set in C)
{
foreach (Item item in set)
{
if (item.ExpressionAfterDot != null &&
item.ExpressionAfterDot is TerminalExpressionDefinition ted)
{
AddActionEntry(item, shift, "s", set, item.ExpressionAfterDot as TerminalExpressionDefinition);
}
else if (item.SubProduction.Production.Identifier == ParserConstants.Initial)
{
TerminalExpressionDefinition expressionDefinition = item.ExpressionAfterDot as TerminalExpressionDefinition;
expressionDefinition = expressionDefinition ?? new TerminalExpressionDefinition()
{
TokenType = TokenType.EndMarker
};
AddActionEntry(item, accept, "a", set, expressionDefinition);
}
else if (item.IsDotIndexAtEnd())
{
string identifier = item.SubProduction.Production.Identifier;
ExpressionSet follow;
if (!follows.TryGetValue(identifier, out follow))
{
follow = new NonTerminalExpressionDefinition()
{
Identifier = identifier
}.Follow();
follows.Add(identifier, follow);
}
foreach (TerminalExpressionDefinition ted1 in follow)
{
AddActionEntry(item, reduce, "r", set, ted1);
}
}
}
}
// Goto's
foreach (ItemSet set in C)
{
foreach (NonTerminalExpressionDefinition symbol in symbols.Where(x => x is NonTerminalExpressionDefinition))
{
if (set.Transitions.Any(x => x.Key.IsEqualTo(symbol)))
{
GetOrCreateSegment(set).Entries.Add(new GotoParsingTableEntry
{
ExpressionDefinition = symbol,
ItemSet = set,
Destination = set.Transitions[symbol]
});
}
}
}
}