public Production(ConfigSection section, SyntacticConfigurationFile config)
{
this.Key = new Symbol(config.GetRule(SyntacticConfigurationFile.RULE_PRODUCTION_PREFIX_KEY) + section.Header.First(), config);
this.Rules = new List <Rule>();
foreach (var entry in section.Header)
{
if (entry.StartsWith(SyntacticConfigurationFile.HEADER_EPSILON_PREFIX))
{
string value = entry.Remove(0, SyntacticConfigurationFile.HEADER_EPSILON_PREFIX.Length);
if (bool.TryParse(value, out bool canBeEpsilon))
{
this.CanBeEpsilon = canBeEpsilon;
}
else
{
Log.WriteLineWarning($"Unable to determine if {this.Key.ID} production can be epsilon or not from: '{value}'.");
}
}
}
foreach (var line in section.Body.Where(line => !string.IsNullOrWhiteSpace(line)))
{
var rule = new Rule(this.Key, line, config);
this.Rules.Add(rule);
}
}
private void ProcessSection(ConfigSection section, SyntacticConfigurationFile config)
{
Debug.Assert(section.Header.Any(entry => !string.IsNullOrEmpty(entry)), $"Cannot have empty {SyntacticConfigurationFile.SECTION_TAG_PRODUCTION} header at {section.GetLocation()}");
string key = section.Header.First();
var production = new Production(section, config);
this._productions.Add(key, production);
}
private void AddExtraStartProduction(SyntacticConfigurationFile config)
{
// Insert the S' -> S production to guarentee one /single/ rule in the start production.
string start = config.GetRule(SyntacticConfigurationFile.RULE_START_KEY).ToString();
string realStart = start + START_PRIME;
char prefix = config.GetRule(SyntacticConfigurationFile.RULE_PRODUCTION_PREFIX_KEY);
var section = new ConfigSection(
$"#{SyntacticConfigurationFile.SECTION_TAG_PRODUCTION} {realStart}",
new string[] { $"{prefix}{start}" },
$"({nameof(ProductionTable)}.cs)",
-1
);
ProcessSection(section, config);
}
public ProductionTable(SyntacticConfigurationFile config)
{
this._productions = new Dictionary <string, Production>();
this._first = new Dictionary <string, HashSet <Symbol> >();
this.AddExtraStartProduction(config);
foreach (var section in config.GetSections(SyntacticConfigurationFile.SECTION_TAG_PRODUCTION))
{
ProcessSection(section, config);
}
this.TransformEpsilonTransitions(config);
this.ComputeFirst();
}
public Rule(Symbol key, string line, SyntacticConfigurationFile config)
{
this.Key = key;
this.Symbols = new List <Symbol>();
var sb = new StringBuilder();
var symbols = line.Split(' ');
foreach (var symbolData in symbols)
{
var symbol = new Symbol(symbolData, config);
this.Symbols.Add(symbol);
sb.Append(symbol.ID);
}
this.TextRepresentation = sb.ToString();
}
private void TransformEpsilonTransitions(SyntacticConfigurationFile config)
{
var productionsWithEpsilonTransitions = new HashSet <string>(this._productions.Where(entry => entry.Value.CanBeEpsilon).Select(entry => entry.Key));
foreach (var entry in this._productions)
{
var allNewRules = new List <Rule?>();
foreach (var rule in entry.Value.Rules)
{
foreach (var newRule in Permute(rule, 0, productionsWithEpsilonTransitions, false))
{
allNewRules.Add(newRule);
}
}
foreach (var newRule in allNewRules.Where(newRule => newRule != null))
{
if (!entry.Value.Rules.Contains(newRule))
{
entry.Value.Rules.Add(newRule);
}
}
}
}
