void CreateSeparator()
{
var alt = new AlternativeParser();
var p = Comment;
if (p != null)
alt.Items.Add(p);
p = Whitespace;
if (p != null)
alt.Items.Add(p);
if (alt.Items.Count == 0)
separator = null;
else
separator = -alt;
}
Parser CharacterSet(Match match)
{
var alt = new AlternativeParser();
var inverse = match.Text.StartsWith("[^", StringComparison.Ordinal);
var characters = new List<char>();
foreach (var child in match.Matches.Where(r => r.Name != null))
{
switch (child.Name)
{
case "character range":
var first = Character(child.Matches.First(r => r.Name == "character"));
var last = Character(child.Matches.Last(r => r.Name == "character"));
if (first != null && last != null)
alt.Add(new CharRangeTerminal(first.Value, last.Value) { Inverse = inverse });
break;
case "character":
var character = Character(child);
if (character != null)
characters.Add(character.Value);
break;
default:
throw new FormatException(string.Format("Invalid character set child for text '{0}'", child.Text));
}
}
if (characters.Count > 0)
{
alt.Add(new CharSetTerminal(characters.ToArray()) { Inverse = inverse });
}
if (alt.Items.Count > 1)
return alt;
if (alt.Items.Count > 0)
return alt.Items[0];
return new UnaryParser();
//throw new FormatException(string.Format("Character set has no characters '{0}'", match.Text));
}
public EbnfGrammar(EbnfStyle style)
: base("ebnf")
{
Style = style;
DefineCommonNonTerminals = true;
GenerateSpecialSequences();
// terminals
var comment = style.HasFlag(EbnfStyle.BracketComments) ? new GroupParser("(*", "*)") : new GroupParser("/*", "*/");
var ows = -(Terminals.WhiteSpace | comment);
var rws = +(Terminals.WhiteSpace | comment);
var hex_character = ("#x" & +Terminals.HexDigit);
var character = (("\\" & Terminals.AnyChar) | hex_character | Terminals.AnyChar.Except("]")).WithName("character");
var character_range = (character & "-" & character).WithName("character range");
var character_set = ("[" & ~(Parser)"^" & +(character_range | character) & "]").WithName("character set");
var terminal_string = new StringParser { QuoteCharacters = new [] { '\"', '\'', '’' }, Name = "terminal string" };
var special_sequence = ("?" & (+Terminals.AnyChar).Until("?").WithName("name") & "?").WithName("special sequence");
var meta_identifier_terminal = Terminals.Letter & -(Terminals.LetterOrDigit | '_');
var integer = new NumberParser().WithName("integer");
// nonterminals
var definition_list = new RepeatParser(0).WithName("definition list");
var single_definition = new RepeatParser(1).WithName("single definition");
var term = new SequenceParser().WithName("term");
var primary = new AlternativeParser().WithName("primary");
var exception = new UnaryParser("exception");
var factor = new SequenceParser().WithName("factor");
var meta_identifier = new RepeatParser(1).WithName("meta identifier");
var syntax_rule = new SequenceParser().WithName("syntax rule");
var rule_equals = new AlternativeParser().WithName("equals");
Parser meta_reference = meta_identifier;
Parser grouped_sequence = ("(" & ows & definition_list & ows & ")").WithName("grouped sequence");
if (style.HasFlag(EbnfStyle.SquareBracketAsOptional))
{
primary.Add(("[" & ows & definition_list & ows & "]").WithName("optional sequence"));
}
if (!style.HasFlag(EbnfStyle.CardinalityFlags))
{
var repeated_sequence = ("{" & ows & definition_list & ows & "}").WithName("repeated sequence");
primary.Add(repeated_sequence);
}
// rules
meta_identifier.Inner = meta_identifier_terminal;
meta_identifier.Separator = +(Terminals.SingleLineWhiteSpace);
if (!style.HasFlag(EbnfStyle.CommaSeparator))
{
// w3c identifiers must be a single word
meta_identifier.Maximum = 1;
meta_reference = meta_reference.NotFollowedBy(ows & rule_equals);
}
primary.Add(grouped_sequence, meta_reference, terminal_string, special_sequence);
if (style.HasFlag(EbnfStyle.CharacterSets) && !style.HasFlag(EbnfStyle.SquareBracketAsOptional))
{
// w3c supports character sets
primary.Add(hex_character.Named("hex character"));
primary.Add(character_set);
}
if (style.HasFlag(EbnfStyle.NumericCardinality))
factor.Add(~(integer & ows & "*" & ows));
factor.Add(primary);
if (style.HasFlag(EbnfStyle.CardinalityFlags))
{
// w3c defines cardinality at the end of a factor
var flags = style.HasFlag(EbnfStyle.SquareBracketAsOptional) ? "*+" : "?*+";
factor.Add(~(ows & Terminals.Set(flags).WithName("cardinality")));
}
term.Add(factor, ~(ows & "-" & ows & exception));
exception.Inner = term;
single_definition.Inner = term;
single_definition.Separator = style.HasFlag(EbnfStyle.CommaSeparator) ? (Parser)(ows & "," & ows) : ows;
definition_list.Inner = single_definition;
definition_list.Separator = ows & "|" & ows;
rule_equals.Add(style.HasFlag(EbnfStyle.DoubleColonEquals) ? "::=" : "=", ":=");
syntax_rule.Add(meta_identifier, ows, rule_equals, ows, definition_list);
if (style.HasFlag(EbnfStyle.SemicolonTerminator))
syntax_rule.Add(ows, ";"); // iso rules are terminated by a semicolon
var syntax_rules = +syntax_rule;
syntax_rules.Separator = style.HasFlag(EbnfStyle.SemicolonTerminator) ? ows : rws;
Inner = ows & syntax_rules & ows;
AttachEvents();
}
public BnfGrammar(bool enhanced = true)
: base("bnf")
{
if (enhanced)
{
foreach (var property in typeof(Terminals).GetProperties())
{
if (typeof(Parser).IsAssignableFrom(property.PropertyType))
{
var parser = property.GetValue(null, null) as Parser;
baseLookup[property.Name] = parser.Named(property.Name);
}
}
}
var lineEnd = sws & +(sws & Terminals.Eol);
literal = (
(sq & (+!sq).Named("value").Optional() & sq)
| (dq & (+!dq).Named("value").Optional() & dq)
).Named("parser");
RuleNameParser = "<" & Terminals.Set('>').Inverse().Repeat().Named("name") & ">";
RuleParser = new AlternativeParser(); // defined later
TermParser = literal | (ruleName = RuleNameParser.Named("parser"));
if (enhanced)
{
TermParser.Items.Add('(' & sws & RuleParser & sws & ')');
TermParser.Items.Add(repeatRule = ('{' & sws & RuleParser & sws & '}').Named("parser"));
TermParser.Items.Add(optionalRule = ('[' & sws & RuleParser & sws & ']').Named("parser"));
}
list = (TermParser.Named("term") & -(~((+Terminals.SingleLineWhiteSpace).Named("ws")) & TermParser.Named("term"))).Named("parser");
listRepeat = (list.Named("list") & ws & '|' & sws & ~(RuleParser.Named("expression"))).Named("parser");
RuleParser.Items.Add(listRepeat);
RuleParser.Items.Add(list);
rule = (~lineEnd & sws & RuleNameParser.Named("ruleName") & ws & ruleSeparator & sws & RuleParser & lineEnd).Named("parser");
Expresssions = new AlternativeParser();
Expresssions.Items.Add(rule);
this.Inner = ws & +Expresssions & ws;
AttachEvents();
}
protected AlternativeParser(AlternativeParser other, ParserCloneArgs chain)
: base(other, chain)
{
}
