protected RepeatParser(RepeatParser other, ParserCloneArgs args)
: base(other, args)
{
Minimum = other.Minimum;
Maximum = other.Maximum;
Until = args.Clone(other.Until);
SkipUntil = other.SkipUntil;
CaptureUntil = other.CaptureUntil;
Separator = args.Clone(other.Separator);
}
Parser Primary(Match match, bool isTerminal)
{
var child = match.Matches.FirstOrDefault(r => r.Name != null);
if (child == null)
throw new FormatException(string.Format("Primary must have a child. Text: '{0}'", match.Text));
Parser parser;
switch (child.Name)
{
case "grouped sequence":
return new UnaryParser(DefinitionList(child["definition list"], isTerminal));
case "optional sequence":
return new OptionalParser(DefinitionList(child["definition list"], isTerminal));
case "repeated sequence":
var repeat = new RepeatParser(DefinitionList(child["definition list"], isTerminal), 0);
if (!isTerminal)
repeat.Separator = separator;
return repeat;
case "meta identifier":
if (!parserLookup.TryGetValue(child.Text, out parser))
{
parser = parserLookup[child.Text] = Terminals.LetterOrDigit.Repeat().Named(child.Text);
}
return parser;
case "terminal string":
return new LiteralTerminal(child.StringValue);
case "hex character":
return new SingleCharTerminal((char)int.Parse(child.Text.Substring(2), NumberStyles.HexNumber));
case "character set":
return CharacterSet(child);
case "special sequence":
var name = child["name"].Text.Trim();
if (specialLookup.TryGetValue(name, out parser))
return parser;
else
return null;
default:
throw new FormatException(string.Format("Could not parse child with name '{0}'", child.Name));
}
}
Parser Factor(Match match, bool isTerminal)
{
var primary = Primary(match["primary"], isTerminal);
var cardinality = match["cardinality"];
if (cardinality)
{
switch (cardinality.Text)
{
case "?":
primary = new OptionalParser(primary);
break;
case "*":
primary = new RepeatParser(primary, 0);
break;
case "+":
primary = new RepeatParser(primary, 1);
break;
default:
throw new FormatException(string.Format("Cardinality '{0}' is unknown", cardinality.Text));
break;
}
}
var integer = match["integer"];
if (integer)
return new RepeatParser(primary, Int32.Parse(integer.Text));
else
return primary;
}
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();
}
