/// <summary>
/// Parse a literal node as described in X3J20 "3.4.6 Literals".
/// </summary>
/// <remarks>
/// If the given token is not a legal token for a literal node,
/// it is simply returned in the residueToken output parameter,
/// and the function returns null.
/// </remarks>
/// <param name="parent">Parent node that defines the literal node.</param>
/// <param name="token">First token of the literal node.</param>
/// <returns>A literal node, or null in case of non-literal token.</returns>
protected virtual LiteralNode ParseLiteral(ILiteralNodeParent parent, Token token)
{
// PARSE: <literal> ::= <number literal> | <string literal> | <character literal> |
// <symbol literal> | <selector literal> | <array literal>
// <string literal> ::= quotedString
if (token is StringToken) // 'example'
{
return(new StringLiteralNode(parent, (StringToken)token));
}
// <symbol literal> ::= hashedString
if (token is HashedStringToken) // #'example'
{
return(new SymbolLiteralNode(parent, (HashedStringToken)token));
}
// <character literal> ::= quotedCharacter
if (token is CharacterToken) // $e
{
return(new CharacterLiteralNode(parent, (CharacterToken)token));
}
// <selector literal> ::= quotedSelector
if (token is QuotedSelectorToken) // #example ..or.. #example: ..or.. #example:example: ..or.. #+
{
return(new SelectorLiteralNode(parent, (QuotedSelectorToken)token));
}
// <number literal> ::= ['-'] <number>
if (token is NegativeSignToken)
{
return(this.ParseNegativeNumericLiteralNode(parent, (NegativeSignToken)token));
}
// <number> ::= integer | float | scaledDecimal
if (token is SmallIntegerToken)
{
return(new SmallIntegerLiteralNode(parent, (SmallIntegerToken)token, null));
}
if (token is LargeIntegerToken)
{
return(new LargeIntegerLiteralNode(parent, (LargeIntegerToken)token, null));
}
if (token is FloatEToken)
{
return(new FloatELiteralNode(parent, (FloatEToken)token, null));
}
if (token is FloatDToken)
{
return(new FloatDLiteralNode(parent, (FloatDToken)token, null));
}
if (token is ScaledDecimalToken)
{
return(new ScaledDecimalLiteralNode(parent, (ScaledDecimalToken)token, null));
}
// <array literal> ::= '#(' <array element>* ')'
// <array element> ::= <literal> | identifier
if (Parser.IsLiteralArrayPrefix(token))
{
return(this.ParseArrayLiteral(parent, (SpecialCharacterToken)token));
}
this.ResidueToken = token;
return(null);
}
