public static string LexStringLiteral(LexReader reader, IDictionary <char, char> basicEscapes, IDictionary <char, Func <LexReader, string> > advancedEscapes, string openingSequence, string closingSequence, bool escapeClosingByDoubling)
{
var builder = new StringBuilder();
if (!reader.ContinuesWith(openingSequence))
{
return(null);
}
var startingPos = reader.GetPosition();
string doubleClosingSequence = closingSequence + closingSequence;
reader.Consume(openingSequence.Length);
while (true)
{
if (reader.EndOfFile())
{
throw new LexException(reader.GetPosition(), "Unexpected end of string literal.").AddPosition(startingPos, "Start of string literal").Freeze();
}
if (escapeClosingByDoubling && reader.ContinuesWith(doubleClosingSequence))
{
reader.Consume(doubleClosingSequence.Length);
builder.Append(doubleClosingSequence);
}
else if (reader.ContinuesWith(closingSequence))
{
reader.Consume(closingSequence.Length);
return(builder.ToString());
}
else if ((basicEscapes != null || advancedEscapes != null) && reader.ContinuesWith("\\"))
{
reader.Consume(1);
char escape = reader.ConsumeChar();
char replacement;
Func <LexReader, string> replacementFunc;
if (basicEscapes.TryGetValue(escape, out replacement))
{
builder.Append(replacement);
}
else if (advancedEscapes.TryGetValue(escape, out replacementFunc))
{
builder.Append(replacementFunc(reader));
}
else
{
throw new LexException(reader.GetPosition(-1), @"Unrecognized escape sequence: ""\{0}"".".Fmt(escape));
}
// could introduce support for other behaviours on unrecognized \x, such as no-escape (\x => \x) or as-is escape (\x => x)
}
else
{
builder.Append(reader.ConsumeChar());
}
}
}
public static string LexStringLiteral(LexReader reader, IDictionary<char, char> basicEscapes, IDictionary<char, Func<LexReader, string>> advancedEscapes, string openingSequence, string closingSequence, bool escapeClosingByDoubling)
{
var builder = new StringBuilder();
if (!reader.ContinuesWith(openingSequence))
return null;
var startingPos = reader.GetPosition();
string doubleClosingSequence = closingSequence + closingSequence;
reader.Consume(openingSequence.Length);
while (true)
{
if (reader.EndOfFile())
throw new LexException(reader.GetPosition(), "Unexpected end of string literal.").AddPosition(startingPos, "Start of string literal").Freeze();
if (escapeClosingByDoubling && reader.ContinuesWith(doubleClosingSequence))
{
reader.Consume(doubleClosingSequence.Length);
builder.Append(doubleClosingSequence);
}
else if (reader.ContinuesWith(closingSequence))
{
reader.Consume(closingSequence.Length);
return builder.ToString();
}
else if ((basicEscapes != null || advancedEscapes != null) && reader.ContinuesWith("\\"))
{
reader.Consume(1);
char escape = reader.ConsumeChar();
char replacement;
Func<LexReader, string> replacementFunc;
if (basicEscapes.TryGetValue(escape, out replacement))
builder.Append(replacement);
else if (advancedEscapes.TryGetValue(escape, out replacementFunc))
builder.Append(replacementFunc(reader));
else
throw new LexException(reader.GetPosition(-1), @"Unrecognized escape sequence: ""\{0}"".".Fmt(escape));
// could introduce support for other behaviours on unrecognized \x, such as no-escape (\x => \x) or as-is escape (\x => x)
}
else
{
builder.Append(reader.ConsumeChar());
}
}
}
public static string Lex0xHexInteger(LexReader reader)
{
if (!reader.ContinuesWith("0x") && !reader.ContinuesWith("0X"))
return null;
reader.Consume(2);
string result = reader.ConsumeStringWhile(IsHexadecimalDigit);
if (result.Length == 0)
throw new LexException(reader.GetPosition(-2), "Hexadecimal integers starting with the \"0x\" prefix must have at least one hex digit.");
return (result.Length == 0) ? null : result;
}
public override Token ParseToken(LexReader reader)
{
foreach (var tokenstr in _operators)
{
if (reader.ContinuesWith(tokenstr))
{
var start = reader.GetPosition();
reader.Consume(tokenstr.Length);
return(new BuiltinToken(start, reader.GetPosition(), tokenstr));
}
}
return(null);
}
public static string Lex0xHexInteger(LexReader reader)
{
if (!reader.ContinuesWith("0x") && !reader.ContinuesWith("0X"))
{
return(null);
}
reader.Consume(2);
string result = reader.ConsumeStringWhile(IsHexadecimalDigit);
if (result.Length == 0)
{
throw new LexException(reader.GetPosition(-2), "Hexadecimal integers starting with the \"0x\" prefix must have at least one hex digit.");
}
return((result.Length == 0) ? null : result);
}
