/// <summary>
/// Converts the <see cref="string"/> value into Lua expression.
/// </summary>
/// <param name="value">The value to convert.</param>
/// <param name="delimiter">The delimiter used to start the Lua string expression.</param>
/// <remarks>
/// Lua supports starting a string expression with <c>'</c>, <c>"</c>, or <c>[====[</c>, where in
/// the last case, there can be any (including 0) count of equal signs.
/// </remarks>
public static string ToString(string value, string delimiter)
{
var delm = StringDelimiterInfo.FromStartDelimiter(delimiter);
using (var writer = Utility.CreateStringWriter((value?.Length ?? 0) + delimiter.Length * 2))
{
WriteEscapedString(value, delm, writer);
return(writer.ToString());
}
}
internal static void WriteEscapedString(string value, StringDelimiterInfo delimiter, TextWriter writer)
{
Debug.Assert(delimiter != null);
if (string.IsNullOrEmpty(value))
{
writer.Write(delimiter.StartDelimiter);
writer.Write(delimiter.EndDelimiter);
return;
}
if (delimiter.IsBracket)
{
if (value[0] == '\n')
{
throw new InvalidOperationException(@"String value cannot start with \n when using bracket as delimiter.");
}
if (value.Contains(delimiter.EndDelimiter))
{
throw new InvalidOperationException(@"String value cannot contain closing long bracket sequence of the proper level.");
}
writer.Write(delimiter.StartDelimiter);
writer.Write(value);
writer.Write(delimiter.EndDelimiter);
}
else
{
writer.Write(delimiter.StartDelimiter);
foreach (var c in value)
{
switch (c)
{
case '\\':
writer.Write("\\");
break;
case '\a':
writer.Write("\\a");
break;
case '\b':
writer.Write("\\b");
break;
case '\f':
writer.Write("\\f");
break;
case '\n':
writer.Write("\\n");
break;
case '\r':
writer.Write("\\r");
break;
case '\t':
writer.Write("\\t");
break;
case '\v':
writer.Write("\\v");
break;
case '\"' when delimiter.IsDoubleQuote:
writer.Write("\\\"");
break;
case '\'' when delimiter.IsSingleQuote:
writer.Write("\\\'");
break;
default:
writer.Write(c);
break;
}
}
writer.Write(delimiter.EndDelimiter);
}
}
public static void WriteString(TextWriter writer, string value, string delimiter)
{
var delm = StringDelimiterInfo.FromStartDelimiter(delimiter);
WriteEscapedString(value, delm, writer);
}
private string ReadComment()
{
if (!Consume("--"))
{
return(null);
}
var equalSigns = -1;
var bracketLevel = -1;
if (Consume('['))
{
equalSigns = 0;
while (Consume('='))
{
equalSigns++;
}
if (Consume('['))
{
// Read: --[==...==[
bracketLevel = equalSigns;
}
}
// Parse / skip comment
StringBuilder sb = null;
if (PreserveComments)
{
sb = new StringBuilder("--");
}
if (bracketLevel < 0)
{
// Single-line comment
// -- Comment
if (sb != null)
{
// Restore [ and = that we have already read.
if (equalSigns >= 0)
{
sb.Append('[');
if (equalSigns > 0)
{
sb.Append('=', equalSigns);
}
}
}
ConsumeUntil('\r', '\n', sb);
Consume();
}
else
{
// Multi-line comment
// --[==[ Comment
// Comment
// Comment]==] comment
var bracket = StringDelimiterInfo.FromBracketLevel(bracketLevel);
sb?.Append(bracket.StartDelimiter);
while (!BufferEof)
{
ConsumeUntil(']', char.MinValue, sb);
if (Consume(bracket.EndDelimiter))
{
sb?.Append(bracket.EndDelimiter);
// right bracket detected
// skip current line
ConsumeUntil('\r', '\n', sb);
Consume();
break;
}
else
{
// ordinary right bracket.
sb?.Append((char)Consume());
}
}
}
return(sb != null?sb.ToString() : string.Empty);
}