private List<RegionResult> GetRegionBlocks()
{
var result = new List<RegionResult>();
while (true)
{
RegionResult region;
switch (_current.Token)
{
case Token.Eof: return result;
case Token.Do: // do-while has two blocks
region = ParseBlock();
_current = _lexer.GetToken();
if (_current.Token == Token.While)
{
var whileRegion = ParseBlock();
var doWhile = region.Combine(whileRegion);
result.Add(doWhile);
_current = _lexer.GetToken();
break;
}
result.Add(region);
break;
default:
region = ParseBlock();
result.Add(region);
_current = _lexer.GetToken();
break;
}
}
}
private RegionResult ParseBlock()
{
var start = _current.Start;
// first token is Left curly bracket.
bool block = _current.Token == Token.LeftBracket;
while (_current.Token != Token.Eof)
{
_current = _lexer.GetToken();
if ((!block && _current.Token == Token.SemiColon)
|| (block && _current.Token == Token.RightBracket)
|| _current.Token == Token.Eof)
{
return new RegionResult
{
Offset = start,
Length = _current.End - start
};
}
if (_current.Token == Token.LeftParenthese)
{
var isComplete = SkipScope(Token.LeftParenthese, Token.RightParenthese);
if (_current.Token == Token.Eof)
{
return new RegionResult
{
Offset = start,
Length = _current.End - start,
IsCompleteBlock = isComplete
};
}
continue;
}
if (_current.Token == Token.LeftBracket)
{
bool isComplete = SkipScope(Token.LeftBracket, Token.RightBracket);
return new RegionResult
{
Offset = start,
Length = _current.End - start,
IsCompleteBlock = isComplete
};
}
}
throw new InvalidOperationException(string.Format("{0} should never reach this point.", typeof(RegionParser).Name));
}
public List<RegionResult> Parse(string code)
{
_lexer = new ScriptLexer(code);
_current = _lexer.GetToken();
return GetRegionBlocks();
}
private bool SkipScope(int leftToken, int rightToken)
{
if (_current.Token != leftToken)
{
throw new ArgumentException("Invalid use of SkipBlock method, current token should equal left token parameter");
}
var scope = new Stack<int>();
scope.Push(1);
while (_current.Token != Token.Eof)
{
_current = _lexer.GetToken();
if (_current.Token == leftToken)
{
scope.Push(1);
}
if (_current.Token == rightToken)
{
scope.Pop();
}
if (scope.Count == 0)
{
return true;
}
}
return false;
}