/// <summary>
/// Converts a given source text into a stream of tokens that can be consumed to create a syntax tree.
/// </summary>
/// <param name="source">The source text to analyze.</param>
/// <returns>TokenStream.</returns>
public static TokenStream Tokenize(SourceText source)
{
var tokenSet = new TokenStream(source.Text);
source.SkipWhitespace();
while (source.HasData)
{
SourceLocation location;
// Comments
// -------------------
if (source.CheckCursor(SR.IsCommentGlyph))
{
var text = source.NextComment(out location);
tokenSet.Enqueue(new CommentToken(text, location));
}
// Flow Controler characer (non-text entities)
// -------------------
else if (source.CheckCursor(SR.IsControlGlyph))
{
var text = source.NextControlPhrase(out location);
tokenSet.Enqueue(new ControlToken(text.ToTokenType(), text, location));
}
// Named fields
// ---------------------------------
else if (source.CheckCursor(SR.IsStartOfNameGlyph))
{
var text = source.NextName(out location);
tokenSet.Enqueue(Lexer.CharactersToToken(text, location));
}
// Numbers
// ----------------------------------
else if (source.CheckCursor(SR.IsStartOfNumberGlyph))
{
var text = source.NextNumber(out location);
tokenSet.Enqueue(NumberToken.FromSourceText(text, location));
}
// Strings
// ----------------------------------
else if (source.CheckCursor(SR.IsStringDelimiterGlyph))
{
var text = source.NextString(out location);
tokenSet.Enqueue(new StringToken(text, location));
}
else
{
// who the heck knows, just fail
location = source.RetrieveCurrentLocation();
throw new GraphQLSyntaxException(
location,
$"Unexpected character: '{source.Peek()}'");
}
source.SkipWhitespace();
}
tokenSet.Enqueue(EndOfFileToken.Instance);
return(tokenSet);
}
