public Token NextToken()
{
// if we had a token waiting, just return it
Token ans = null;
// otherwise... process some text.
skipWS();
if (!OutOfChars)
{
char c = nextChar();
switch (c)
{
case '#': // comment
getToEOL();
ans = new Token(TokenType.TOK_EOL, null);
break;
case '\n': // end of line/statement
ans = new Token(TokenType.TOK_EOL, null);
break;
case ':': // start of free-form string arg
ans = new Token(TokenType.TOK_STRING, getToEOL());
break;
default: // must be a keyword or identifier...
ans = processIdentifier(c);
break;
}
}
return ans;
}
private static void parseIdentifier(Tokenizer t, Diagram d, Token first)
{
// OK, we got an identifier... let's make sure the Diagram knows about it...
Actor left = d.MaybeNewActor(first.data);
// Valid continuations are:
// EOL ... just define the actor so we have a good order
// STRING EOL ... define the actor with a display name
// TO ID [DASHED] [STRING] EOL ... define an arrow
Token second = t.NextToken();
switch (second.type)
{
case TokenType.TOK_EOL: // no problem here...
break;
case TokenType.TOK_STRING: // giving a display name...
left.DisplayName = second.data;
break;
case TokenType.TOK_TO: // defining an arrow...
parseArrow(t, d, left);
break;
default: // something went wrong here...
d.HasErrors = true;
break;
}
}
// process characters and figure out if it's a keyword or not.
private Token processIdentifier(char first)
{
Token ans = null;
var sb = new StringBuilder();
sb.Append(first);
char c = nextChar();
while (c != ':' && !Char.IsWhiteSpace(c))
{
sb.Append(c);
c = nextChar();
}
ungetChar(); // push back whatever char we stopped on.
// now we have an identifier... we need to see if it's a keyword...
string ident = sb.ToString();
switch (ident.ToUpper())
{
case "TO":
ans = new Token(TokenType.TOK_TO, ident);
break;
case "SELF":
ans = new Token(TokenType.TOK_SELF, ident);
break;
case "DASHED":
ans = new Token(TokenType.TOK_DASHED, ident);
break;
case "TITLE":
ans = new Token(TokenType.TOK_TITLE, ident);
break;
case "NOTE":
ans = new Token(TokenType.TOK_NOTE, ident);
break;
default:
ans = new Token(TokenType.TOK_IDENTIFIER, ident);
break;
}
return ans;
}