void RequireTokenType(Token.Types type)
{
if (!this.TokenIs (type)) {
this.RequireTokenError (
new Token.Types?[] { type },
new string[] { },
this.CurrentToken ());
}
}
bool TokenIs(Token.Types type, string content = null)
{
if (!Finished ()) {
var token = this.CurrentToken ();
return token.Type == type && (content == null || token.Content == content);
} else {
return false;
}
}
void RequireTokenExactly(Token.Types type, string content)
{
if (!this.TokenIs (type, content)) {
this.RequireTokenError (
new Token.Types?[] { type },
new string[] { content },
this.CurrentToken ());
}
}
void RequireTokenError(
IEnumerable<Token.Types?> types, IEnumerable<string> contents, Token actualToken)
{
var possibleTypes = types.Where (type => type != null);
var possibleContents = contents.Where (content => content != null);
string expectation = "";
if (possibleContents.Count () == 0) {
if (possibleTypes.Count () == 0) {
Utils.Panic ();
} else if (possibleTypes.Count () == 1) {
expectation = String.Format ("Expected a {0}", possibleTypes.First ().ToString ().ToLower ());
} else {
expectation = String.Format (
"Expected one of {0}",
String.Join (", ", possibleTypes.Select (type => type.ToString ().ToLower ())));
}
} else if (possibleContents.Count () == 1) {
expectation = String.Format ("Expected '{0}'", possibleContents.First ());
} else {
expectation = String.Format (
"Expected one of {0}",
String.Join (", ", possibleContents.Select (content => "'" + content + "'")));
}
string actualInput;
if (actualToken != null) {
actualInput = String.Format ("but got '{0}'", actualToken.Content);
} else {
actualInput = "but reached the end of input";
}
var message = String.Format ("{0}, {1}.", expectation, actualInput);
this.RaiseError (message);
}
void NextToken()
{
this.lastToken = this.CurrentToken ();
this.tokenIndex++;
}
void ConsumeToken(Token.Types type, string content)
{
this.RequireTokenExactly (type, content);
this.NextToken ();
}
Token TokenizePred(Token.Types type, Func<char, bool> pred)
{
int startPos = this.pos;
while (!this.Finished() && pred(this.CurrentChar()))
{
this.NextChar();
}
return new Token()
{
StartPos = startPos,
EndPos = this.pos - 1,
Type = type,
Content = this.source.Content.Substring(startPos, this.pos - startPos)
};
}