func lexUntilClosing(l *lex.Lexer, styp lex.ItemType,
sfn lex.StateFn) lex.StateFn {
l.AcceptUntil(isClosingBracket)
r := l.Next()
if r == lex.EOF {
return l.Errorf("Unexpected end of subject")
}
if r == '>' {
l.Emit(styp)
return sfn
}
return l.Errorf("Invalid character %v found for itemType: %v", r, styp)
}
// Assumes that the current rune is '_'.
func lexBlankNode(l *lex.Lexer, styp lex.ItemType,
sfn lex.StateFn) lex.StateFn {
// RDF Blank Node.
// TODO: At some point do checkings based on the guidelines. For now,
// just accept everything until space.
l.AcceptUntil(isSpace)
r := l.Peek()
if r == lex.EOF {
return l.Errorf("Unexpected end of subject")
}
if isSpace(r) {
l.Emit(styp)
return sfn
}
return l.Errorf("Invalid character %v found for itemType: %v", r, styp)
}
// lexFilterFuncInside expects input to look like ("...", "...").
func lexFilterFuncInside(l *lex.Lexer) lex.StateFn {
l.AcceptRun(isSpace)
l.Ignore() // Any spaces encountered.
for {
r := l.Next()
if isSpace(r) || r == ',' {
l.Ignore()
} else if r == leftRound {
l.Emit(itemLeftRound)
} else if r == rightRound {
l.Emit(itemRightRound)
return lexFilterInside
} else if isEndLiteral(r) {
l.Ignore()
l.AcceptUntil(isEndLiteral) // This call will backup the ending ".
l.Emit(itemFilterFuncArg)
l.Next() // Consume " and ignore it.
l.Ignore()
} else {
return l.Errorf("Expected quotation mark in lexFilterFuncArgs")
}
}
}
func lexUidNode(l *lex.Lexer, styp lex.ItemType, sfn lex.StateFn) lex.StateFn {
l.AcceptUntil(isSpace)
r := l.Peek()
if r == lex.EOF {
return l.Errorf("Unexpected end of uid subject")
}
in := l.Input[l.Start:l.Pos]
if !strings.HasPrefix(in, "_uid_:") {
return l.Errorf("Expected _uid_: Found: %v", l.Input[l.Start:l.Pos])
}
if _, err := strconv.ParseUint(in[6:], 0, 64); err != nil {
return l.Errorf("Unable to convert '%v' to UID", in[6:])
}
if isSpace(r) {
l.Emit(styp)
return sfn
}
return l.Errorf("Invalid character %v found for UID node itemType: %v", r,
styp)
}