protected int stopCharIndex(int pos) {
            while (pos < string.length()) {
                var ch = string.charAt(pos);
                if (Character.isWhitespace(ch)) return pos;
                if (ch == ',') return pos;
                if (ch == ']') return pos;
                if (ch == '}') return pos;
                if (ch == ':') return pos;
                pos++;
            }
            return pos;
        }
Derives the tensor type from the first address string in the given tensor string
vespajlib/src/main/java/com/yahoo/tensor/TensorParser.java