Java Tokenization: Treat Anything Separated by an Underscore as One Word

Question

I have a very simple tokenizer using StreamTokenizer, which will convert mathematical expressions into their individual components (below). The problem that I am having, is if there is a variable in the expression called T_1, it will split into [T,_,1], which I would like to return as [T_1].

I have attempted to use a variable to check if the last character was an underscore, and if so, append the underscore onto the list.Size-1, but it seems like a very clunky and inefficient solution. Is there a way to do this? Thanks!

        StreamTokenizer tokenizer = new StreamTokenizer(new StringReader(s));
        tokenizer.ordinaryChar('-'); // Don't parse minus as part of numbers.
        tokenizer.ordinaryChar('/'); // Don't parse slash as part of numbers.
        List<String> tokBuf = new ArrayList<String>();
        while (tokenizer.nextToken() != StreamTokenizer.TT_EOF) //While not the end of file 
        {
            switch (tokenizer.ttype) //Switch based on the type of token
            {
            case StreamTokenizer.TT_NUMBER: //Number
                tokBuf.add(String.valueOf(tokenizer.nval));
                break;
            case StreamTokenizer.TT_WORD: //Word
                tokBuf.add(tokenizer.sval);
                break;
            case '_':
                tokBuf.add(tokBuf.size()-1, tokenizer.sval);
                break;
            default: //Operator
                tokBuf.add(String.valueOf((char) tokenizer.ttype));
            }
        }

        return tokBuf;

Answer 1

This is what you want.

tokenizer.wordChars('_', '_');

This makes the _ recognizable as part of a word.

Addenda:

This builds and runs:

public static void main(String args[]) throws Exception {
    String s = "abc_xyz abc 123 1 + 1";
    StreamTokenizer tokenizer = new StreamTokenizer(new StringReader(s));
    tokenizer.ordinaryChar('-'); // Don't parse minus as part of numbers.
    tokenizer.ordinaryChar('/'); // Don't parse slash as part of numbers.
    tokenizer.wordChars('_', '_'); // Don't parse slash as part of numbers.


    List<String> tokBuf = new ArrayList<String>();
    while (tokenizer.nextToken() != StreamTokenizer.TT_EOF) //While not the end of file 
    {
        switch (tokenizer.ttype) //Switch based on the type of token
        {
        case StreamTokenizer.TT_NUMBER: //Number
            tokBuf.add(String.valueOf(tokenizer.nval));
            break;
        case StreamTokenizer.TT_WORD: //Word
            tokBuf.add(tokenizer.sval);
            break;
        default: //Operator
            tokBuf.add(String.valueOf((char) tokenizer.ttype));
        }
    }
    System.out.println(tokBuf);
}

run:
[abc_xyz, abc, 123.0, 1.0, +, 1.0]