Parse Text File with Qt

[ChrisW67]

Is there an easier way? For example, will QRegExp be capable of doing my job?

Bits of the task certainly. However, matching whole, nested compund structures where deelimiters must be balanced rapidly becomes very difficult.

I do not want to parse the text file from scratch (e.g. use QFile and QString). I am interested in QLALR. But it is hard to start with QLALR due to the poor documentations.
Traditional lex/yacc is powerful. However, it requires additional learning process for a person (like me) who never use it before. I am not sure whether it is worth learning lex/yacc for this simple job I have.

Fair call on the QLALR documentation... there's a high level of assumed knowledge in the examples that are around. You might like the better documented GOLD Parsing System.

I think the effort of learning lex/yacc, or the theory of operation, is well worth it for the potential to help in many future projects. However, time and effort required to learn this must be offset by your circumstance. Are you parsing one file, or thousands? Are they very variable (numbers of net-lists etc.)? Is the grammar we can see only a subset of a larger possible grammar?

[rhf417]

I did some research on the parser generator these days and found a good tool - "Visual Parser++" which is easy to learn. I am working under windows and C++. I feel that Visual Parser++ is very convenient to use. I have parsed my text file with it successfully. The only drawback is that there will be no support since Sandstone does not exist anymore.

Basically, the text file shown above is the only file I need to handle. I only need to parse one file at a time, not thousand of them. The grammar you can see here is not all, but the rest are very similar. I would like to spend more time to learn Lex/Yacc and QLALR later, but not now, I guess.

For me, tbscope's method is the one I would like to apply to my current project. It looks quite straightforward and does not require any additional tools. Thank you very much. Thanks all for all the valuable advices.

[wysota]

Basically, the text file shown above is the only file I need to handle. I only need to parse one file at a time, not thousand of them.

It's not the number of files you wish to parse at a time that may be a problem. The problem is you may want to parse different files (with different contents) in general.

[rhf417]

It's not the number of files you wish to parse at a time that may be a problem. The problem is you may want to parse different files (with different contents) in general.

I understand. If there are many different types of files to parse, a parser generator would be the better choice.

[squidge]

Be careful and do your research. I've fallen into this trap before - build a parser for the files I had that worked brilliantly. Then, a month later I had some more files and it only parsed one of them correctly. I didn't then have the time to fix the program properly to parse them all, so hacked it up to make it work. Do that a few times and you have a nightmare of an application to maintain or a range of application that parse different variations.

Its so much easier to do it right from the beginning.

[markanth]

Does anyone know where to find an old copy of Visual Parse++? It is a great tool to teach parsing. We have been searching for it, and all we can find are URLs that point to the no longer existing Sandstone site.