Learning the Progress 4GL¶
The Progress 4GL language is sometimes also called Progress OpenEdge or the Progress "Advanced Business Language" (ABL). Though there are newer versions, they are all just incremental differences over the original 4GL language. The new names are a marketing attempt to get people to get past the negative connotations that 4GL technology has in the market.
The Progress 4GL is strange, proprietary, inconsistent with many quirks and rough edges. It doesn't always make sense, especially if you learned to program in a more modern language such as Java. As you start to explore the 4GL, if you have access to experienced 4GL or FWD developers, they can be invaluable. Ask questions to speed the process by which you properly understand the language.
To "ramp-up" on the 4GL:
1. Download the Progress 4GL documentation. There are 2 versions of interest:
Progress 4GL v9.1E: http://download.psdn.com/documentation/openedge/pdf_zip_files/91e/progress_documentation_9.1e_pdfs.zip
Progress ABL v11.7: https://community.progress.com/community_groups/openedge_general/m/documents/3278/download
Most of your work will be done with the latest version of the documentation. However, the v9.1 versions have 2 documents that don't exist in the later versions:
- Language Tutorial for Character
- Progress Handbook
For this reason, it is important that you download both versions of the v9.1E documentation.
2. Read the tutorial Inside the 9.1E docs archive, you will find a PDF called ltu.pdf ("Language Tutorial for Character"). This is a tutorial to introduce the 4GL programming language for a Unix environment. Read this tutorial and try to get the basic idea of what 4GL code looks like and means. You aren't expected to be an expert, but it is important to be able to read code and write testcases in the language. Although GUI may also be of interest, the core of the language can be learned with just the this tutorial.
3. Read the handbook. Inside the 9.1E docs archive, you will find a PDF called proghand.pdf ("Progress Handbook"). This describes more detail on certain important language topics such as transaction processing and how queries work.
It is very useful to have the Progress 4GL Reference manual open while reading (dvref.pdf in either download). This allows you to quickly read in more depth about specific language statements, built-in functions or other features.
4. Write test code. To ensure that you have a valid understanding of the language, you need to read existing code or write some sample programs.
Don't spend too much time on any particular topic as the idea is just for you to be able to read and write basic programs in the 4GL language. You can use an existing Progress OpenEdge developer system if you have access to one. Or you can use FWD to convert and run these programs. It is important that you don't use any 4GL features that are unsupported by FWD, but otherwise it should work well.
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