Posts Tagged 'teaching'

Code Quality

An interesting essay on Code Quality by Hew Wolff, over at the Pragmatic Programmers, in their online magazine. The basic thesis is that ‘Good Code Tells the Truth’ (that’s the title). It resonated with me because a week or two back I was looking at an Access/VBA application (not one of mine!). The code in this application was, if I might be frank, dire:

  • no indentation in a lot of procedures
  • no splitting of long SQL strings over multiple lines (when I did reformat one, it ran to 8 lines)
  • no useful comments at either module/form or procedure level
  • form controls not renamed (one form had buttons called Command27, Command28, Command66, Command139 – see what I mean?)
  • obscure variable names – for example, in one procedure, U3, D3, d4, SN3, FN3
  • using 0 and -1 for False and True (why?)
  • copy-paste-and-tweak repetition (e.g. to re-initialize a form).

The piece de resistance was a SELECT-INTO query that created a column using this expression:

[id]-[id]-1

So, arithmetic on Ids? As far as I can tell, this converts an Id value into -1 (presumably treated as True), but leaves Null values as Null, since arithmetic expressions involving Nulls equal Null. Is this a common Access programming technique? Even if it is, couldn’t it be wrapped in a function called something like NonNullToTrue (although this could not have argument or result types more specific than Variant).

This might (or might not) be a clever trick, but not considering the possibility of other people finding it confusing indicates of a poor approach to programming. What the essay mentioned earlier is saying, and what I’m agreeing with here, is that software development is as much about communication of a solution as it is about that solution just working.

Learning VBA

Interesting post (and comments) over at Daily Dose of Excel (referencing another post). Basically saying that people should be learning and using (a bit of) VBA, as part of their basic efficiency/productivity – assuming they use Office apps, of course. For example, you wonder how many people copy-and-paste quantities of data manually (probably making mistakes) on a regular basis, when a few lines of code would do it for them.

Unfortunately, it is part of our culture that programming is regarded as something terribly technical and obscure, not for ordinary people. Microsoft themselves are at fault for putting ever more layers of user interface in front of the application functionality. Lots of PC users do not know what a Command Prompt is. I admit that VBA as a language is a bit quirky and inconsistent (the Set Keyword, for example), but it’s not unusable.

There’s a similar issue over in the domain of XML documentation. There are technical writers (‘technical’, note) who feel that everything should be entirely wrapped up in a GUI. This might be feasible if you are prepared to do what the tools let you do, and nothing else. But I think having some knowledge of the underlying languages is helpful.

It also allows you to use the many free tools, which tend to be light on GUIs. For example, a set of XML document files on disk can be queried (and even updated) using the XQuery language, effectively turning the files into a content database. XQuery is a very clean, functional language, with a SELECT-like construct to do the querying (much easier than VBA!). There are free (versions of) tools that index files and run queries.

So, yes, I think that there should be greater encouragement for ‘serious’ users of tools to roll their sleeves up and get into some (gentle or not so gentle) programming. At least they’d appreciate a bit more what developers do!


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