Laufeyjarson writes…

This Practice starts off a new section, on documentation.  I think there’s at least one point in this chapter I disagree with Mr. Conway’s conclusions, but we’ll get there presently.  In general, I think he has valuable things to say, and the issues are worth thinking about and deciding on.

Documentation is important, and it’s something many of us are terrible at.

The first Practice he suggests is to be aware there are several kinds of documentation, and to separate the user documentation from the technical documentation. Read the rest of this entry »

The PBP suggests applying a label to each loop that is exited explicitly.  A simple request, but one I usually find vexing. Read the rest of this entry »

This Practice is to encourage the use of a for loop instead of while plus a counter.  It reminds us of redo, a Perl feature I always forget which lets us do the loop over at this iterator.  If the only place the while loop does not increment is to try again, a redo fits perfectly.  If the loop has to do more complex changes to the iterator – back up, start over at zero, whatever – then you’ll sill need the more complex while+counter. Read the rest of this entry »

Mr. Conway disagrees with some of my college professors again.  He says that it is not useful to abuse loop constructs just to consolidate control in a single location.  He is a hero for this stance. Read the rest of this entry »

This suggestion seems oddly worded to me, although I’m not sure I can think of a better one.  The book says, “Reject as many iterations as possible, as early as possible.”  Luckily, it goes on to explain what this means, as that isn’t – at least to  me – terribly clear.  It winds up being an extension of “coding in paragraphs” and is more about how to organize your code than how to format it.  I think I agree with this and do it all the time, despite having had many college professors claim it is the root of all evil. Read the rest of this entry »

This suggestion from the PBP is simple: Don’t use do … while loops.  The reasoning is good and readable alternatives are provided.  I wind up having no trouble with this suggestion, although I wasn’t as happy with it when I first read it. Read the rest of this entry »

Mr. Conway suggests that you can cascade uses of the ternary (?:) operator instead of an if-elsif-else chain.  He feels this is much more readable.  I strongly disagree. Read the rest of this entry »

The idea behind this Best Practice is to explain how a table lookup can be used instead of an if/elsif/elsif/elsif/elsif/else block to make selections from a set of constants.  This is almost always a good choice! Read the rest of this entry »

The PBP say “Avoid cascading an if.”  At first glance, this sounds like a pretty harsh suggestion.  As it turns out, I rarely ever have any issue following this suggestion.  Well organized code seems not to need long if/elsif/elsif/elsif/elsif/else blocks. Read the rest of this entry »

Mr. Conway suggests the very firm, “Never modify $_ in a list function.”  I’m torn on this. Read the rest of this entry »