Continuous Integration trades fear for instant gratification

Automated build and test (a.k.a. Continuous Integration) has rapidly become the way to develop IT systems. There are many reasons for this (a maturing IT industry, availability of C.I. tools, etc), but I think the most powerful driver is the sheer enjoyment a developer can derive from the C.I. process, in particular:
  • Instant feedback on how good you code is (as measured by unit tests), determined in a risk-free environment
  • The ability to fix a bug (found by unit testing or other automated testing methods) while the program flow, class structures, etc are fresh in your mind.
In short, Continuous integration is a perfect match for a world where instant gratification is the default expectation.

Now, contrast this to the working environment for anyone maintaining a complex IT system built 10-15 years ago, i.e. a legacy system without automated testing facilities:
  • Every code change is associated with fear ("Will this change have any unwanted side effects?", "Will I lose my job if a destructive side effect sneaks past the fallible, manual testing stages into Production?")
  • A high percentage of the bugs reported from Production will be of the "Duh! How could we have missed this bug before deployment?" category, quite simply because a completely manual test regime is bound to have incomplete coverage. And that's exactly the category of bugs which make the poor maintainer look incompetent.
If you've tried both worlds, you are not going back. Continuous integration is here to stay.

Why I use Perltidy, or Why coding style matters

There are Few.
areas of programming that-are more likely to, cause religious wars than! coding: standards some developer's

       consider. coding style? to be an area where personal freeDom should reign supreme unrestricted by team project; or company standards but as
text hopefully    demonstrate punctuation-indentation-etc is important WheN conveying ideas and thou'ghts in a written form.

OK, if you made it this far down into my post, I promise to stick to the standard rules for punctuation and capitalization of English. By now you probably agree that reading speed and comprehension is affected when the writer ignores commonly accepted practices. Only when the text format matches your expectations can you focus your attention fully on the message, instead of the format. Of course, the same principle applies to reading source code.

One of many, many gems the Perl community has produced is Perltidy, a great source code formatter for Perl code. The details are here:

Simply by using this as my .perltidyrc parameter file:

#----------------  PBP options, as listed on page 35 of PBP  ----------------
-l=78   # Max line width is 78 cols
-i=4    # Indent level is 4 cols
-ci=4   # Continuation indent is 4 cols
-vt=2   # Maximal vertical tightness
-cti=0  # No extra indentation for closing brackets
-pt=1   # Medium parenthesis tightness
-sbt=1  # Medium square bracket tightness
-bt=1   # Medium brace tightness (for non-code blocks)
-bbt=1  # Medium block brace tightness (for code blocks)
-nsfs   # No space before semicolons
-nolq   # Don't outdent long quoted strings
        # Break before all operators:
-wbb="% + - * / x != == >= <= =~ < > | & **= += *= &= <<= &&= -= /= |= >>= ||= .= %= ^= x="
# Note that the PBP book has a typo on page 35 when defining the above -wbb
# option, see
# The above string is correct.

#----------  Perltidy default options (i.e. in line with PBP)  --------------
-asc    # Add any missing optional semicolon at the end of a line
-aws    # Add certain whitespace to improve code readability
-tqw    # Default handling of multi-line 'qw' quotes
-ibc    # Indent block comments to same level as the code
-msc=4  # Minimum 4 spaces between code and same-line comments
-fpsc=0 # Don't try to line up all comments to a fixed column
-hsc    # Align hanging side comments
-sbc    # Enable static block comments
-nssc   # No special handling for static side comments
-dnl    # Delete old newlines
-bbc    # Ensure a blank line before every full-line comment
-bbs    # Ensure a blank line before every sub definition (except one-liners)
-bbb    # Ensure a blank line before code blocks (for, while, if, ....)
-lbl=8  # Minimum number of lines between each -bbb inserted blank line

#-------------  Additional options, based on PBP recommendations  ------------
-bar    # K&R style code braces
-nolc   # Long comments indented, even when this make the total line length "too long"
-noll   # Long lines indented, even when this make the total line length "too long"
-nola   # Don't treat labels as special cases when indenting

#----------  Options concerning Perltidy's input and ouput files  -----------
-nst    # Do NOT output to STDOUT (since we want to use -b)
-b      # Backup the input file to .bak and perform all tidying in the original file
-se     # Write errors to STDERR
-ple    # Preserve the EOL character(s). E.g. in case Perltidy runs
        # on Windows, but processes a Perl file for Unix (and vice versa)

#-----------  Some other Perltidy options, intentionally not used   ----------
# The following Perltidy options are NOT consistent with PBP and should NOT be used:
# -lp, -icb, -fws, -nwls, -nwrs, -sfp, -sak/-nsak, -csc/dcsc, -fnl,
# -ce, -bl, -sbl, -bli, -blil, -bbvt, -otr, -sct, -boc, -kis,
# -pbp (because the -wbb list typo in the PBP book carried over to Perltidy (!))
# The following Perltidy options are not used, for other reasons:
# -sot, -mft, -cab, -bol, -bok/-nbok, -bot/-nbot, -iob, -isbc

I am free to sputter butt ugly code like this:

   sub  manipulate_some_data{

my $self   =  shift; my $data = shift;
# Sometimes add to the data we received
if($data  eq 'good data'  ){
$data.= ' is now even better.'
;}return $data;}

via my keyboard, and have it instantly transformed to this:

sub manipulate_some_data {

    my $self = shift;
    my $data = shift;

    # Sometimes add to the data we received
    if ( $data eq 'good data' ) {
        $data .= ' is now even better.';
    return $data;

by Perltidy. Without wasting a single of my overworked brain cells.
(I have configured my IDE to run Perltidy every time I save my source file to disk)

(Click here to download the above .perltidyrc file, if your're too lazy for a copy&paste operation)

Perltidy cleans up my code while I develop, which is great, but the true benefit of Perltidy becomes apparent when you or someone else tries to understand your code 4 weeks later: Since all code you and your teammates produce have the same layout, everyone reads code a little faster and get a quicker understanding of what is intended.

This positive effect is particularly evident when fixing a bug or adding some small feature to existing code, because in these situations you typically spend most of your time skimming code, and only a small portion of your time on the few, new lines.

Perl has crossed oceans and climbed mountains to make hard things possible, don't sacrifice this hard-earned property by leaving messy, sloppy, ugly code behind. Clean it up as you go along, by running perltidy from your IDE, and/or as part of your versioning system's commit process.

Free lunches are hard to come by. Perltidy is one of very few I've come across.