Saturday, 18 June 2011

gets gets my goat

I'm participating in a virtual study group on the book Seven languages in seven weeks. The first week has been on Ruby, which has been a liberating and and frictionless experience - except for one glitch.

One of the exercises in the book involves writing a primitive grep in Ruby. This program reads text line-by-line from stdin and echos the lines that contain a fragment specified as a command-line argument.

My first attempt looked something like this:
while line = gets
    puts line if line.match ARGV[0]
But when I tried to run it...
> ./grep.rb foo
./grep.rb:3:in `gets': No such file or directory - foo (Errno::ENOENT)
 from ./grep.rb:3
After a lot of head-scratching, I finally figured out that gets behaves differently if there are command-line arguments. From the Ruby documentation on gets:
Returns (and assigns to $_) the next line from the list of files in ARGV (or $*), or from standard input if no files are present on the command line.
So, I actually needed to do this:
while line = STDIN.gets
    puts line if line.match ARGV[0]
After becoming a little frustrated at this seemingly inexplicable overloading of gets, I took a moment to think about why it bothered me so much.

One benefit that Ruby advocates often cite about the language is its adherence to the Principle of Least Surprise. So in the case of this particular unpleasant surprise, I felt cheated.

But then I realised that the strength of my reaction was a backhanded compliment to Ruby. The gets incident stuck in my mind only because it contrasts so strongly with the rest of my experience of Ruby as a consistent and well-designed programming language.

Saturday, 11 June 2011

Agile teams need the same skills

There is occasionally anxiety about how project managers, business analysts, QAs and other traditional roles fit into agile projects. A project manager new to agile development might feel that their skills and experience aren't valued because they don't see their old job title explicitly mentioned in a description of an agile team.

Agile schedules still need to be managed. Agile requirements still need to be analysed. Agile codebases still need to be tested. The difference is that agile teams don't assume that these activities have to be done by dedicated team members.

A cross-functional team needs a wide variety of skills to succeed. Sometimes these will be provided by specialists and sometimes by generalists. The balance has to be struck for the specific needs of a project and can't be determined by a crude, one-fits-all rule.

Though agile is a great step forward in software development, it would be arrogant and unfair to think that there is no place in agile teams for software professionals that happen to come from traditionally structured organisations.