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Back in October I started my latest programming project. Not some game or utility or mobile app. This project was to learn a bunch of different programming languages all at the same time. After writing the mandatory ďHello WorldsĒ I set about my first real task. Something simple, something easy...

What could be easier than getting a computer to do some arithmetic? After all, itís what those ones and zeros are best at. Two and a half long months later and Iíve discovered just now easy this task really wasnít.

I set eight CS 101-style problems revolving around arithmetic but they also included peripheral skills like user input, functions, recursion, iteration, etc. All stuff that I can rattle through in no time at all with a few Googles: ďIf statement in SmalltalkĒ and the like should give me the answers I need quick enough. Well, except that there is no ďifĒ in Smalltalk; no sane representation of Strings in Erlang; and the uses of ďreturnĒ and ďechoĒ in BASH functions were so alien to my Java mindset, I had to ask a colleague for help!

Itís not all doom and gloom though. I was able to rattle through a lot of the languages and those that did trip me up were the ones I learned the most. Here were my eight tasks:

  • Add two numbers entered by the user.
  • Fizz Buzz.
  • Implement the smart power algorithm.
  • Calculate Fibonacci numbers recursively.
  • Calculate Fibonacci numbers iteratively.
  • Use Newtonís method to solve an equation.
  • Print a vertical sine wave out of asterisks.
  • A function to calculate the digital root of a numbers.


Ruby and Python were both easy. Iíd say that Ruby was more fun to write in but Python looks easier to read and maintain. Haskell was fairly straightforward too but I googled a lot and asked for some advice on here. Of course, an iterative solution isnít possible in Haskell but you can define the sequence using zipWith which is much faster than the usual recursive definition:

 module Main
	where
	fib = 1 : 1 : zipWith (+) fib (tail fib)
	main = putStrLn (show (take 50 fib)) 


I thought Erlang might be a simple be a case of changing the syntax of the Haskell programs I had already written. It was, to an extent, but the syntax I was finding with Google made less and less sense to me as I went along. In the end, I paused and read the first few chapters of learn you some Erlang for great good! Itís an excellent introduction to the language and explains some alien [to me] concepts in a very accessible way. After rewriting my Erlang solutions without looking at my Haskell ones, I came out pretty happy with the syntax.

C, C# and Javascript were up next. They were all pretty straightforward. C surprised me by making me declare loop counters before the loop. This turned out to be a really interesting issue. It turns out that the C standards have had both as an option since 1999, along with things like variable length arrays. However, compiler support for the C99 standard is abysmal across the board.

// In Java I might do this:
for(int i = 0; i < 10; i++)

// C wants this:
int i;
for(i = 0; i < 10; i++)


BASH had me pulling my hair out. I gave up on Google and online tutorials, and got a friend to sit down and show me how it was done. Part of the problem was the numbskull idea of trying to learn BASH by getting it to do maths. It is designed to automate tasks and do a bit of text processing. Earlier versions didnít even have the capability to do maths. Even now, it is limited to integer maths invoked with a special syntax. For floating point calculations, you have to invoke another utility (often bc).

Then there were echo and return. I would have expected echo to write to the console and return to pass a value back from a function, and those assumptions were often correct, ďoftenĒ being the operative word. Rather than passing back a value, return passes back an exit code: 0 for success and anything else for a failure. It took me the longest time to realise why all my calculations were coming out as zero.

Echo prints to the console, or rather stdout. So, when used in a function, the value goes back to the caller a bit like piping. In other words this is the return I was looking for. Actually, Iím not sure Iím 100% happy with this explanation. I think there is something important Iím missing here. Something to look out for on the next iteration!

Smalltalk went a lot better. I had no idea where to start though, and wasnít sure Squeak was the implementation I wanted. The IDE had nowhere obvious to start writing code and the whole thing looked a bit childish. I reached for a tutorial and started working my way through it.

It turns out that the whole thing is a live Smalltalk program. The browser uses the reflective qualities of the language to navigate the classes and methods. You can change anything on the fly, and roll back when you break things. Methods tend to be small and unit testing is built in.

There is not much in the way of control structures. Instead of an if statement, you create a Boolean object (usually from a condition) and send an ifTrue: or ifFalse: message. Loops are similar. Itís all whileTrue: on Boolean closures or internal iterators on lists. Itís a nice way to program but I didnít believe there is no conditional logic somewhere in the language. The beauty of Smalltalk is that I can go and check. I dug out the Boolean class and found the ifTrue: method was abstract. The two subclasses (True and False) have rather obvious implementations. An instance of True evaluates the block of code you pass it, False does nothing. Looks like the flow control is down to the evaluation of Boolean expressions and is handled by the interpreter.

ĒA line out of my recursive Fibonacci method.Ē
(n = 1 or: n = 2) ifTrue: [^1].


Far from my initial impressions of the language, Iím very impressed with Squeak, and look forward to using it for a project one day. My main reservation is deployment. I still need to look into it but I think anyone who wants to run my programs has to run them from Squeak.

Finally, I did my assignments in Lua. It was perfectly straightforward, a refreshing change.

This exercise turned out to be less to do with maths and more to do with getting to grips with the fundamentals of the languages. I think Iím in more of a position to sit down and be able to write something in each of the languages here. At least Iíd know where to look for help. Iíve had a tour round all the languagesí documentations and a flick through several tutorials.

Although Iíve learned a lot, ten weeks is too long for iterations. Itís been ten weeks since Iíve looked at Ruby. To put it in perspective, the teaching part of a semester at my university is 12 weeks! Itís too long. Iím going to look at some String handling next but Iím going to set a smaller task, maybe one or two programs in each language. I hope to be back sooner with a blog article proclaiming my success!

Thanks for reading!

2 Comments On This Entry

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xclite Icon

29 December 2011 - 10:50 AM
I've also found BASH to be obnoxious. Whitespace significance and ridiculous syntax rules make it quite difficult to deal with at times. I've decided to just stick to knowing a scripting language and using BASH only as required (almost never).
1

cfoley Icon

29 December 2011 - 05:10 PM
Glad I'm not the only one. :)

BASH is on there because I've used Linux in the past with only a smattering of ability on the command line. I really felt like I was missing out, as demonstrated both by reading online and from people at work showing me tricks of the trade. I guess I'm not really that curious about the language itself but I want the power it gives me over the computer.
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