Rich kids are into COBOL

Peter Corlett abuse at
Sat Feb 28 05:35:06 CST 2015

On Fri, Feb 27, 2015 at 04:48:07PM -0800, Chuck Guzis wrote:
> APL certainly encouraged thinking about things in a different way. I wonder
> what today would look like if APL was used as a "first language" to teach
> programming.

It's a special-purpose language for mathematical manipulation. As such, it's
not actually a very good choice for a first language.

When I was a wee nipper, everybody's first language was BASIC because that's
what came with the machine. These days, it's more likely to be Java or perhaps
Python. Python's the better of the two and supports similar manipulations to
APL. For example, Python forms of the examples in are:

>>> n = [4, 5, 6, 7]
>>> n
[4, 5, 6, 7]
>>> map(lambda x: x+4, n)
[8, 9, 10, 11]
>>> sum(n)
>>> m = sum([i + 3 for i in range(1,5)]); m

And in Scala, which runs on the JVM and thus interoperates with Java:

scala> val n = Vector(4, 5, 6, 7)
n: scala.collection.immutable.Vector[Int] = Vector(4, 5, 6, 7)

scala> n
res0: scala.collection.immutable.Vector[Int] = Vector(4, 5, 6, 7)

scala> n map (_+3)
res1: scala.collection.immutable.Vector[Int] = Vector(7, 8, 9, 10)

scala> n.sum
res2: Int = 22

scala> val m = 1 to 4 map (_ + 3) sum; m
warning: there was one feature warning; re-run with -feature for details
m: Int = 22
res3: Int = 22

The "feature warning" is that I used postfix "sum", which is an ambiguous parse
in some cases. It wants me to write it as the uglier (1 to 4).map(_ + 3).sum

Functional programming idioms have crept into many OO and imperative languages
to give them APL-like power. APL's cryptic syntax is not a feature; if you want
that, you know where to find Perl or Clojure.

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