Although it's perhaps not as important early on as Henry's excellent
advice, I would like to advocate for good use of whitespace and grouping
in J programming. Putting less space around parts which are evaluated
first (generally adverbs) and more around those which are evaluated last
makes it a lot easier to interpret the code and mentally group its parts
together. So I would write (hoping for no line wrap)
isAnagramOf =: 0: ` ([: */ =&([: /:~@tolower ' '&i. # ])) @. (=&([: # ' '&i. #
]))
Here I have replaced a few (@) constructions with ([:), as ([: u v) is
equivalent to (u@:v) but frequently requires fewer distracting
parentheses. Many programmers prefer (@:) instead, but it is a good idea
to use (@:) unless there is an actual reason to use (@). I would
probably further replace ([: # ' '&i. # ]) with (' '&i. #@:# ]), and
subsequently realize that dyad (#@:#) is the same as (+/@:[), giving
(' '&i. +/@:[ ]) or (' ' +/@:i. ]), and similarly group (*/) with (=) as
(*/@:=), since this becomes an easily-understood idiom.
The two concrete points here are:
- Use whitespace to show precedence: tighter spacing around operators
with less precedence.
- Replace ([: u v@:w) with ([: u@:v w) when u and v are related. This
holds for (&:) instead of (@:), and in monad and dyad forms.
And the more general rule: pay attention to how your code is written! It
can suggest a lot of relationships that help the reader (usually you) to
understand what is happening.
Marshall
On Sun, Mar 13, 2016 at 03:21:15PM +0000, Adam Tornhill wrote:
> Hi all,
> I finally decided to try to understand this fascinating language. So far I've
> spent some evenings reading and experimenting with the language. J is fun.
> Real fun. I also like how J forces me to re-consider how I view programming.
> Of course, that also means I'm still at a complete beginner's stage, so I'd
> like to ask for some feedback and suggestions on my first J code. I'm sure
> there's a lot I can simplify in my code.
> Here's the code I put together by digging around in the J Dictionary:
> isAnagramOf=:(0:`((*/)@(=&((/:~@tolower)@(' ' & i.#])))))@.(=&(#@:(' ' &
> i.#])))
>
> Some examples:
> 'Nag a Ram ' isAnagramOf 'Anagram'1
> 'ab' isAnagramOf 'aa'0
> All tips and hints on both the code and learning J in general would be much
> welcome.
> Thanks!/Adam-- Homepage: www.adamtornhill.com Twitter: @AdamTornhill
> Your Code as a Crime Scene:
> https://pragprog.com/book/atcrime/your-code-as-a-crime-sceneLisp for the Web:
> https://leanpub.com/lispwebPatterns in C: https://leanpub.com/patternsinc
> ----------------------------------------------------------------------
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