From: Joel Pearson <lists@...>
Date: 2013-03-10T00:31:00+09:00
Subject: Re: RubyExcel class. Useful?

Thanks for your input, Robert.

I did wonder whether I should convert the underlying dataset into an 
Array rather than using a Hash, since spreadsheets are "structured" and 
I find the easiest way to manipulate the structure is with Array 
methods. Enumerable seems to be Array-based as well, and I'm still 
rather hazy on when to override methods like "map", or when to rely on 
the methods already available through "each".
Still, I've learned a lot about Hashes while writing this code, so even 
if I do abandon their use for the main data storage I'll still find good 
use for them elsewhere.

My reasoning behind the prevalence of headers is simply that if you 
wanted data without headers you'd just use arrays rather than this 
class. One of the big things I find helpful with this is that code is 
much more readable if I can reference a header rather than an index.
I'm not sure what a test class or wrapper class is. I'll look them up.

I see your point about to_s. I suppose I should differentiate between 
using interpolation for multiple variables and to_s for single cases.

The +, -, and << methods are recent additions; mostly because I only 
just learned that you can define these. I'm sure there are multiple ways 
to write these; my first attempt was very poor in performance... and my 
thinking was to avoid re-inventing the wheel by using the Array methods 
written by someone much smarter than me :)

I hadn't realised that I was evaluating "empty?" twice in "[]=". That 
was a performance-increasing experiment I'd tried to avoid recalculating 
the dimensions after every write operation. It made quite a difference 
at the time and I hadn't looked into simplifying it yet.

All in all, this still needs a lot of work to make it useful; but now 
that I have a better feel of what the weaknesses and strengths are, I 
hope to improve on this starting point and eventually build something 
genuinely useful to others as well as myself.

I'd be particularly interested on the question of Array vs Hash for the 
internals. Hash is great because of the simplicity of addresses and its 
efficient way of coping with blank space, but Arrays can keep their 
"form" much more effectively and already support things like sorting, 
rows, and columns.

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