Comments on: Coding: Copy/Paste then refactor http://www.markhneedham.com/blog/2009/10/31/coding-copypaste-then-refactor/ Thoughts on Software Development Tue, 16 Mar 2010 05:27:04 +0000 http://wordpress.org/?v=2.8.4 hourly 1 By: Carlo http://www.markhneedham.com/blog/2009/10/31/coding-copypaste-then-refactor/comment-page-1/#comment-26123 Carlo Tue, 03 Nov 2009 08:05:00 +0000 http://www.markhneedham.com/blog/?p=1777#comment-26123 Typically I find when working with collections that everything has been done already and I like to use the mechanisms there where possible. They may not be the most efficient but often easy to understand. I know you're learning Scala and one of the best ways is trying to do things manually so you learn the idioms etc. Anyway after looking at the code you ended up with it reminded me of a sorted collection and a parameterised sort closure. So in Smalltalk (sorry I haven't learned Scala yet, but Groovy would look similar) it would be something like: |min max| min := aCollectionHoldingInts asSortedCollection first. max := aCollectionHoldingInts asSortedCollection last. Or we could do (although slower), max := aCollectionHoldingInts asSortedCollection reversed last. Alternatively if you're not storing int's in the collection but rather an object then you sould pass the sort block around: max := aCollection asSortedCollection: [:a :b | a someIntField > b someIntField]. Cheers Carlo Typically I find when working with collections that everything has been done already and I like to use the mechanisms there where possible. They may not be the most efficient but often easy to understand. I know you're learning Scala and one of the best ways is trying to do things manually so you learn the idioms etc.

Anyway after looking at the code you ended up with it reminded me of a sorted collection and a parameterised sort closure.
So in Smalltalk (sorry I haven't learned Scala yet, but Groovy would look similar) it would be something like:

|min max|
min := aCollectionHoldingInts asSortedCollection first.

max := aCollectionHoldingInts asSortedCollection last.
Or we could do (although slower),
max := aCollectionHoldingInts asSortedCollection reversed last.

Alternatively if you're not storing int's in the collection but rather an object then you sould pass the sort block around:
max := aCollection asSortedCollection: [:a :b | a someIntField > b someIntField].

Cheers
Carlo

]]> By: Book Club: Working Effectively With Legacy Code – Chapter 8 (Michael Feathers) at Mark Needham http://www.markhneedham.com/blog/2009/10/31/coding-copypaste-then-refactor/comment-page-1/#comment-26066 Book Club: Working Effectively With Legacy Code – Chapter 8 (Michael Feathers) at Mark Needham Mon, 02 Nov 2009 14:17:34 +0000 http://www.markhneedham.com/blog/?p=1777#comment-26066 [...] the section on TDD Feathers mentions the copy/paste/refactor pattern which I wrote about a few days ago. Cam pointed out that this technique allows us to get to the [...] [...] the section on TDD Feathers mentions the copy/paste/refactor pattern which I wrote about a few days ago. Cam pointed out that this technique allows us to get to the [...]

]]> By: Josh Ribakoff http://www.markhneedham.com/blog/2009/10/31/coding-copypaste-then-refactor/comment-page-1/#comment-26062 Josh Ribakoff Mon, 02 Nov 2009 13:27:25 +0000 http://www.markhneedham.com/blog/?p=1777#comment-26062 Oh yeah, and I started to notice recently sometimes the 3rd function that is born ends up becoming a public method and a core part of the system's API. Maybe not in this case but take for example a method extraction in the middle of a loop, now you have a method to call when you have an object instead of a collection Oh yeah, and I started to notice recently sometimes the 3rd function that is born ends up becoming a public method and a core part of the system's API. Maybe not in this case but take for example a method extraction in the middle of a loop, now you have a method to call when you have an object instead of a collection

]]> By: Josh Ribakoff http://www.markhneedham.com/blog/2009/10/31/coding-copypaste-then-refactor/comment-page-1/#comment-26061 Josh Ribakoff Mon, 02 Nov 2009 13:24:32 +0000 http://www.markhneedham.com/blog/?p=1777#comment-26061 Kent Beck uses this method as his introduction to TDD, he had me sold right away. Kent Beck uses this method as his introduction to TDD, he had me sold right away.

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