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When you refactor you are taking shots at moving around where coupling occurs. If your code is maximally decoupled it is primitive copy-paste code that never ca

When you refactor you are taking shots at moving around where coupling occurs. If your code is maximally decoupled it is primitive copy-paste code that never calls functions and intoduces unique variables for each section - and if it's maximally coupled it will look like swiss cheese, trying to reuse the same functionality for everything with clever parameterization, recursion, indirection and globals. Intentionally coupled code is most common in memory-starved environments since implict dependency helps reduce data overheads. And so "DRY", to the extent that it's useful, encourages you to find slack areas in the code where there's low potential for introducing coupling, and to factor those out so that you have code that is mostly-decoupled without also being redundant and hard to modify - the factoring reflects "knowledge" about the problem. And yet it's not always obvious when you have the knowledge or not. Sometimes redundant-looking code is a form of hardcoded data and a factoring would only push it towards being fully data-driven(which exacts a price in debugging). The Rule of Three is just a common way of making this decision about knowledge.

novembermike 7y ago
The issue is that "DRY" isn't actually about coupling at all, it's about creating unambiguous ways to do things. If you have a single http library that's DRY, but if you've got a function that encapsulates several tangentially related bits of code that's not DRY. The acronym just doesn't say what it means.
temac 7y ago
If your textual copy past includes some requirements of conforming to a contract, or simply actual copy past of "knowledge" (which can very well also be a under the form of a big textual pattern), the mere form of "primitive copy-paste code that never calls functions and intoduces unique variables for each section" does not actually reduces coupling (except MAYBE if it is expanded down to the metal, including expansion of syscall and/or low level libraries, but you won't do that). Also what have globals anything to do with that, and why do you put them in the supposedly factorized code. You are mistaking it with a bad mess you once saw, maybe? On the other hand, code bases obtained through copy paste based programming can not be considered anything else than a bad mess. But yes, factorizing can be done badly, even to the point of being counterproductive. Like anything.

novembermike 7y ago

The issue is that "DRY" isn't actually about coupling at all, it's about creating unambiguous ways to do things. If you have a single http library that's DRY, but if you've got a function that encapsulates several tangentially related bits of code that's not DRY. The acronym just doesn't say what it means.

temac 7y ago

If your textual copy past includes some requirements of conforming to a contract, or simply actual copy past of "knowledge" (which can very well also be a under the form of a big textual pattern), the mere form of "primitive copy-paste code that never calls functions and intoduces unique variables for each section" does not actually reduces coupling (except MAYBE if it is expanded down to the metal, including expansion of syscall and/or low level libraries, but you won't do that). Also what have globals anything to do with that, and why do you put them in the supposedly factorized code. You are mistaking it with a bad mess you once saw, maybe? On the other hand, code bases obtained through copy paste based programming can not be considered anything else than a bad mess. But yes, factorizing can be done badly, even to the point of being counterproductive. Like anything.