> those who default to writing every program procedurally and those who default to doing so declaratively.
> those who default to writing every program procedurally and those who default to doing so declaratively.
I would say that imperative is the one that does computation in steps so that one can at each step decide what to do next. Declarative normally lacks this step-like quality. There are non-languages that consist solely of steps (e.g. macros in some tools that allow to record a sequence of steps), but while this is indeed imperative, this is not programming.
One side cares more about how the solution is implemented. They put a lot of focus on the stuff inside functions: this happens, then that happens, then the next thing happens.
The other side cares more about the outside of functions. The function declarations themselves. The types they invoke and how they relate to one another. The way data flows between parts of the program, and the constraints at each of those phases.
Obviously a program must contain both. Some languages only let you do so much in the type system and everything else needs to be done procedurally. Some languages let you encode so much into the structure of the program that by the time you go to write the implementations they’re trivial.
-- my attempt:
Imperative defines the order and semantics of each step.
Declarative defines the prerequisites and intent of each step.
The algorithms each can implement are equivalent.
https://existentialtype.wordpress.com/2013/07/18/what-if-any...
Semantic is another word that is hard to define.
I find imperative better for expressing state machines. I find declarative better for backtracking.
You can write a state machine with just a loop, an assignable, and conditions. Writing state in prolog is irritating.
Similarly declarative programming is strictly secondary to imperative. It is a limited form of imperative that codifies some good patterns and turns them into a structure. But it also makes it hard or impossible not to use these patterns.