Functional Reactive Programming (FRP) is a specific programming model with a specific semantics.
(Actually, there are two variants, which are sometimes called “classic FRP” and “arrow FRP”.)
I’ve given a summary in an answer to “What is (functional) reactive programming?”.
As I said there, the two key properties for me have always been (a) precise & simple denotation and (b) continuous time.
I regret that this model came to be called “functional reactive programming”, for a few reasons:
- That name omits “time”, and time is central for me.
- The term “functional” has so little specific/clear meaning.
I much prefer Peter Landin’s suggested replacement “denotative”.
(See the quotes and reference in this blog comment.) - It’s easy for people to incorrectly think they know what the term means because they know meanings (more or less) of each of the three words.
For descriptiveness & accuracy, I prefer the term “denotative continuous-time programming” (suggested by Jake McArthur in a conversation a while back) over “functional reactive programming”.
I wrote a very short piece on the origin of FRP in the blog post Early inspirations and new directions in functional reactive programming.