Functional programming generally involves a lot of dynamic memory allocations (which are usually optimized in some way). Without some form of assisted memory management, this quickly becomes excruciating. C also lacks function closures, so important abstractions like function composition, partial application and higher order functions. It also lacks type parameterization and polymorphism.
Not everyone will consider all of these to be fundamental to functional programming, but I'm certain most people would require at least one. C simply doesn't provide powerful enough mechanisms for abstraction to enable any interesting parts of functional programming.
C++, Rust, D and Nim all do, however. If one ever felt the need to use them in a functional matter it would be possible, albeit unpleasant.
>Functional programming generally involves a lot of dynamic memory allocations (which are usually optimized in some way)
It's symptomatic of many functional languages, but it's not a prerequisite.
> . C also lacks function closures, so important abstractions like function composition, partial application and higher order functions.
That, on the other hand, is a core feature of functional languages (what does it mean to have functions as first class citizens if one cannot manipulate them in an algebraic way?). I actually think it's the only needed feature to qualify.
> It also lacks type parameterization and polymorphism.
These are strongly typed languages features, I wouldn't define a functional language by it (I don't think it's necessary), although it appears in many of them.
If I get the point of the article, the author would argue that cpp provides some form of closure (you can code a macro that generates a function that behaves somewhat like a closure if you want...)
Not everyone will consider all of these to be fundamental to functional programming, but I'm certain most people would require at least one. C simply doesn't provide powerful enough mechanisms for abstraction to enable any interesting parts of functional programming.
C++, Rust, D and Nim all do, however. If one ever felt the need to use them in a functional matter it would be possible, albeit unpleasant.
Additional reading: https://news.ycombinator.com/item?id=8609775