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> ML didn’t have single-line comments, so same level of surprising limitation.

It is not quite clear to me why the lack of single-line comments is such a surprising limitation. After all, a single-line block comment can easily serve as a substitute. However, there is no straightforward workaround for the lack of nested block comments.

> I’ve never heard someone refer to C as “expressive”, but maybe it was in 1972 when compared to assembly.

I was thinking of Fortran in this context. For instance, Fortran 77 lacked function pointers and offered a limited set of control flow structures, along with cumbersome support for recursion. I know Fortran, with its native support for multidimensional arrays, excelled in numerical and scientific computing but C quickly became the preferred language for general purpose computing.

While very few today would consider C a pinnacle of expressiveness, when I was learning C, the landscape of mainstream programming languages was much more restricted. In fact, the preface to the first edition of K&R notes the following:

"In our experience, C has proven to be a pleasant, expressive and versatile language for a wide variety of programs."

C, Pascal, etc. stood out as some of the few mainstream programming languages that offered a reasonable level of expressiveness. Of course, Lisp was exceptionally expressive in its own right, but it wasn't always the best fit for certain applications or environments.

> And what bearing does the comment syntax have on the expressiveness of a language?

Nothing at all. I agree. The expressiveness of C comes from its grammar, which the language parser handles. Support for nested comments, in the context of C, is a concern for the lexer, so indeed one does not directly influence the other. However, it is still curious that a language with such a sophisticated grammar and parser could not allocate a bit of its complexity budget to support nested comments in its lexer. This is a trivial matter, I know, but I still couldn't help but wonder about it.






Fair enough. From my perspective, lack of single line comments is a little surprising because most other languages had it at the time (1973, when ML was introduced). Lack of nested comments doesn’t seem surprising, because it isn’t an important feature for a language, and because most other languages did not have it at the time (1972, when C was introduced).

I can imagine both pro and con arguments for supporting nested comments, but regardless of what I think, C certainly could have added support for nested comments at any time, and hasn’t, which suggests that there isn’t sufficient need for it. That might be the entire explanation: not even worth a little complexity.


AFAIK, C didn't get single line comments until C99. They were a C++ feature originally.

Oh wow, I didn’t remember that, and I did start writing C before 99. I stand corrected. I guess that is a little surprising. ;)

Is true that many languages had single line comments? Maybe I’m forgetting more, but I remember everything else having single line comments… asm, basic, shell. I used Pascal in the 80s and apparently forgot it didn’t have line comments either?


That's my recollection, that most languages had single line comments. Some had multi-line comments but C++ is the first I remember having syntaxes for both. That said, I'm not terribly familiar with pre-80s stuff.

> Fortran 77 lacked function pointers

But we did have dummy procedures, which covered one of the important use cases directly, and which could be abused to fake function/subroutine pointers stored in data.




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