4 ms·

What's wrong with CMake?

by skohan 6y ago

bluGill 6y ago
The syntax is weird and inconsistent. Built ins are case insensitive, but user defined functions are sensitive. No way to return values from functions, except by jumping to the scope of the caller and changing its variables unexpectedly. (Better hope you know what the caller does) That isn't a complete list . Despite the above cmake is your best choice of build system for C. Though some competitors could overtake it.
- andi999 6y ago
  On top of that I found the documentation and the book terrible. I thought it might be easier to understand what it does by reading the source code (didn't try yet)
  - ahartmetz 6y ago
    The documentation is "complete" in the way that some manpages are - the biggest problem with it is the lack of best practices guidance. About books, I believe that good ones exist now. The official CMake book is not among the good ones - last time I checked, it was ridiculously outdated (and IMO not even very good at the time it was written). I have extracted some knowledge from the source code. It's more underdesigned than overdesigned and I think that's the better side to err on. Kinda awkward but you can figure it out.
    - andi999 6y ago
      Which cmake book is good?
      - bluGill 6y ago
        Professional cmake seems to be the one recommended now. The author updates it regularly.
- jmagoon 6y ago
  My least favorite part is how completely impossible it is to discover all the implicit variables set by other cmake files, and there's no common convention, so some libraries are like ${ZLIB_INCLUDE_DIR} and some are #{zLib_INCLUDE_DIRS} and you have to just manually try a bunch of combinations to finally find what works because the scripts themselves use weird string based metaprogramming to build the variables themselves.
- appleflaxen 6y ago
  which competitors? any thoughts on why are build tools so hard to get right?
  - bluGill 6y ago
    Build2 is one that a coworker of mine likes. There are others. What makes it hard is the problem is a lot deeper than most people realize, so most attempts are not powerful enough to be useful. They are clean until someone points out one of the many edge cases that were not thought of, and by the time you support even a few of them your clean design is a mess of uglyness. Making it worse build systems are an afterthought to most develpers so you end up with a mess just because the programers are not taking care to write good clean code in the build system.
IshKebab 6y ago
The language is extremely error prone. It's like they looked at Bash and thought "hmm, too safe". Everything is a string, even lists are just semicolon-separated lists. The argument expansions rules for calling functions are literally impossible to remember. All variables are implicitly defined as empty strings. Typos silently break things. `if` is completely broken. The separation of the configure step from the build step is needlessly confusing and makes some things impossible. This is just scratching the surface. It does have a couple of redeeming qualities: they have a pretty great versioning mechanism which allows them to make breaking changes. Though inexplicably they haven't used it to fix any fundamental flaws, only little tweaks. And most importantly it has been around for ages so loads of the many many weird C++ compilation knobs have been solved.
- dev_tty01 6y ago
  > It's like they looked at Bash and thought "hmm, too safe". One of my favorite comments in a while. :-)
- cycloptic 6y ago
  >The separation of the configure step from the build step is needlessly confusing and makes some things impossible. I'm confused. How do you propose CMake supports all those build generators without doing this? (PS. I really don't think the syntax is that bad, aside that it is jarring for C programmers, most complaints are overblown and you get used to it once you learn the rules. It might be interesting if someone made a CMake variant with a less obscure syntax but I don't see much motivation for that to actually happen)
  - kevin_thibedeau 6y ago
    The syntax has improved slightly in recent releases with the target family of commands. You just have to know what legacy parts to avoid which is itself a burden. Still it beats digging into the bowels of autotools. I do fantasize about a new Cmake frontend implemented with Tcl scripting. That would be far more consistent and flexible and you can disable much of the language by default to minimize footbullets then allow commands to be reenabled for times they're needed.

What's wrong with CMake?

by skohan 6y ago

What's wrong with CMake?

The syntax is weird and inconsistent. Built ins are case insensitive, but user defined functions are sensitive. No way to return values from functions, except by jumping to the scope of the caller and changing its variables unexpectedly. (Better hope you know what the caller does) That isn't a complete list . Despite the above cmake is your best choice of build system for C. Though some competitors could overtake it.

andi999 6y ago
On top of that I found the documentation and the book terrible. I thought it might be easier to understand what it does by reading the source code (didn't try yet)
- ahartmetz 6y ago
  The documentation is "complete" in the way that some manpages are - the biggest problem with it is the lack of best practices guidance. About books, I believe that good ones exist now. The official CMake book is not among the good ones - last time I checked, it was ridiculously outdated (and IMO not even very good at the time it was written). I have extracted some knowledge from the source code. It's more underdesigned than overdesigned and I think that's the better side to err on. Kinda awkward but you can figure it out.
  - andi999 6y ago
    Which cmake book is good?
    - bluGill 6y ago
      Professional cmake seems to be the one recommended now. The author updates it regularly.
jmagoon 6y ago
My least favorite part is how completely impossible it is to discover all the implicit variables set by other cmake files, and there's no common convention, so some libraries are like ${ZLIB_INCLUDE_DIR} and some are #{zLib_INCLUDE_DIRS} and you have to just manually try a bunch of combinations to finally find what works because the scripts themselves use weird string based metaprogramming to build the variables themselves.
appleflaxen 6y ago
which competitors? any thoughts on why are build tools so hard to get right?
- bluGill 6y ago
  Build2 is one that a coworker of mine likes. There are others. What makes it hard is the problem is a lot deeper than most people realize, so most attempts are not powerful enough to be useful. They are clean until someone points out one of the many edge cases that were not thought of, and by the time you support even a few of them your clean design is a mess of uglyness. Making it worse build systems are an afterthought to most develpers so you end up with a mess just because the programers are not taking care to write good clean code in the build system.

IshKebab 6y ago

The language is extremely error prone. It's like they looked at Bash and thought "hmm, too safe". Everything is a string, even lists are just semicolon-separated lists. The argument expansions rules for calling functions are literally impossible to remember. All variables are implicitly defined as empty strings. Typos silently break things. `if` is completely broken. The separation of the configure step from the build step is needlessly confusing and makes some things impossible. This is just scratching the surface. It does have a couple of redeeming qualities: they have a pretty great versioning mechanism which allows them to make breaking changes. Though inexplicably they haven't used it to fix any fundamental flaws, only little tweaks. And most importantly it has been around for ages so loads of the many many weird C++ compilation knobs have been solved.

dev_tty01 6y ago
> It's like they looked at Bash and thought "hmm, too safe". One of my favorite comments in a while. :-)
cycloptic 6y ago
>The separation of the configure step from the build step is needlessly confusing and makes some things impossible. I'm confused. How do you propose CMake supports all those build generators without doing this? (PS. I really don't think the syntax is that bad, aside that it is jarring for C programmers, most complaints are overblown and you get used to it once you learn the rules. It might be interesting if someone made a CMake variant with a less obscure syntax but I don't see much motivation for that to actually happen)
- kevin_thibedeau 6y ago
  The syntax has improved slightly in recent releases with the target family of commands. You just have to know what legacy parts to avoid which is itself a burden. Still it beats digging into the bowels of autotools. I do fantasize about a new Cmake frontend implemented with Tcl scripting. That would be far more consistent and flexible and you can disable much of the language by default to minimize footbullets then allow commands to be reenabled for times they're needed.