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I'm in the wg14, and I made a passionate argument against defer. C is all about simplicity and clarity, over conviniance. Defer, is an invisible jump, its much

I'm in the wg14, and I made a passionate argument against defer. C is all about simplicity and clarity, over conviniance. Defer, is an invisible jump, its much better using a goto, that clearly denotes a change in flow. In C everything should be as clear and as explicit as possible. Nothing should happen without the user explicitly saying so. This means more typing, and thats fine, there are plenty of languages that offer loads of syntax sugar if thats what users want, but only C offers clarity.

klodolph 4y ago
I think this is the right approach. You can make C better without trying to compete with newer languages.
- pjmlp 4y ago
  Yeah, why bother competing with newer languages on safety, that was never something that mattered on C's design.
enriquto 4y ago
Thank you so much for your work! Your comment made me happy and warm inside, as if there's still some order in this crazy world. As if there's still a few sane and robust things that we can attach ourselves to, knowing that they will not break. How can we support/encourage you? (in case you need it)
- quelsolaar 4y ago
  Speaking up is a good start! The support is much apprechiated!
secondcoming 4y ago
If C is simple and clear why is it fraught with pitfalls? While C code can be nice and clear to read that doesn’t mean there less mental burden on the developer to keep track of everything going on.
- quelsolaar 4y ago
  I would argue that there is less mental burden, if you stay within some simple limits. C has a lot of complexity if you push its limits, mainly because it is so old and the limits have been pushed in ways they havent in other languages. C has to run on very strange platforms and has many many implementations, and so much code depending on it. This makes it very hard to maintain. If two large C compilers do things slightly different and very important software depends on those behaviours, then its very hard to make a "Clean" fix without breaking lots of software. The argument against "Why dont they just fix X?" usualy commes down to: it would break millions of lines of code, make every C tutorial/book obsolete and force millions of C programmers to learn new things, not to mention that if we broke the ABI, we would break almost every other language since they depend on Cs stable ABI. Breaking C would literaly cost tens if not hundreds of billions of dollars for the industry. Look at the move between Python 2 and 3. The cost of breaking bakwards compatibility have probably been astonomical, and then there is way less Pyton code being maintained then C code. C operates on a scale that is almost unfathomable. A 1% perfomance degredation, in C will have ameasurable impact on the worlds energy use and co2 emissions, so the little things really matter.
  - dmz73 4y ago
    C programmers claim some things that are simply not true: 1) simplicity - C is not a simple language, it is a language lacking advanced features which does not make it simple to use but it might be easier to create incomplete non-performant C compiler than compiler for better languages 2) performance - C naive/straight forward/clear implementations are not the most performant and most of the C programs are not highly optimised for performance, C compilers have had so much optimisation work done on them that they can actually generate decently performant code but if better languages received same level of effort as what C had they would be able to achieve better performance than C with smaller and safer code 3) clarity - C is not clear to read once structs and pointers are used and specially once it is optimised for performance...and then there is the preprocessor...which is a whole different language that is required to make any non-hello-world program even possible If I have to provide examples for any of the above you are either not a C programmer or you are an "advanced" C programmer that doesn't have to deal with large code bases and instead deals with small pieces and someone else takes care of the rest. I mean, just try to figure out what long int is on Linux without compiling a program and tell me that C is simple and clear language...and if you are still clinging on that lie then tell me what a struct looks like in memory so I can interface to it from another language...or even another C compiler...because C is simple and clear, right?
anonymoushn 4y ago
Will promotion of arithmetic results to int be removed, since this is generally a force against simplicity and clarity?
yazaddaruvala 4y ago
> Nothing should happen without the user explicitly saying so. Umm, why is typing something like defer (and documenting what it does) different than typing something like goto (and documenting what it does)? Frankly, not being comfortable with adding safe and efficient abstractions to a language will result in the death of the language (both for spoken languages and also for programming languages).
- naasking 4y ago
  > Umm, why is typing something like defer (and documenting what it does) different than typing something like goto (and documenting what it does)? Because goto is explicitly declaring a control flow where defer causes implicit control flow in code that does not explicity declare it. That's a meaningful difference that the OP was trying to specifically avoid regardless of whether you care about it.
  - yazaddaruvala 4y ago
    Why is "defer" not considered "explicitly declaring control flow" if the documentation describes it correctly?
    - naasking 4y ago
      Because the control flow happens implicitly at the end of the block, not explicitly as with goto, loop, if-statements, etc. A deferred statement can also have arbitrary time and space complexity, so it's not like a variable going out of scope at the end of a block which is constant time. It furthermore requires invocation of all deferred statements while unwinding the stack upon calling exit(). See the details here: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2589.pdf https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2589.pdf
      - yazaddaruvala 4y ago
        > Because the control flow happens implicitly at the end of the block Why is this different than any loop in C? or function without a return? Wouldn’t it be more explicit and very minimal overhead to instead always use a goto at the end of a looping block? Even tho C allows while loops (as a mistake - all control flow should be explicitly defined at the end of the block), why aren’t you - as a best practice - using an explicit goto and if block instead of while / for?
ff317 4y ago
Did you get rid of longjmp() too? longjmp() is far more perilous for similar reasons and purposes. Defer is useful for code clarity in many situations IMHO, and it's easy enough for a project or code QA tool to ban its use for those that don't like it.
- Gibbon1 4y ago
  And think he should push to get rid of terrible things like stdint and designated initializers too.
  - masklinn 4y ago
    Surely <string.h> is the first standard header to execute?
d0mine 4y ago
> simplicity and clarity ... It may be deceptive. Just look at how various compilers or even the same compiler with different options interpret the same C code. > as explicit as possible C is not assembler.

klodolph 4y ago

I think this is the right approach. You can make C better without trying to compete with newer languages.

pjmlp 4y ago
Yeah, why bother competing with newer languages on safety, that was never something that mattered on C's design.

enriquto 4y ago

Thank you so much for your work! Your comment made me happy and warm inside, as if there's still some order in this crazy world. As if there's still a few sane and robust things that we can attach ourselves to, knowing that they will not break. How can we support/encourage you? (in case you need it)

quelsolaar 4y ago
Speaking up is a good start! The support is much apprechiated!

secondcoming 4y ago

If C is simple and clear why is it fraught with pitfalls? While C code can be nice and clear to read that doesn’t mean there less mental burden on the developer to keep track of everything going on.

quelsolaar 4y ago
I would argue that there is less mental burden, if you stay within some simple limits. C has a lot of complexity if you push its limits, mainly because it is so old and the limits have been pushed in ways they havent in other languages. C has to run on very strange platforms and has many many implementations, and so much code depending on it. This makes it very hard to maintain. If two large C compilers do things slightly different and very important software depends on those behaviours, then its very hard to make a "Clean" fix without breaking lots of software. The argument against "Why dont they just fix X?" usualy commes down to: it would break millions of lines of code, make every C tutorial/book obsolete and force millions of C programmers to learn new things, not to mention that if we broke the ABI, we would break almost every other language since they depend on Cs stable ABI. Breaking C would literaly cost tens if not hundreds of billions of dollars for the industry. Look at the move between Python 2 and 3. The cost of breaking bakwards compatibility have probably been astonomical, and then there is way less Pyton code being maintained then C code. C operates on a scale that is almost unfathomable. A 1% perfomance degredation, in C will have ameasurable impact on the worlds energy use and co2 emissions, so the little things really matter.
- dmz73 4y ago
  C programmers claim some things that are simply not true: 1) simplicity - C is not a simple language, it is a language lacking advanced features which does not make it simple to use but it might be easier to create incomplete non-performant C compiler than compiler for better languages 2) performance - C naive/straight forward/clear implementations are not the most performant and most of the C programs are not highly optimised for performance, C compilers have had so much optimisation work done on them that they can actually generate decently performant code but if better languages received same level of effort as what C had they would be able to achieve better performance than C with smaller and safer code 3) clarity - C is not clear to read once structs and pointers are used and specially once it is optimised for performance...and then there is the preprocessor...which is a whole different language that is required to make any non-hello-world program even possible If I have to provide examples for any of the above you are either not a C programmer or you are an "advanced" C programmer that doesn't have to deal with large code bases and instead deals with small pieces and someone else takes care of the rest. I mean, just try to figure out what long int is on Linux without compiling a program and tell me that C is simple and clear language...and if you are still clinging on that lie then tell me what a struct looks like in memory so I can interface to it from another language...or even another C compiler...because C is simple and clear, right?

anonymoushn 4y ago

Will promotion of arithmetic results to int be removed, since this is generally a force against simplicity and clarity?

yazaddaruvala 4y ago

> Nothing should happen without the user explicitly saying so. Umm, why is typing something like defer (and documenting what it does) different than typing something like goto (and documenting what it does)? Frankly, not being comfortable with adding safe and efficient abstractions to a language will result in the death of the language (both for spoken languages and also for programming languages).

naasking 4y ago
> Umm, why is typing something like defer (and documenting what it does) different than typing something like goto (and documenting what it does)? Because goto is explicitly declaring a control flow where defer causes implicit control flow in code that does not explicity declare it. That's a meaningful difference that the OP was trying to specifically avoid regardless of whether you care about it.
- yazaddaruvala 4y ago
  Why is "defer" not considered "explicitly declaring control flow" if the documentation describes it correctly?
  - naasking 4y ago
    Because the control flow happens implicitly at the end of the block, not explicitly as with goto, loop, if-statements, etc. A deferred statement can also have arbitrary time and space complexity, so it's not like a variable going out of scope at the end of a block which is constant time. It furthermore requires invocation of all deferred statements while unwinding the stack upon calling exit(). See the details here: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2589.pdf https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2589.pdf
    - yazaddaruvala 4y ago
      > Because the control flow happens implicitly at the end of the block Why is this different than any loop in C? or function without a return? Wouldn’t it be more explicit and very minimal overhead to instead always use a goto at the end of a looping block? Even tho C allows while loops (as a mistake - all control flow should be explicitly defined at the end of the block), why aren’t you - as a best practice - using an explicit goto and if block instead of while / for?

ff317 4y ago

Did you get rid of longjmp() too? longjmp() is far more perilous for similar reasons and purposes. Defer is useful for code clarity in many situations IMHO, and it's easy enough for a project or code QA tool to ban its use for those that don't like it.

Gibbon1 4y ago
And think he should push to get rid of terrible things like stdint and designated initializers too.
- masklinn 4y ago
  Surely <string.h> is the first standard header to execute?

d0mine 4y ago

> simplicity and clarity ... It may be deceptive. Just look at how various compilers or even the same compiler with different options interpret the same C code. > as explicit as possible C is not assembler.