Greppability is an underrated code metric

Re:Greppability is an underrated code metric by kragen on Tuesday September 03, 2024 @08:00AM (#41434069)

c's macro system is weak on purpose, based on, i suspect, bad experiences with m6 and m4. i think they thought it was easier to debug things like ratfor, tmg, lex, and (much later) protoc, which generate code in a more imperative paradigm for which their existing debugging approaches worked

i can't say i think they were wholly wrong; paging through compiler error messages is not my favorite part of c++ templates. but i have a certain amount of affection for what used to be called gasp, the gas macro system, which i've programmed for example to compute jump offsets for compiling a custom bytecode. and i think m4 is really a pathological case; most hairy macro systems aren't even 10% as bad as m4, due to a combination of several tempting but wrong design decisions. lots of trauma resulted

so when they got a do-over they eliminated the preprocessor entirely in golang, and compensated with reflection, which makes debugging easier rather than harder

probably old hat to you, but i just learned last month how to use x-macros in the c preprocessor to automatically generate serialization and deserialization code for record types (speaking of cobol): http://canonical.org/~kragen/sw/dev3/binmsg_cpp.c

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Re:Greppability is an underrated code metric by skissane on Tuesday September 03, 2024 @08:05AM (#41434108)

C's is weak yet not weak – you can do various advanced things (like conditional expansion or iteration), but using esoteric voodoo with extreme performance cost. Whereas other preprocessors let you do that using builtins which are fast and easy to grok.

See for example https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,...

Poor C preprocessor performance has a negative real world impact, for example recently with the Linux kernel – https://lwn.net/Articles/983965/ – a more powerful preprocessor would enable people to do those things they are doing anyway much more cheaply

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Re:Greppability is an underrated code metric by lanstin on Tuesday September 03, 2024 @12:43PM (#41436671)

I've always suspected the powerful macro facilities in Lisp are why it's never been very common - the ability to do proper macros means all the very smart programmers create code that has to be read like a maths paper. It's too bespoke to the problem domain and too tempting to make it short rather than understandable.

I like Rust (tho I have not yet programmed in it) but I think if people get too into macro generated code, there is a risk there to its uptake.

It's hard for smart programmers to really believe this, but the old "if you write your code as cleverly as possible, you will not be able to debug it" is a useful warning.

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