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What is this sorcery? #include <datatype99.h> datatype( BinaryTree, (Leaf, int), (Node, struct BinaryTree *, i

What is this sorcery? #include <datatype99.h> datatype( BinaryTree, (Leaf, int), (Node, struct BinaryTree *, int, struct BinaryTree *) ); What kind of preprocessor black magic can you do so that this code compiles? I don't dare to open the file datatype99.h lest it casts a dark spell on me.

willxinc 6y ago
https://github.com/Hirrolot/epilepsy https://github.com/Hirrolot/epilepsy According to the GitHub, which appears to be a metaprogramming library by the same author.
flohofwoe 6y ago
The whole system seems to be built on top of variadic macros (which had been standardized in C99).
Hirrolot 6y ago
Yes, as others have already noticed, it is implemented on top of https://github.com/Hirrolot/epilepsy https://github.com/Hirrolot/epilepsy, a metalanguage for preprocessor metaprogramming.
- jrimbault 6y ago
  > a metalanguage for preprocessor metaprogramming That sentence is everything I was taught to avoid. Props to you. I like the drug/alcohol metaphor for these things, as a child avoid them, as an adult do your thing as long as you remain sensible.
  - globuous 6y ago
    Funny you use this example, the author's GH page says he's 16; in many countries he wouldn't be able to drink, event responsibly ^^
    - masklinn 6y ago
      > in many countries he wouldn't be able to drink But in most countries they would be able to drink (especially in a private setting), just not purchase. In Europe for instance less than half a dozen countries have a minimum drinking age for private settings, and a dozen more have an MDA in public (but not private), though for some 16 is enough to drink fermented alcohols (alongside a meal with adults for the UK, regardless for Germany and Austria).
- enriquto 6y ago
  LOL, I cannot get enough of this shit! Can you point to some cool implementation tricks that you used to achieve that? I guess there's quite a bit of ## concatenation to create temporary names and stuff?
  - Hirrolot 6y ago
    Well, mostly I use idioms from the Cloak Wiki (https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,-tips,-and-idioms https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,...). It takes some time to realise them :)
- orra 6y ago
  In case anybody mistakenly thinks doing so is 'cheating', you're the author of both libraries! This is absurd, but in a good way.

willxinc 6y ago

https://github.com/Hirrolot/epilepsy https://github.com/Hirrolot/epilepsy According to the GitHub, which appears to be a metaprogramming library by the same author.

flohofwoe 6y ago

The whole system seems to be built on top of variadic macros (which had been standardized in C99).

Hirrolot 6y ago

Yes, as others have already noticed, it is implemented on top of https://github.com/Hirrolot/epilepsy https://github.com/Hirrolot/epilepsy, a metalanguage for preprocessor metaprogramming.

jrimbault 6y ago
> a metalanguage for preprocessor metaprogramming That sentence is everything I was taught to avoid. Props to you. I like the drug/alcohol metaphor for these things, as a child avoid them, as an adult do your thing as long as you remain sensible.
- globuous 6y ago
  Funny you use this example, the author's GH page says he's 16; in many countries he wouldn't be able to drink, event responsibly ^^
  - masklinn 6y ago
    > in many countries he wouldn't be able to drink But in most countries they would be able to drink (especially in a private setting), just not purchase. In Europe for instance less than half a dozen countries have a minimum drinking age for private settings, and a dozen more have an MDA in public (but not private), though for some 16 is enough to drink fermented alcohols (alongside a meal with adults for the UK, regardless for Germany and Austria).
enriquto 6y ago
LOL, I cannot get enough of this shit! Can you point to some cool implementation tricks that you used to achieve that? I guess there's quite a bit of ## concatenation to create temporary names and stuff?
- Hirrolot 6y ago
  Well, mostly I use idioms from the Cloak Wiki (https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,-tips,-and-idioms https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,...). It takes some time to realise them :)
orra 6y ago
In case anybody mistakenly thinks doing so is 'cheating', you're the author of both libraries! This is absurd, but in a good way.