# Here I collect some interesting links.

## cargo environment

Currently I always build all dependencies within th projects own .cargo subdir
by setting the environment variable CARGO_HOME.

    export CARGO_HOME=./.cargo

Actually I am quite unsure if that is really a good idea because this results
in a lot of rebuilds for each new project.

## Implement Monads with rust.

Which is currently difficult through impossible, but might be feasible with
some small additions to the rust type system, namely
«(generic) associated traits.»

[Read here](https://varkor.github.io/blog/2019/03/28/idiomatic-monads-in-rust.html)

### Is impl Trait what we needed?

A new language feature which sounded a bit like the needed one for above is:

[impl Trait](https://medium.com/@iopguy/impl-trait-in-rust-explanation-efde0d94946a)

Crossreading it a bit seems to indicate that this is not like the above needed
language feature.

## WASM ... on gentoo ...

Right now rust is not really a first class citizen within the gentoo eco
system. For that reason at least when compiling rust with the `system-llvm`
use flag some manual preparations are needed.

### general informations about Wasm from MDN ...

[WebAssembly](https://developer.mozilla.org/en-US/docs/WebAssembly)

### rustwasm tutorial

[rustwasm](https://rustwasm.github.io/book/introduction.html)

### location of rustlib ...

`wasm-pack` expects the wasm runtime under /usr/lib/rustlib/ but a gentoo
installation puts it under /usr/lib/rust-1.39.0/rustlib/. To come around this
issue I just created a symlink.

Maybe it would be best to send a patch for also settings this symlink to
upstream eselect-rust.

### Missing lld

Again `wasm-pack` searches for llvm-lld or rust-lld for the link phase. This
is currently not a dependency for llvm with WASM support, so I installed it
manually. Finally you have to tell rustc to use lld as linker via this
environment variable:

    export RUSTFLAGS="-C linker=lld"

## Traits when, how & why

A slightly old but still worthwhile post about rusts standard traits.

[About traits](https://llogiq.github.io/2015/07/30/traits.html)

# Side note... 3d math
[3d math primer](https://www.3dgep.com/3d-math-primer-for-game-programmers-vector-operations/)
[basic 3d math](https://matrix44.net/cms/notes/opengl-3d-graphics/basic-3d-math-vectors/)
[vector calculator](https://www.mathportal.org/calculators/matrices-calculators/vector-calculator.php)
[3d vector mathematics](https://vvvv.org/documentation/3d-vector-mathematics)
[sin appr. with fractions](https://dsp.stackexchange.com/questions/46629/finding-polynomial-approximations-of-a-sine-wave)

# transformations within a coordinate system.
[migenius](https://www.migenius.com/articles/3d-transformations-part1-matrices)
[tutorialspoint](https://www.tutorialspoint.com/computer_graphics/3d_transformation.htm)

# more math...

A whole lot of interesting stuff about continued fractions:
[continues fractions](http://www.maths.surrey.ac.uk/hosted-sites/R.Knott/Fibonacci/cfINTRO.html)