This is about how to implement an Idris back end within hours or even minutes.

POSTER PDF: final.pdf in the project root directory.

You're expected to use stack install . to build this project and install it.

This repo provides 3 solid implementations, for Python, Julia, and Ruby.

Check following files in the root directory:

• backend.py

• backend.jl

• backend.rb

We tested the implemented back ends with examples from Idris Offical Tutorials, check examples/testcases.idr.

To build and run the tests, firstly cd into libs directory and idris --install quick-backend.ipkg, then

• build: bash build-tests.sh

  • examples/*.qb will be generated according to examples/*.idr

  • examples/*.py, examples/*.jl and examples/*.rb will be generated according to examples/*.qb

• run: bash run-tests.sh

Runtime System(RTS) provides a set of primitive operations, but according to your use case, you usually don't need to implement all of them.

For instance, running the Ruby file generated by our compiler requires a rts.rb in the same directory, further, in that rts.rb, you should implement a class RTS like this: rts.rb.

Also, the Python, Ruby and Julia editions are available:

• rts.py

• rts.rb

• rts.jl

The full set of primitive operations are listed at Lower.hs#L255.

It seems that their semantics haven't be documented by Idris yet, but according to the data definition in the code, things shall be clarified enough: https://github.com/idris-lang/Idris-dev/blob/master/src/IRTS/Lang.hs#L72

To make an easier use of Idris FFI, we wrapped the Idris FFI Mechanism.

As a result, we get capable of calling foreign functions in this way:

fv "foreign value"
callff0 "foreign function name"
callff1 "foreign function name" (unsafe idris_value)
callff2 "foreign function name" (unsafe idris_value) (unsafe idris_value)
...

This does break the type safety of Idris, but for achieving a quick industrial integration, we provide this.

It's still a future research about support for the full featured Idris FFI, i.e., type safe FFI.

In terms of the current design, when accessing a foreign function or value named foreign, you're actually accessing RTS.foreign in the backend.

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