ex_ecc

This is an Elixir language port of the python library py_ecc from the Ethereum project.

It's a file-to-file port so to make it easier to compare the code and understand the differences as well as to incorporate new changes.

Same goes for the tests.

Port notes

• Original python files are in py_ecc/ and tests/ the new ported files are in lib/ and test/ correspondingly.

• Type enforcement is generally not ported.

• Elixir does not have class inheritance but py_ecc field maths is heavily based on that. So to keep the port mostly source similiar there is an Elixir specific FieldMath module that handles inheritance. And because super is an Elixir keyword with a different meaning instead all uses of python super instead use the elixir function parent

• Initializers and constructors are created using a single def new(fp \\ %__MODULE{}, arg1, arg2)using a default argument to be both used as init and new.

• While loops are ported using the While compat module:

import While

# to keep source similarity
{i, j} = while {i, j}, i < 10 do
    {i + 1, j - 1}
end

# and sometimes the nicer function variant
i = reduce_while(1, fn i ->
    if i < 10 do
        {:cont, i + 1}
    else
        {:halt, i}
    end
end)

• If/elif/else statements are replaced with cond do

cond do
    len(low) != 3 -> 3
    len(low) != 2  -> 2
    true -> raise "Invalid low argument"
end

• Pythonic expressions like [0] * x become: List.duplicate([0], x)

• Unused module attributes are covered with getters such as def b(), do: @b to avoid warnings.