Allow compilation parameters as array and fold sizes

[ivanlele]

Project

compiler

Describe the feature

Array lengths and fold/array_fold sizes should also accept compilation parameters in addition to literals.

This would let contracts configure compile-time structure sizes, such as Sparse Merkle Tree depth, multisig key count, proof batch size, or validation rounds, without changing the source.

let values: [u32; param::SIZE] = ...;
fold::<step, param::SIZE>(...);
array_fold::<step, param::SIZE>(...);

[apoelstra]

Neat! This will complicate quoting but ultimately it's totally compatible.

If you took the quote of such an expression, it would take param::SIZE as an input value, and depending on its size, produce different CMRs. To implement this we'd have to design "quoted versions" of the existing list/array builtins.