Specifying Function Contract

[ChrisRackauckas]

@nsajko

To expand, the way that Symbolics implements == breaks the contract of the == function, which is one of the more important functions.

The contract of == explicitly does not necessarily return a boolean and there is a separate function in Julia if you want to guarantee a boolean, and that’s isequal.

@nsajko

The approach that Symbolics.jl took may allow it to be useful as a CAS, but prevents it from integrating into the Julia ecosystem well.

It does this so that it integrates with the Julia ecosystem because it keeps the contracts of the language and uses isequals vs == appropriately. If it did not do this, then it would not work with general functions. This is how come tracing of numerical functions works.