Make it possible to add interpreters with Metatheory.jl

[sebdumancic]

https://juliasymbolics.github.io/Metatheory.jl/dev/tutorials/while_interpreter/

MetaTheory.jl would make it possible to add any interpreter painlessly!

[ReubenJ]

Super cool!

Just a note of caution here, the execution time seems orders of magnitude slower than our current default interpret function. I'm not certain these comparisons are fair—I did my best to match them to the example at the beginning of the tutorial. It might be that I'm not understanding the correct use of the package.

Comparing times:

julia> [round(median(res.times)) for res in [res_raw, res_meta, res_int]]
3-element Vector{Float64}:
   24.0
 3776.0
   89.0

Code to reproduce

"Raw" version:

some_mem = Dict(:x => 2)
f = (m, v) -> m[v]
res_raw = @benchmark f(some_mem, :x)

MetaTheory.jl version:

Mem = Dict{Symbol,Union{Bool,Int}}
read_mem = @theory v σ begin
  (v::Symbol, σ::Mem) => σ[v]
end

σ₁ = Mem(:x => 2)
program = :(x, $σ₁)
res_meta =  @benchmark rewrite(program, read_mem)

HerbInterpret.jl version:

some_mem = Dict(:x => 2)
tab = Dict(
    :get => get,
    :missing => missing,
    :some_mem => some_mem,
    :f => f,
    :x => x,
)
res_int = @benchmark interpret(tab, :(f(some_mem, x)))

Package versions used

Status `Project.toml`
  [6e4b80f9] BenchmarkTools v1.4.0
  [5bbddadd] HerbInterpret v0.1.1
  [e9d8d322] Metatheory v2.0.2

[sebdumancic]

that is a good catch!
Indeed, I don't think the package intends to be very performant, only to make it easy to write a custom interpreter.

but, we should keep it in mind and see whether we want to make use of it or not.