I think this particular Julia code is pretty misleading, and I'm (probably) one of the most qualified people in this particular neck of the woods. I wrote a transpiler for Julia that converts a Brainfuck program to a native Julia function at parse time, which you can then call like you would any other julia function.

Here's code I ran, with results:

  julia> using GalaxyBrain, BenchmarkTools

  julia> bench = bf"""
      >++[<+++++++++++++>-]<[[>+>+<<-]>[<+>-]++++++++       
      [>++++++++<-]>.[-]<<>++++++++++[>++++++++++[>++
      ++++++++[>++++++++++[>++++++++++[>++++++++++[>+       
      +++++++++[-]<-]<-]<-]<-]<-]<-]<-]++++++++++."""

  julia> @benchmark $(bench)(; output=devnull, memory_size=100)
  BenchmarkTools.Trial: 
    memory estimate:  352 bytes
    allocs estimate:  3
    --------------
    minimum time:     96.706 ms (0.00% GC)
    median time:      97.633 ms (0.00% GC)
    mean time:        98.347 ms (0.00% GC)
    maximum time:     102.814 ms (0.00% GC)
    --------------
    samples:          51
    evals/sample:     1

  julia> mandel = bf"(not printing for brevity's sake)"

  julia> @benchmark $(mandel)(; output=devnull, memory_size=500)
  BenchmarkTools.Trial: 
    memory estimate:  784 bytes
    allocs estimate:  3
    --------------  
    minimum time:     1.006 s (0.00% GC)
    median time:      1.009 s (0.00% GC)
    mean time:        1.011 s (0.00% GC)
    maximum time:     1.022 s (0.00% GC)  
    --------------
    samples:          5  evals/sample:     1

Note that, conservatively, GalaxyBrain is about 8 times faster than C++ on "bench.b" and 13 times faster than C on "mandel.b," with each being the fastest language for the respective benchmarks. In addition, it allocates almost no memory relative to the other programs, which measure memory usage in MiB.

You could argue that I might see similar speedup for other languages on my machine, assuming I have a spectacularly fast setup, but this person ran their benchmarks on a tenth generation Intel CPU, whereas mine's an eighth generation Intel CPU:

  julia> versioninfo()
    Julia Version 1.5.1
    Commit 697e782ab8 (2020-08-25 20:08 UTC)
    Platform Info:  OS: Linux (x86_64-pc-linux-gnu)
    CPU: Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz  
    WORD_SIZE: 64
    LIBM: libopenlibm  LLVM: libLLVM-9.0.1 (ORCJIT, skylake)

This package is 70 lines of Julia code. You can check it out for yourself here: https://github.com/OTDE/GalaxyBrain.jl

I talk about this package in-depth here: https://medium.com/@otde/six-months-with-julia-parse-time-tr...