Category: code

I don't just drink coffee or booze, watch movies and Internet drama, and look cool. I code sometimes, too! Who knew?!

Carrying on with my experiment in Julia, packaging has another step needed to make references. For instance, Ansi uses Geometry, so:

Geometry/Project.toml:

authors = ["Mark Damon Hughes "]
name = "Geometry"
uuid = "e3172796-a620-11e8-2cbf-612649bb77f8"
version = "0.1.0"

[deps]

Ansi/Project.toml:

authors = ["Mark Damon Hughes "]
name = "Ansi"
uuid = "72992c94-a620-11e8-3d05-55611ea0dbd0"
version = "0.1.0"

[deps]

Geometry = "e3172796-a620-11e8-2cbf-612649bb77f8"

Ansi/Manifest.toml:

[[Geometry]]
repo-rev = "master"
repo-url = "/Users/mdh/Code/CodeJulia/Geometry"
uuid = "e3172796-a620-11e8-2cbf-612649bb77f8"
version = "0.1.0"

All the boldface code is what I wrote/copy-pasted, the rest is generated by juliaMakePackage.zsh. I may go ahead and make a tool to link projects, because it's so error-prone. In fact, I cheated, and made a single Manifest.toml which I copy to all projects so far, and can replace whenever something updates.

Anyway, this gets me to a nice state where I can write using Ansi in my project and it'll just find it. IIUC, if I move all the libraries to a public repository, I can just change the repo-url and the packages are downloaded into ~/.julia cache somewhere.

I still haven't followed up on making a binary application; the more I look into that, the jankier it seems, more like something to defer until there's an official solution. Putting a real UI on it is also something to work on, but that's much more doable.

Coding

I've written a lot more code, over 1000 LOC, not just screwing around with packages. Mostly this is enjoyable, it's a nice systems programming language. The ugly parts haven't yet driven me insane, they're just things to work around or ignore. Far less frustrating than almost any other new language; Rusty Nail In Your Head and Go Fuck Yourself Its Google aren't my favorites.

Strong typing really is a pain in the ass. Declare a variable or struct field foo, and it takes anything. Type it with foo::AbstractString, and you soon learn nothing is not a string; foo::Union{AbstractString,Nothing} is necessary to be nullable. Ick.

Enumerations

Enumerated types @enum are disappointing. They're a little smarter than C enums, but not as useful as Java enums. They just represent a value; but you have to cast them to Int every time you use them for their value, so too painful to use them as array indices. Or as characters, a thing I like a lot for debugging. And they're not easy to reflect on:

julia> @enum Terrains begin
               Ter_Floor = Int('.')
               Ter_Wall = Int('#')
       end
julia> Ter_Wall
Ter_Wall::Terrains = 35
julia> Int(Ter_Wall)
35
julia> Char(Int(Ter_Wall))
'#': ASCII/Unicode U+0023 (category Po: Punctuation, other)
julia> String(Char(Int(Ter_Wall)))
ERROR: MethodError: no method matching String(::Char)
julia> string(Char(Int(Ter_Wall)))
"#"
julia> # FFS
julia> string(Ter_Floor)
"Ter_Floor"
julia> # Surprisingly easy!
julia> instances(Terrains)
(Ter_Floor::Terrains = 46, Ter_Wall::Terrains = 35)
julia> # Shit, this is a named tuple, not a dictionary!
julia> useful_instances = Dict()
Dict{Any,Any} with 0 entries
julia> for v in values(instances(Terrains))
           useful_instances[ string(v) ] = v
           useful_instances[ string(Char(Int(v))) ] = v
       end
julia> useful_instances
Dict{Any,Any} with 4 entries:
  "Ter_Floor" => Ter_Floor
  "Ter_Wall"  => Ter_Wall
  "#"         => Ter_Wall
  "."         => Ter_Floor
julia> # JFHC

That was an annoying adventure to get a simple reverse lookup.

So I wanted to move all my common Julia code to a support dir. My filesystem has for 30+ years contained:

$HOME/
    Code/
        CodeC/
            foo/
                src/
                    bar.c
        CodeJava/
            foo/
                src/
                    com/
                        mdh/
                            bar/
                                Quux.java
        et fucking cetera

Build scripts for most languages expect something very like this, and it's easy to import one package's source into another, so I could put common code in a "Marklib" project, and get work done.

Making this happen in Julia was a lot more difficult. With a little help from Slack I made sense of the terrible package documentation for Julia and the incomprehensible errors, and wrote a script juliaMakePackage.zsh:

#!/bin/zsh
if [[ $# -ne 1 ]]; then
    echo "Usage: juliaMakePackage.zsh NAME"
    exit 1
fi
name=$1
devdir=$HOME/Code/CodeJulia
cd $devdir
julia -E "using Pkg; Pkg.activate(\".\"); Pkg.generate(\"${name}\")"
cd $name
git init
git add .
git commit -m "Initial commit"
cd ..
julia -E "using Pkg; Pkg.develop(PackageSpec(url=\"${devdir}/${name}\"))"

And then added the main dir and all packages I make to ~/.julia/config/startup.jl:

# startup.jl

push!(LOAD_PATH, pwd())
push!(LOAD_PATH, "$(homedir())/Code/CodeJulia")
push!(LOAD_PATH, "$(homedir())/Code/CodeJulia/Marklib")

println("READY $(pwd())")

Now finally I can:

% julia
READY /Users/mdh
julia> using Marklib
julia> Marklib.greet()
Hello World!
julia> 

And from there start putting in my libs. Each one needs a package and a startup entry; I may have to automate that by walking my code dir. Waste of several hours figuring that out.

Last time, I was uncertain about string concatenation, so I did a test:

#!/usr/bin/env julia

const kTestText = "abcdefghijklmnopqrstuvwxyz0123456789\n"
const kLoops = 10000

function stringString()
    s = ""
    for i in 1:kLoops
        s = "$s$kTestText"
    end
    return s
end

function bufferString()
    sb = IOBuffer()
    for i in 1:kLoops
        print(sb, kTestText)
    end
    return String(take!(sb))
end

function vectorString()
    sb = Vector()
    for i in 1:kLoops
        push!(sb, kTestText)
    end
    return join(sb, "")
end

function typedVectorString()
    sb = Vector{AbstractString}()
    for i in 1:kLoops
        push!(sb, kTestText)
    end
    return join(sb, "")
end

println("*** stringString")
@timev stringString()
sleep(2)

println("\n*** bufferString")
@timev bufferString()
sleep(2)

println("\n*** vectorString")
@timev vectorString()
sleep(2)

println("\n*** typedVectorString")
@timev typedVectorString()

*** stringString
  1.100197 seconds (21.24 k allocations: 1.725 GiB, 15.94% gc time)
elapsed time (ns): 1100197167
gc time (ns):      175349222
bytes allocated:   1851904041
pool allocs:       11292
non-pool GC allocs:9950
GC pauses:         79

*** bufferString
  0.006864 seconds (11.80 k allocations: 1.134 MiB)
elapsed time (ns): 6864042
bytes allocated:   1189493
pool allocs:       11794
non-pool GC allocs:3
realloc() calls:   8

*** vectorString
  0.017380 seconds (26.68 k allocations: 2.191 MiB)
elapsed time (ns): 17380237
bytes allocated:   2297091
pool allocs:       26659
non-pool GC allocs:9
realloc() calls:   8

*** typedVectorString
  0.031384 seconds (44.75 k allocations: 2.999 MiB, 10.00% gc time)
elapsed time (ns): 31384383
gc time (ns):      3137654
bytes allocated:   3144221
pool allocs:       44730
non-pool GC allocs:8
realloc() calls:   8
GC pauses:         1

Well, there's me told off. I expected #1 typedVector, #2 vector, #3 buffer, then stringString way at the bottom. Instead the first 3 are reversed.

IOBuffer, as ugly as it is, is the clear winner. Vector did OK, but twice as much CPU & RAM loses. Amusing that typedVector is twice as slow and memory-heavy as the untyped (explained ). On larger loops, buffer gets slower, but vector remains a memory pig, and in GC that's unacceptable. Of course stringString is terrible, and it's almost exactly the same for string(s, kTestText).

Time to rewrite some text processing.