Back in June it was announced that the next Perl release would be called Perl 7. A quick look back at Perl's history reveals that this is a little unusual. Perl 5 was originally released in October 17, 1994 and served its users well for a number of years. In 2000 Perl 6 was announced as a ground-up redesign of the language and it spent a long time in development. It eventually surfaced in 2015 but in 2019 was renamed "Raku" to distinguish it from traditional Perl. This leaves Perl 6 as a sort of "orphaned" version number.

In the meantime while Raku née Perl 6 was being developed, the team behind Perl 5 had delivery numerous point releases and retained an active community of loyal users. Many of these had no desire to migrate to Raku and wanted a number of quality of life improvements in their language, ecosystem and libraries. The sort of changes being proposed were bigger than you'd expect from a point release, so a new major version was required. Hence Perl 7 - the real next version of Perl.

So we now have quite an interesting situation, let's take a look at the release history:

Over the years many commercial and open source projects have skipped version numbers leaving their own little version holes with their own various explanations. Today we'll take a look at a number of similar situations like this, and we'll try to understand what happened in each case and why.

A fairly typical Perl program which calculates π

PHP 6

Perl was not the first language to skip a version, in fact it wasn't even the first scripting language beginning with "P" to skip version 6. A quick glance at PHP's release history reveals the following:

So what's the story here? Well in common with most software written in the early '00s PHP did not have particularly good Unicode support. The developers behind PHP recognised this and planned a rewrite - PHP 6 - that used Unicode to represent strings internally, specifically UTF-16. Work began in 2005 and would continue for a few years. While some of the planned PHP 6 features were completed on schedule, the Unicode rewrite stalled and became a major blocker to the release. In the meantime Unicode did indeed begin to take off ...

... however UTF-16 didn't. UTF-8, a different standard, rapidly emerged as the preferred Unicode standard on the web. This was particularly problematic since it became apparent that PHP 6 had some serious performance issues dealing with converting strings to and from UTF-8, and since web applications were PHP's bread and butter this was a big deal. In 2010, five years into the PHP 6's development the project was abandoned. Much of the non-Unicode features of PHP6 were ported into PHP 5 and released in version 5.4.

In 2014 as a new major release of PHP was being planned the topic of what it should be called was raised and it was decided that for the sake of removing any confusion or ambiguity the next version of PHP would be PHP 7. There are plenty of justifications given, but the first one given in the RFC I linked really seals it

First and foremost, PHP 6 already existed and it was something completely different. The decimal system (or more accurately the infinite supply of numbers we have) makes it easy for us to skip a version, with plenty more left for future versions to come.

This makes plenty of sense - PHP 6 was already a thing, and it's not like integers are a finite resource. If this was Ubuntu and they were considering discarding a good adjective/animal pair then perhaps it'd be slightly different

ECMAScript 4

Brendan Eich developed Javascript over the course of 10 short days at Netscape, and it soon became the defacto scripting language for the web. This status was confirmed by Ecma who issued a number of standards and referred to it as "ECMAScript". Nowadays they release these standards on a yearly basis (the latest being ECMAScript 2020, published June 2020) but at the end of 2009 we had five ... kinda:

You seem to be repeating falsehoods in blogs since the Proposed ECMAScript 4th Edition Language Overview was published, claiming dissenters including Microsoft were ignored by me, or “shouted down” by the majority, in the ECMAScript standardization group
...
These ES3.1 proposals came suddenly in March after years of passive participation by Microsoft, while the rest of the group worked on ES4. They have not been touched since April.

Watcom 5.0 and earlier

Slackware 5 and 6

For some reason Slackware was the first ever Linux distro I used. I have no idea why I chose it, but looking back it would've been better if I had a more user-friendly one like RedHat or SuSE. Using software on Slackware often involved compiling it yourself, which usually meant hunting down, downloading and compiling dependencies (possibly even encountering more dependencies which require you to hunt down, download and compile sub-dependencies (possibly even encountering more dependencies ... etc)). Between May and October in 1999 they jumped from using 4.0 to 7.0

Conclusion

I only scratched the surface of this subject, really. If look around then you'll start to see missing versions everywhere. For example, what happened to Windows 9? How about .NET [Core] 4, MySQL 6 and 7 or Akumulátor 2? As soon as you apply an sequential version to some software you make a statement about how that software relates to any previous or future releases - whether or not you adhere to a strict set of rules like semver. This is meant to help users and it largely works as intended but does not really give any strong prescription for how to handle abandoned releases or forked-then-remerged projects. As a consequence we have to be cool with the idea that skipping a version or two is perhaps preferable than introducing confusion or even discarding any notion of sequence whatsoever - imagine wondering if it's safe to upgrade from PHP e1daa19 to PHP caf3c64.

I keep encountering things when setting up Jupyter! After I got it running under IIS I went to bed then picked it up the next evening, tried to install the C# and F# kernels from dotnet try. Of course I hit two snags:

Issue 1. C# and F# Kernels aren't available at all

I installed it as usual by opening up Windows Terminal, source-ing my venv, installing dotnet-try globally and installing the dotnet try kernel. I suspected I was gonna encounter something a little odd - I wasn't sure if the dotnet try would respect the venv when I installed jupyter. Turns out the kernel got installed in a weird location (under AppData/Roaming rather than in my venv dir). I did a bit of experimenting and this was how I ended up resolving the issue. First I updated the PATH so that it included both the venv directory and the dotnet tools directory:

    <aspNetCore processPath="python.exe" 
                arguments="launch.py"
                stdoutLogEnabled="true" 
                stdoutLogFile="logs\stdout">
      <environmentVariables>
        <environmentVariable name="PYTHONPATH" value="." />
        <environmentVariable name="PATH" value="%PATH%;C:\Users\sean\.dotnet\tools;.\venv\Scripts" />
      </environmentVariables>    
    </aspNetCore>

Then I opened the terminal and ran the kernel install steps once more:

Once that was in place I could create a new notebook and run F# code:

Issue 2. Notebooks weren't saving

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    <handlers>
      <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
      <remove name="WebDAV" />
    </handlers>

    <modules>
      <remove name="WebDAVModule" />
    </modules>
    
    <aspNetCore processPath=".\venv\Scripts\python.exe" 
                arguments="launch.py"
                stdoutLogEnabled="true" 
                stdoutLogFile="logs\stdout">
      <environmentVariables>
        <environmentVariable name="PYTHONPATH" value="." />
        <environmentVariable name="PATH" value="%PATH%;C:\Users\sean\.dotnet\tools;.\venv\Scripts" />
      </environmentVariables>    
    </aspNetCore>
  </system.webServer>
</configuration>

I use Jupyter Notebooks quite a lot for personal development, and to do this I set up an instance on a DigitalOcean droplet. However I also wanted to do something similar for some tasks at work which can access resources only available in our internal network. Since we use Windows that means I need to do something a little different. I could just use Anaconda to install and load it, but I find it a little clunky, I don't like how it tries to manage everything for you, I wanted a slightly nicer url than https://localhost:8000 and more importantly I wanted it to just be there without having to start anything up. So I set out to get Jupyter Notebook running on IIS using the ASP.NET Core Module V2 on http://notebook.local.

Make sure Python, IIS and the ASP.NET Core Hosting Bundle are installed. Open up a Terminal (I'm using bash, Powershell is probably file but I don't like it), create an new directory where our notebook application will be served, setup a venv there, and run the activation script, upgrade pip so that it doesn't complain at us and then finally install Jupyter Notebook:

$ cd ~/source/repos
$ mkdir notebook
$ python -m venv venv
$ source venv/Scripts/activate
$ pip install --upgrade pip
$ pip install notebook

$ jupyter notebook
[I 20:39:42.322 NotebookApp] The port 8888 is already in use, trying another port.
[I 20:39:42.328 NotebookApp] Serving notebooks from local directory: C:\Users\sean\source\external
[I 20:39:42.329 NotebookApp] Jupyter Notebook 6.1.4 is running at:
[I 20:39:42.329 NotebookApp] http://localhost:8889/?token=e27aa8d7754e1bb078dfdf48e7c55032ac3551360389fd65
[I 20:39:42.329 NotebookApp]  or http://127.0.0.1:8889/?token=e27aa8d7754e1bb078dfdf48e7c55032ac3551360389fd65
[I 20:39:42.329 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 20:39:42.476 NotebookApp]

    To access the notebook, open this file in a browser:
        file:///C:/Users/sean/AppData/Roaming/jupyter/runtime/nbserver-260-open.html
    Or copy and paste one of these URLs:
        http://localhost:8889/?token=e27aa8d7754e1bb078dfdf48e7c55032ac3551360389fd65
     or http://127.0.0.1:8889/?token=e27aa8d7754e1bb078dfdf48e7c55032ac3551360389fd65

So here you can see why I'm doing all this - http://localhost:8888 isn't quite as nice as https://notebook.local. Next let's create a logs folder where our stdout logging will live and notebooks folder where we'll keep our notebook files.

$ mkdir logs notebooks

Next we'll create a Python script called launch.py that will launch Jupyter:

import os, sys
from IPython.terminal.ipapp import launch_new_instance
from IPython.lib import passwd
import warnings

# set the password you want to use
notebook_password = "test"

sys.argv.append("notebook")
sys.argv.append("--IPKernelApp.pylab='inline'")
sys.argv.append("--NotebookApp.ip='*'")
sys.argv.append("--NotebookApp.port=" + os.environ["ASPNETCORE_PORT"])
sys.argv.append("--NotebookApp.open_browser=False")
sys.argv.append("--NotebookApp.notebook_dir=./notebooks")
sys.argv.append("--NotebookApp.password=" + passwd(notebook_password))

launch_new_instance()

This script is kind of interesting, but we'll go into it later once we've got everything up and running. Next we will need to create a Web.config file that'll be used by IIS and ANCMV2 to call this script with the Python executable and libraries from our venv. So let's create the following:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.webServer>
    <handlers>
      <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
    </handlers>
    <aspNetCore processPath=".\venv\Scripts\python.exe" 
                arguments="launch.py"
                stdoutLogEnabled="true" 
                stdoutLogFile="logs\stdout">
      <environmentVariables>
        <environmentVariable name="PYTHONPATH" value="." />
      </environmentVariables>    
    </aspNetCore>
  </system.webServer>
</configuration>

Next we'll set up the new Site in IIS - so open up IIS Manager (hit Start and start typing "Internet Information Services" - it'll appear in the suggestions) then:

1. in the left-hand menu right click the top-level node, hit "Add Website..."
2. in the dialog that appears call the site whatever you like
   
3. in the "Physical Path" section click the "..." button, and choose the directory your notebooks live in
4. in the "Binding" section type "notebook.local" in the "Host name" section

127.0.0.1    notebook.local

So now we have a Website bound to "notebook.local" running under IIS, which is configured to use ASP.NET Core Runtime Module V2 to launch a Python script that will run Jupyter Notebook. Let's fire up a browser and navigate to http://notebook.local and enter the password test:

It loads nicely so let's just create a simple Python 3 notebook to confirm everything works end-to-end:

Excellent. Ok so let's rewind a little bit and ask the question: why do we use a special script instead of having our Web.config file launch jupyter notebook directly? Well that would be ideal, but a bit of a hack required. Notice in launch.py that we grab the ASPNETCORE_PORT environment variable and use that as our port? Well that contains the port IIS wants to communicate with our app in - so we need to hook Jupyter up to listen on that port. While it is possible to call jupyter notebook --port 8080 to specify the port we want to use, it's actually not possible to use the ASPNETCORE_PORT variable in our Web.config. These environment variables are not expanded in our arguments="..." attribute, (see issue #117 in the aspnet/AspNetCoreModule repo on GitHub) - so we need to run a script that grabs this from the Environment and sets it up. It's a bit hacky, but it gets us where we need to be.

# enable US and CZ layouts, toggle with right-win, other possible grp:* values are...
#    grp:alt_caps_toggle         Alt+Caps Lock
#    grp:alt_space_toggle        Alt+Space
#    grp:menu_toggle             Menu
#    grp:lwin_toggle             Left Win
#    grp:win_space_toggle        Win+Space
#    grp:rwin_toggle             Right Win
setxkbmap -layout us,cz                 
setxkbmap -option                       
setxkbmap -option "grp:rwin_toggle"

However I noticed that periodically this would stop working, I'd be stuck on the US layout and my right-windows key would do nothing. Re-running the three setxkbmap commands would fix things up. 

This eventually annoyed me and I resolved to figure it out. Apparently Linux has some power-management module that will cause some USB devices to disconnect, and when they reconnect they appear as a different device without these keyboard settings.

Unsuprisingly my bodge was responsible for this. The correct solution here was to set my XKBLAYOUT to "uz,cz" and to add "grp:rwin_toggle" to my XKBOPTIONS in /etc/default/keyboard:

$ cat /etc/default/keyboard 
# KEYBOARD CONFIGURATION FILE

# Consult the keyboard(5) manual page.

XKBMODEL="pc105"
XKBLAYOUT="us,cz"
XKBVARIANT=""
XKBOPTIONS="lv3:ralt_switch,terminate:ctrl_alt_bksp,grp:rwin_toggle"

BACKSPACE="guess"

Now my layout switching works a little better and my keyboard no longer has bouts of amnesia. That BACKSPACE="guess" line sure does look odd though, I'll need to come back to that at some point.

* = I have no need for the "pound" symbol anymore and US-layout keyboards are much more available

An article titled "This Is What Peak Hello World Looks Like" did the rounds on Hacker News (discussion here), where someone took the plain old printf("hello, world!"); in C and transformed it step-by-step beyond recognition. This was a noble effort, but today I discovered an easier way to make Hello World more insane in a slightly different way:

    $ dotnet new console -o hello -lang F#
    The template "Console Application" was created successfully.

    Processing post-creation actions...
    Running 'dotnet restore' on hello/hello.fsproj...
      Restore completed in 209.4 ms for /home/sean/dev/dotnet/hello/hello.fsproj.

    Restore succeeded.
    
    $ cd hello
    $ cat Program.fs 
    // Learn more about F# at http://fsharp.org

    open System
    
    [<EntryPoint>]
    let main argv =
        printfn "Hello World from F#!"
        0 // return an integer exit code

That's it, an absolute monster of a program. But wait, "This is just a plain old Hello World in .NET! What's so insane about that?" I hear you ask. Well we're not quite done yet, let's get ready to share the executable with our colleague who wants to use our app so we'll add <PublishSingleFile>true</PublishSingleFile> to hello.fsproj - which will generate a single self-contained executable binary - and publish it:

    $ dotnet publish -r linux-x64 -c Release
    Microsoft (R) Build Engine version 16.5.0+d4cbfca49 for .NET Core
    Copyright (C) Microsoft Corporation. All rights reserved.

      Restore completed in 5.27 sec for /home/sean/dev/dotnet/hello/hello.fsproj.
      hello -> /home/sean/dev/dotnet/hello/bin/Release/netcoreapp3.1/linux-x64/hello.dll
      hello -> /home/sean/dev/dotnet/hello/bin/Release/netcoreapp3.1/linux-x64/publish/
    $ ./bin/Release/netcoreapp3.1/linux-x64/publish/hello
    Hello World from F#!
    $ ls -lh ./bin/Release/netcoreapp3.1/linux-x64/publish/hello
-rwxr-xr-x 1 sean sean 78M May 17 22:47 ./bin/Release/netcoreapp3.1/linux-x64/publish/hello

There she blows! An absolute monster - a 78MB Hello World executable! This is actually a bit unfair, since it includes some stuff we might not need, so let's add <PublishTrimmed>true</PublishTrimmed> to hello.fsproj and rebuild:

    $ dotnet publish -r linux-x64 -c Release
    Microsoft (R) Build Engine version 16.5.0+d4cbfca49 for .NET Core
    Copyright (C) Microsoft Corporation. All rights reserved.
    
      Restore completed in 33.8 ms for /home/sean/dev/dotnet/hello/hello.fsproj.
      hello -> /home/sean/dev/dotnet/hello/bin/Release/netcoreapp3.1/linux-x64/hello.dll
      Optimizing assemblies for size, which may change the behavior of the app. Be sure to test after publishing. See: https://aka.ms/dotnet-illink
      hello -> /home/sean/dev/dotnet/hello/bin/Release/netcoreapp3.1/linux-x64/publish/
    $ ./bin/Release/netcoreapp3.1/linux-x64/publish/hello
    Hello World from F#!
    $ ls -lh ./bin/Release/netcoreapp3.1/linux-x64/publish/hello
-rwxr-xr-x 1 sean sean 46M May 17 22:51 ./bin/Release/netcoreapp3.1/linux-x64/publish/hello

Ok, slightly better but that's still a hefty 46MB for Hello World. This is a bit disingenuous however - what's happening is that I've configured the project to be able to produce a self-contained executable, to do this the .NET Core runtime is bundled in the hello binary. So it's a little bit like distributing a little bit of application [byte]code, a bytecode interpreter, a JIT compiler and runtime libraries.

Since .NET Try supports F# officially I wanted to switch over my Jupyter notebook instance to use that instead of IFsharp. But I ran into a couple of frustrating issues that I wanted to document in case anyone else hit them and didn't know how to debug the issue.

Issue 1. dotnet-try installs but isn't usable

I followed Scott Hanselman's instructions to install dotnet-try, but when I tried to execute dotnet try jupyter install it seemed as though dotnet-try wasn't installed at all:

$ dotnet tool install dotnet-try --global
You can invoke the tool using the following command: dotnet-try
Tool 'dotnet-try' (version '1.0.19553.4') was successfully installed.

$ dotnet try jupyter install
Could not execute because the specified command or file was not found.
Possible reasons for this include:
  * You misspelled a built-in dotnet command.
  * You intended to execute a .NET Core program, but dotnet-try does not exist.
  * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.

After a lot of head scratching I dug into the actual docs and learned that both .NET Core 3.0 and .NET Core 2.1 SDKs should be installed, while I only had .NET Core 3.1's SDK So after a quick sudo apt install dotnet-sdk-3.0 dotnet-sdk-2.1 I was successfully able to install the kernel and list it:

$ jupyter kernelspec list
Available kernels:
  .net-csharp    /home/notebook/.local/share/jupyter/kernels/.net-csharp
  .net-fsharp    /home/notebook/.local/share/jupyter/kernels/.net-fsharp
  mit-scheme     /usr/local/share/jupyter/kernels/mit-scheme
  python3        /usr/local/share/jupyter/kernels/python3

Issue 2. Jupyter can't run dotnet-try

However even though it was installed, each time I tried to create a new F# notebook Jupyter would give an error saying that it was unable to connect to the kernel. After taking a quick look at my logs I saw the same error as before!

Feb 09 13:19:11 aviemore jupyter[837]: [I 13:19:11.169 NotebookApp] KernelRestarter: restarting kernel (1/5), new random ports
Feb 09 13:19:11 aviemore jupyter[837]: Could not execute because the specified command or file was not found.
Feb 09 13:19:11 aviemore jupyter[837]: Possible reasons for this include:
Feb 09 13:19:11 aviemore jupyter[837]: * You misspelled a built-in dotnet command.
Feb 09 13:19:11 aviemore jupyter[837]: * You intended to execute a .NET Core program, but dotnet-try does not exist.
Feb 09 13:19:11 aviemore jupyter[837]: * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.
Feb 09 13:19:14 aviemore jupyter[837]: [I 13:19:14.180 NotebookApp] KernelRestarter: restarting kernel (2/5), new random ports
Feb 09 13:19:14 aviemore jupyter[837]: Could not execute because the specified command or file was not found.
Feb 09 13:19:14 aviemore jupyter[837]: Possible reasons for this include:
Feb 09 13:19:14 aviemore jupyter[837]: * You misspelled a built-in dotnet command.
Feb 09 13:19:14 aviemore jupyter[837]: * You intended to execute a .NET Core program, but dotnet-try does not exist.
Feb 09 13:19:14 aviemore jupyter[837]: * You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH. 

EnvironmentFile=/home/jupyter/config/notebook-config

When reading about a Unix command or C library function it's relatively common to see it suffixed with a number in brackets. This is to make it clear what exactly you're talking about, so if someone is discussing mknod they might write mknod(1) they're talking about the shell command or mknod(2) if they mean the syscall. The number used refers to the manpage section, so to see the manpage for the shell function:

$ man 1 mknod

And to see what the syscall is all about:

$ man 2 mknod

According the man manpage on my system there are eight standard manpage sections in total, with one non-standard section:

1. Executable programs or shell commands
2. System calls (functions provided by the kernel)
3. Library calls (functions within program libraries)
4. Special files (usually found in /dev)
5. File formats and conventions eg /etc/passwd
6. Games
7. Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
8. System administration commands (usually only for root)
9. Kernel routines [Non standard]
   

import os
import re
from collections import defaultdict

manpage_gz_pattern = "(.*)\.\w+.gz"
manpage_dir_base = "/usr/share/man"
manpage_sections = range(1, 9)
manpage_entries = defaultdict(list)

for manpage_section in manpage_sections:
    manpage_section_dir = os.path.join(manpage_dir_base, f"man{str(manpage_section)}")
    manpage_section_contents = os.listdir(manpage_section_dir)

    for manpage_entry_filename in manpage_section_contents:
        gz_entry = re.match(manpage_gz_pattern, manpage_entry_filename)
        manpage_entry = gz_entry.groups()[0] 
        manpage_entries[manpage_entry] += [(manpage_section, manpage_entry_filename)]

for section_count in manpage_sections:
    number_of_manpages = len([ m for m in manpage_entries if len(manpage_entries[m]) == section_count])
    print(f"number of manpages in {section_count} sections: {number_of_manpages}")

$ python -i mancount.py
number of manpages in 1 sections: 10763
number of manpages in 2 sections: 107
number of manpages in 3 sections: 7
number of manpages in 4 sections: 0
number of manpages in 5 sections: 0
number of manpages in 6 sections: 0
number of manpages in 7 sections: 0
number of manpages in 8 sections: 1

• mdoc (mdoc.1.gz, mdoc.5.gz, mdoc.7.gz)
• locale (locale.1.gz, locale.5.gz, locale.7.gz)
• hostname (hostname.1.gz, hostname.5.gz, hostname.7.gz)
• passwd (passwd.1ssl.gz, passwd.1.gz, passwd.5.gz)
• time (time.2.gz, time.3am.gz, time.7.gz)
• readdir (readdir.2.gz, readdir.3am.gz, readdir.3.gz)
• random (random.3.gz, random.4.gz, random.7.gz)
  

$ man 1ssl passwd
$ man 1 passwd

I used to think that each time I opened a manpage I learn something completely new and unexpected - but I never thought I'd find something interesting just by looking at the manpages' gzipped filenames!

> let foo x = x;;
val foo : x:'a -> 'a

> let foo x y = (x,y);;
val foo : x:'a -> y:'b -> 'a * 'b

> let foo x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 x11 x12 x13 x14 x15 x16 x17 x18 x19 x20 x21 x22 x23 x24 x25 x26 x27 x28 x29 x30 x31 x32 x33 x34 x35 x36 x37 x38 x39 = (x0,x1,x2,x- 3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16,x17,x18,x19,x20,x21,x22,x23,x24,x25,x26,x27,x28,x29,x30,x31,x32,x33,x34,x35,x36,x37,x38,x39);;
val foo :
  x0:'a ->
    x1:'b ->
      x2:'c ->
        x3:'d ->
          x4:'e ->
            x5:'f ->
              x6:'g ->
                x7:'h ->
                  x8:'i ->
                    x9:'j ->
                      x10:'k ->
                        x11:'l ->
                          x12:'m ->
                            x13:'n ->
                              x14:'o ->
                                x15:'p ->
                                  x16:'q ->
                                    x17:'r ->
                                      x18:'s ->
                                        x19:'t ->
                                          x20:'a1 ->
                                            x21:'a2 ->
                                              x22:'a3 ->
                                                x23:'a4 ->
                                                  x24:'a5 ->
                                                    x25:'a6 ->
                                                      x26:'a7 ->
                                                        x27:'a8 ->
                                                          x28:'a9 ->
                                                            x29:'a10 ->
                                                              x30:'a11 ->
                                                                x31:'a12 ->
                                                                  x32:'a13 ->
                                                                    x33:'a14 ->
                                                                      x34:'a15 ->
                                                                        x35:'a16 ->
                                                                          x36:'a17 ->
                                                                            x37:'a18 ->
                                                                              x38:'a19 ->
                                                                                x39:'a20 ->
                                                                                  'a *
                                                                                  'b *
                                                                                  'c *
                                                                                  'd *
                                                                                  'e *
                                                                                  'f *
                                                                                  'g *
                                                                                  'h *
                                                                                  'i *
                                                                                  'j *
                                                                                  'k *
                                                                                  'l *
                                                                                  'm *
                                                                                  'n *
                                                                                  'o *
                                                                                  'p *
                                                                                  'q *
                                                                                  'r *
                                                                                  's *
                                                                                  't *
                                                                                  'a1 *
                                                                                  'a2 *
                                                                                  'a3 *
                                                                                  'a4 *
                                                                                  'a5 *
                                                                                  'a6 *
                                                                                  'a7 *
                                                                                  'a8 *
                                                                                  'a9 *
                                                                                  'a10 *
                                                                                  'a11 *
                                                                                  'a12 *
                                                                                  'a13 *
                                                                                  'a14 *
                                                                                  'a15 *
                                                                                  'a16 *
                                                                                  'a17 *
                                                                                  'a18 *
                                                                                  'a19 *
                                                                                  'a20

Warning: line too long, ignoring some characters
- 

Minor sidebar - I was going to just say we hit a restriction where 4096 bytes is the max line length, but obviously 1 character isn't necessarily 1 byte if we're using some Unicode representation, and a nice way to check that we're using Unicode is to punch in identifiers that would definitely be in different encodings in an ASCII representation - I used Georgian and Czech characters:

> let სამი = 3;;
val სამი : int = 3

> let čtyři = 4;;
val čtyři : int = 4

> სამი + čtyři;;
val it : int = 7

When I changed my program to start each parameter with the Georgian character "ა" (i.e. let bar ა0 ა1... etc) which cannot be represented in a single byte in UTF-8 we hit the error after only 162 parameters. So it's not a character limit, but a buffer of bytes that we filled - and the size of the buffer is ... uh 4096 bytes.

  x1328,
  ^^^^^

/home/sean/stdin(6636,1): error FS0039: The value or constructor 'x1328' is not defined. Maybe you want one of the following:
   x132
   x138
   x1238
   x128
   x1321

sean@seoul ~/d/s/xmms-1.2.11> ./configure
checking build system type... x86_64-unknown-linux-gnu

MANY LINES LATER

*** The glib-config script installed by GLIB could not be found
*** If GLIB was installed in PREFIX, make sure PREFIX/bin is in
*** your path, or set the GLIB_CONFIG environment variable to the
*** full path to glib-config.
configure: error: *** GLIB >= 1.2.2 not installed - please install first ***

$ git clone https://github.com/smcl/gtk-1.x
$ cd gtk-1.x
$ ./configure --prefix=/usr && make
$ sudo make install

$ git clone https://github.com/smcl/glib-1.x
$ cd glib-1.x
$ ./configure --prefix=/usr && make
$ sudo make install

$ curl -LO http://www.xmms.org/files/1.2.x/xmms-1.2.11.tar.gz
$ tar -xzf xmms-1.2.11.tar.gz
$ cd xmms-1.2.11
$ ./configure && make
$ sudo make install

Then if all is well then the original (and best!) xmms should be installed into your path, so you can go download some lovely skin of a brushed aluminium late-90s Sony CD player ... though it might be a little bit tiny if you use a HiDPI screen:

Grammatical cases are a common stumbling block for native English speakers learning another language. This might be because cases are sort of invisible in English and they're not taught in school so it's it's hard to see why they would even matter.

However in languages like Czech cases are a really important concept, and if you don't wrap your head around them you'll struggle to make yourself understood. To fully comprehend this importance we need an example - Petr and Pavel, who are not friends.

Accusative - Peter is punching Pavel

In Czech the verb "to punch" is "bít", whose third person conjugation is "bije" so if we want to describe this situation in Czech we might naively start out with something like this ...

Petr bije Pavel

However this isn't quite enough because it's not actually clear who is punching who. You should be able to rearrange the parts of this sentence in many ways in Czech without any ambiguity. But if we can rearrange the sentence as Pavel bije Petr or bije Pavel Petr then how do we tell our Czech friends who is the puncher and who is the punchee? This is where we need to modify case of some words to help clear things up a little.

In Czech we indicate the subject (puncher) using the nominative case. In our sentence this is Petr and the nominative case of Petr is simply Petr.

The object (the punchee) of the sentence is indicated using accusative case - which for Pavel is Pavla. Which gives us:

Petr bije Pavla

Genitive - Petr reads Helena's book