skorbut: A Kotlin repository from fredoverflow

What is Skorbut?

Skorbut is a simple teaching environment for a subset of C with a memory visualizer. If you ever had trouble visualizing arrays and pointers, you have come to the right place.

Skorbut is German for scurvy, an illness that is caused by a lack of Vitamin C. Skorbut also lacks C in the sense that it implements only a restricted subset of C.

Getting started

Please take the time to read the following instructions carefully. Most problems stem from skipping or misunderstanding important steps.

☕ Windows & macOS

Visit https://adoptium.net
Click "Latest release" button to download Java installer
Wait for download to finish
Open the Downloads folder (via Windows Explorer or Finder/Spotlight, respectively) and double-click OpenJDK... to start Java installer
Click Next, Next, Install, Finish
Click skorbut.jar to download Skorbut
If Skorbut fails to download, continue with ⚠️ Troubleshooting Windows, or ⚠️ Troubleshooting macOS
Open the Downloads folder and double-click skorbut.jar to start Skorbut
If Skorbut fails to start, continue with ⚠️ Troubleshooting Windows, or ⚠️ Troubleshooting macOS

⚠️ Troubleshooting Windows

Steps 1 through 5 (install Java) worked, but steps 6 (download Skorbut) or 7 (start Skorbut) failed? Then read on.

Move your mouse over the script below
A button appears in the top right corner of the script
Click that button to copy the script

cd Downloads
if exist skorbut.jar.zip erase skorbut.jar.zip
curl -o skorbut.jar https://raw.githubusercontent.com/fredoverflow/skorbut/release/skorbut.jar
echo java -version > skorbut.cmd
echo java -jar skorbut.jar >> skorbut.cmd
skorbut.cmd

Press the Windows key (the key on the bottom left with the Windows logo ⊞ on it)
Write cmd and confirm with Enter
A terminal appears
Right-click anywhere inside that terminal to paste and execute the script

From now on, simply double-click skorbut.cmd in the Downloads folder to start Skorbut.
Feel free to move skorbut.jar and skorbut.cmd to the Desktop or any other folder you prefer.

⚠️ Troubleshooting macOS

Steps 1 through 5 (install Java) worked, but steps 6 (download Skorbut) or 7 (start Skorbut) failed? Then read on.

Move your mouse over the script below
A button appears in the top right corner of the script
Click that button to copy the script

cd Downloads
curl -o skorbut.jar https://raw.githubusercontent.com/fredoverflow/skorbut/release/skorbut.jar
chmod +x skorbut.jar
echo java -version > skorbut.sh
echo java -jar skorbut.jar >> skorbut.sh
chmod +x skorbut.sh
./skorbut.sh

Press Command⌘ Space (or click the magnifying glass 🔍 in the top right corner of the screen) to open Spotlight
Write terminal and confirm with Enter
A terminal appears
Press Command⌘ V to paste and execute the script

From now on, simply double-click skorbut.sh in the Downloads folder to start Skorbut.
Feel free to move skorbut.jar and skorbut.sh to the Desktop or any other folder you prefer.

🐧 Ubuntu, Linux Mint, Debian...

sudo apt install default-jdk
cd Downloads
curl -o skorbut.jar https://raw.githubusercontent.com/fredoverflow/skorbut/release/skorbut.jar
chmod +x skorbut.jar
echo java -version > skorbut.sh
echo java -jar -Dsun.java2d.opengl=True skorbut.jar >> skorbut.sh
chmod +x skorbut.sh
./skorbut.sh

From now on, simply double-click skorbut.sh in the Downloads folder to start Skorbut.
Feel free to move skorbut.jar and skorbut.sh to the Desktop or any other folder you prefer.

I would rather compile Skorbut from source!

git clone https://github.com/fredoverflow/freditor
cd freditor
mvn install
cd ..
git clone https://github.com/fredoverflow/skorbut
cd skorbut
mvn package

The executable skorbut.jar will be located inside the target folder.

How do I save my code?

The code is automatically saved to a new file each time you click the start button. The save folder is named skorbut, and it is located in your home directory. The full path is displayed in the title bar.

Does Skorbut support auto-indentation?

Yes, just hit Enter or Tab.

What about auto-completion?

Ctrl+Space after an identifier auto-completes to the longest common prefix of all identifiers in scope. For example, if foo, bar and baz are in scope, then f will be auto-completed to foo, but b will only be auto-completed to ba, because both bar and baz start with ba.

Skorbut has scope-aware auto-completion for all identifiers except struct members; those are auto-completed globally, i.e. after . or ->, all struct members are considered for auto-completion. (That's because auto-completion has no type information available yet. Changing this would be a Herculean task.)

What features of C are currently missing?

Non-exhaustive list off the top of my head:

Feature	Priority
preprocessor	very low
variadic functions	very low
compound assignment	low
null pointer	medium
union	very low
return struct	low

Wait, no preprocessor? How do I `#include <stdio.h>`?

You don't need to include anything, the following standard library functions are already available:

printf
scanf
puts
putchar
getchar
malloc
free
realloc
qsort
bsearch
strlen
strcmp
pow
time

What about my own header files?

Skorbut does not support multiple translation units, so there would be no point in supporting header files.

How do I define constants without `#define`?

For integral constants, you can use anonymous enumerations like enum { N = 10 };

Keyboard shortcuts

Windows	Effect	Macintosh
F1	show type	F1
F3	declaration usages	F3
F5	step into	F5
F6	step over	F6
F7	step return	F7
Tab Enter	auto-indent	Tab Enter
Ctrl Space	auto-complete	Control (Shift) Space
Ctrl Alt R	rename symbol	Command Option R
Ctrl D	delete line	Command D
Ctrl C	copy	Command C
Ctrl X	cut	Command X
Ctrl V	paste	Command V
Ctrl Z	undo	Command Z
Ctrl Y	redo	Command Y

fredoverflow/skorbut