/skorbut-release

Let us C what's going on in memory!

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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.

Recent features

2023-06 persist multiple editors
2023-05 jump to declaration / find usages
2023-05 rename symbol
2022-12 overhaul memory visualizer
2022-11 hide unused static variables
2022-11 hide unused string literals
2022-11 expand char from ASCII to Latin-1
2022-11 retain console focus after STEP button clicks
2022-10 report passed assertions
2022-06 F1/right-click on expression or declarator name reveals type
2022-05 Program execution can start inside any void function()
2020-08 hide variables starting with an underscore
2020-08 auto-complete members globally
2020-02 cast expressions
2019-07 auto-complete non-member identifiers

Getting started

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

☕ Windows & macOS

  1. Visit https://adoptium.net

  2. Click "Latest release" button to download Java installer

  3. Wait for download to finish

  4. Open the Downloads folder (via Windows Explorer or Finder/Spotlight, respectively) and double-click OpenJDK... to start Java installer

  5. Click Next, Next, Install, Finish

  6. Click skorbut.jar to download Skorbut
    If Skorbut fails to download, continue with ⚠️ Troubleshooting Windows, or ⚠️ Troubleshooting macOS

  7. 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/master/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/master/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/master/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.

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 };

Is Skorbut open source?

Not yet, but I will probably open-source Skorbut when I lose interest in further development. Don't hold your breath though 😉

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