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🍬 Jelly — The Language Built for Code Golf and Extreme Compression

What is Jelly?

Jelly is a modern esoteric programming language created by Dennis Mitchell. It was designed specifically for code golf — the challenge of writing programs with the fewest characters possible. Jelly includes many built-in operations, Unicode symbols, stack-based behavior, list processing, functional patterns, and clever shortcuts that allow complex tasks to be written in only a few characters.

Jelly evolved as a successor to languages like GolfScript and J, combining heavy symbolic expressiveness with automation of common algorithmic patterns. The result is a highly powerful but extremely cryptic syntax where solutions look like puzzles rather than code.

Specs

Language Type: Code Golf / Esoteric

Creator: Dennis Mitchell

Execution Model: Tacit, list-oriented, stack evaluation

Character Set: Unicode symbols + ASCII

Purpose: Write the shortest possible programs

CODE EXAMPLE (Hello World)

A Jelly “Hello World” program can be as short as:

“Hello World”
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In Jelly, smart printing and evaluation make this a complete working program.

How It Works

  • Jelly is stack-based but supports higher-order functions, mapping, and vectorization.
  • Many operations automatically apply across lists without explicit loops.
  • Special Unicode symbols represent multi-step operations, for example:
    • mathematical operations
    • sorting
    • string manipulation
    • combinatorics
    • encoding and parsing
  • Because many operations are implicit, short programs can perform very complex tasks.

Programmers rarely read Jelly — they decode it like a cipher.

Strengths

  • Extremely compact and expressive.
  • Excellent for competitive code golf.
  • Built-in support for many common tasks, including:
    • prime generation
    • string processing
    • math functions
    • recursive patterns
  • Ideal playground for experimenting with dense symbolic programming.

Weaknesses

  • Very steep learning curve due to dense symbolic syntax.
  • Hard to debug without specialized tools.
  • Unicode character entry can be inconvenient.
  • Programs become unreadable even to the original author after time.

Where to Run

Jelly can be executed in:

  • TIO.run (most common)
  • Online interactive playgrounds
  • Local interpreters built from GitHub source

Some editors provide on-hover symbol explanations.

Should You Learn It?

For real-world programming: No

For competitive code golf: Yes — one of the best choices

For exploring dense symbolic languages: Absolutely

For writing clear, maintainable software: No chance

Summary

Jelly pushes the limits of how compact programming languages can be. With Unicode symbols, powerful built-ins, and implicit behaviors, Jelly allows extremely short solutions to complex problems — making it one of the most important languages in the code-golf scene. While unreadable for normal development, Jelly remains a brilliant example of compression-focused language design.

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