rfalse

An interpreter for the FALSE language — possibly the fastest in the world.

• Supports all language features;
• Written in Rust;
• Up to 38 times more performant than false-js (see benchmarks below). If you are aware of any faster implementations, please let me know!

Table of Contents

• Benchmarks
• How to run
• WASM support
• Hacking
• License
• See also

Benchmarks

Test	false-js	rfalse	difference
Primes, n=1999	4392 ms	168 ms	~26x
Fibonacci, n=33	37597 ms	987 ms	~38x
Fibonacci, n=25	802 ms	21 ms	~38x

Experimental VM:

Test	rfalse-vm2	false-js	solkin/false-vm
Primes, n=1999	102 ms	4392 ms (~43x slower)	154 ms (~1.5x slower)
Fibonacci, n=33	435 ms	37597 ms (~86x slower)	504 ms (~1.16x slower)
Fibonacci, n=25	9 ms	802 ms (~89x slower)	11 ms (~1.2x slower)

How to run

cargo run --release -- examples/hello.false

In no filename is given, stdin will be used instead.

WASM support

Experimental feature. WASM performance is about 2x worse than native build.

First, compile the WASM files:

wasm-pack build --release --target web

After that, run a webserver. For example:

python3 -m http.server 8000 -d .

Navigate to http://localhost:8000 and open the console.

Hacking

Run linter:

cargo clippy

Run tests:

cargo test

Run benchmarks:

cargo bench --bench perf

License

GNU LGPL v3

See also

• FALSE home page
• FALSE page on Esolangs — the closest thing we have to a language reference
• Archived language reference, was very hard to find
• FALSE article on Russian Wikipedia which contains some useful explanations; funny enough, there's no English version

Other notable implementations:

• Awesome FALSE interpreter by Igor Solkin
• false-js by Ian Osgood
• JavaScript FALSE interpreter by Anthony Morphett