Goldfish Scheme / 金鱼 Scheme

Make Scheme as easy to use and practical as Python!

Goldfish Scheme is a Scheme interpreter with the following features:

• R7RS-small compatible
• Scala-like functional collection
• Python-like versatile standard library
• Small and fast

Demo Code

Named parameter

(define* (person (name "Bob") (age 21))
  (string-append name ": " (number->string age)))

(person :name "Alice" :age 3)

Unicode Support

(import (liii lang))

($ "你好，世界" 0) ; => 你
($ "你好，世界" 4) ; => 界
($ "你好，世界" :length) ; => 5

Functional Data Pipeline

With prime? provided, filter twin prime numbers in this way:

(import (liii lang))

(($ 1 :to 100)
 :filter prime?
 :filter (lambda (x) (prime? (+ x 2)))
 :map (lambda (x) (cons x (+ x 2)))
 :collect)

Scala like case class

(define-case-class person
  ((name string?)
   (age integer?))

  (define (%to-string)
    (string-append "I am " name " " (number->string age) " years old!"))
  (define (%greet x)
    (string-append "Hi " x ", " (%to-string))))

(define bob (person "Bob" 21))

(bob :to-string) ; => "I am Bob 21 years old!"
(bob :greet "Alice") ; => "Hi Alice, I am Bob 21 years old!"

Performance Warning: define-case-class is implemented via macros and has significant performance overhead. It is suitable for hand-written code and prototyping, but not recommended for AI-generated code or production deployments.

Simplicity is Beauty

Goldfish Scheme still follows the same principle of simplicity as S7 Scheme. Currently, Goldfish Scheme only depends on S7 Scheme, tbox and C++ standard library defined in C++ 98.

Just like S7 Scheme, src/goldfish.hpp and src/goldfish.cpp are the only key source code needed to build the goldfish interpreter binary.

Standard Library

Scala-like collections

Library	Description
(liii rich-char)	boxed char with rich char and instance methods
(liii rich-string)	boxed string with rich char and instance methods
(liii rich-list)	boxed list with rich static and instance methods
(liii rich-vector)	boxed vector with rich static and instance methods
(liii rich-hash-table)	boxed hash-table with rich static and instance methods
(liii rich-path)	boxed path with rich static and instance methods

Python-like standard library

Library	Description	Example functions
(liii base)	Basic routines	==, !=, display*
(liii error)	Python like Errors	os-error to raise 'os-error just like OSError in Python
(liii check)	Test framework based on SRFI-78	check, check-catch
(liii case)	Pattern matching	case*
(liii list)	List Library	list-view, fold
(liii bitwise)	Bitwise Library	bitwise-and, bitwise-or
(liii string)	String Library	string-join
(liii vector)	Vector Library	vector-index
(liii hash-table)	Hash Table Library	hash-table-empty?, hash-table-contains?
(liii sys)	Library looks like Python sys module	argv
(liii os)	Library looks like Python os module	getenv, mkdir
(liii path)	Path Library	path-dir?, path-file?
(liii range)	Range Library	numeric-range, iota
(liii option)	Option Type Library	option?, option-map, option-flatten
(liii uuid)	UUID generation	uuid4

SRFI

Library	Status	Description
(srfi srfi-1)	Part	List Library
(srfi srfi-8)	Complete	Provide receive
(srfi srfi-9)	Complete	Provide define-record-type
(srfi srfi-13)	Complete	String Library
(srfi srfi-16)	Complete	Provide case-lambda
(srfi srfi-39)	Complete	Parameter Objects
(srfi srfi-78)	Part	Lightweigted Test Framework
(srfi srfi-125)	Part	Hash Table
(srfi srfi-133)	Part	Vector
(srfi srfi-151)	Part	Bitwise Operations
(srfi srfi-196)	Complete	Range Library
(srfi srfi-216)	Part	SICP

R7RS Standard Libraries

Library	Description
(scheme base)	Base library
(scheme case-lambda)	Provide case-lambda
(scheme char)	Character Library
(scheme file)	File operations
(scheme time)	Time library

Installation

Goldfish Scheme is bundled in Mogan Research (since v1.2.8), just install Mogan Research to install Goldfish Scheme.

Besides the Goldfish Scheme interpreter, a nice structured Goldfish Scheme REPL is availabe in Mogan Research.

The following guide will help you build and install Goldfish step by step.

GNU/Linux

Here are commandlines to build it on Debian bookworm:

sudo apt install xmake git unzip curl g++
git clone https://gitee.com/LiiiLabs/goldfish.git
# git clone https://github.com/LiiiLabs/goldfish.git
cd goldfish
xmake b goldfish
bin/gf --version

You can also install it to /opt:

sudo xmake i -o /opt/goldfish --root
/opt/goldfish/bin/gf

For uninstallation, just:

sudo rm -rf /opt/goldfish

Commandlinefu

This section assumes you have executed xmake b goldfish sucessfully and bin/gf is available.

Subcommands

Goldfish Scheme uses subcommands for different operations:

Subcommand	Description
help	Display help message
version	Display version information
eval CODE	Evaluate Scheme code
load FILE	Load Scheme file and enter REPL
repl	Enter interactive REPL mode
run TARGET	Run main function from target
test	Run tests
fix PATH	Format Scheme code
FILE	Load and evaluate Scheme file directly

Display Help

Without any command, it will print the help message:

> bin/gf
Goldfish Scheme 17.11.32 by LiiiLabs

Commands:
  help               Display this help message
  version            Display version
  eval CODE          Evaluate Scheme code
  load FILE          Load Scheme code from FILE, then enter REPL
  ...

Display Version

version subcommand will print the Goldfish Scheme version and the underlying S7 Scheme version:

> bin/gf version
Goldfish Scheme 17.11.32 by LiiiLabs
based on S7 Scheme 11.5 (22-Sep-2025)

Evaluate Code

eval subcommand helps you evaluate Scheme code on the fly:

> bin/gf eval "(+ 1 2)"
3
> bin/gf eval "(begin (import (srfi srfi-1)) (first (list 1 2 3)))"
1
> bin/gf eval "(begin (import (liii sys)) (display (argv)) (newline))" 1 2 3
("bin/gf" "eval" "(begin (import (liii sys)) (display (argv)) (newline))" "1" "2" "3")

Load File

load subcommand helps you load a Scheme file and enter REPL:

> bin/gf load tests/goldfish/liii/base-test.scm
; load the file and enter REPL

Run File Directly

You can also load and evaluate a Scheme file directly:

> bin/gf tests/goldfish/liii/base-test.scm
; *** checks *** : 1973 correct, 0 failed.

Mode Option

-m or --mode helps you specify the standard library mode:

• default: -m default is the equiv of -m liii
• liii: Goldfish Scheme with (liii oop), (liii base) and (liii error)
• scheme: Goldfish Scheme with (liii base) and (liii error)
• sicp: S7 Scheme with (scheme base) and (srfi sicp)
• r7rs: S7 Scheme with (scheme base)
• s7: S7 Scheme without any extra library

Versioning

Goldfish Scheme x.y.z means that it is using the tbox x, based on S7 Scheme y, and z is the patch version. To clarify, the second version of Goldfish Scheme is 17.10.1, it means that it is using tbox 1.7.x, based on S7 Scheme 10.x, the patch version is 1.

Why we created Goldfish Scheme

Goldfish Scheme is implemented to overcome the defects of S7 Scheme:

1. Distribute the ready-to-use Goldfish Scheme interpreter and structured REPL on Linux/macOS/Windows
2. Try to implement the R7RS-small standard
3. Try to provide the useful SRFI in R7RS library format

License

Goldfish Scheme is licensed under Apache 2.0, some of the code snippets which are derived from the S7 Scheme repo and SRFI have been explicitly claimed in the related source files.

Citation

The reader can cite our work with the following BibTeX entry:

@book{goldfish,
    author = {Da Shen and Nian Liu and Yansong Li and Shuting Zhao and Shen Wei and Andy Yu and Siyu Xing and Jiayi Dong and Yancheng Li and Xinyi Yu and Zhiwen Fu and Duolei Wang and Leiyu He and Yingyao Zhou and Noctis Zhang},
    title = {Goldfish Scheme: A Scheme Interpreter with Python-Like Standard Library},
    publisher = {LIII NETWORK},
    year = {2024},
    url = {https://github.com/LiiiLabs/goldfish/releases/download/v17.10.9/Goldfish.pdf}
}