chicken-scheme

name

chicken-scheme

description

Write, compile, debug, and package CHICKEN Scheme programs. Use this skill whenever the user mentions CHICKEN Scheme, call-cc.org, csc, csi, Scheme eggs, Scheme-to-C compilation, R5RS/R7RS Scheme, call/cc, continuations, SRFI, or wants help with any Scheme programming task using CHICKEN. Also trigger for questions about the CHICKEN FFI, C interop from Scheme, egg packaging, REPL usage, or scripting with csi. Even if the user just says "scheme" without specifying CHICKEN, use this skill if context suggests CHICKEN (e.g. they mention eggs, csc, chicken-install, or wiki.call-cc.org). DO NOT USE when: the user is working with another Scheme implementation (Racket, Guile, MIT Scheme, Gambit) — those have different module systems, package managers, and idioms.

CHICKEN Scheme Skill

CHICKEN is a Scheme-to-C compiler + interpreter. It produces portable, efficient C from Scheme source and supports R5RS / R7RS (via extension). The main commands are:

Command	Purpose
csi	Interactive interpreter (REPL)
csc	Compiler driver (Scheme → C → native binary)
chicken-install	Install eggs (libraries)
chicken-status	List installed eggs
chicken-uninstall	Remove an egg

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Quick-Start Workflow

;;; hello.scm
(import (chicken base))
(print "Hello, world!")

# Interpreted
csi -s hello.scm

# Compiled to executable
csc hello.scm          # produces ./hello
./hello

# Compiled as shared object (for loading into csi)
csc -shared hello.scm  # produces hello.so

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Egg System (Libraries)

chicken-install srfi-1         # list utilities
chicken-install matchable      # pattern matching
chicken-install http-client    # HTTP requests
chicken-install medea           # JSON parser

# Search eggs online: https://wiki.call-cc.org/eggs

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REPL Tips (csi)

,?          ; help
,l file     ; load a file
,t expr     ; time an expression
,d name     ; describe a binding
,q          ; quit

Enable readline: chicken-install breadline, then add to ~/.csirc:

(import breadline)
(current-input-port (make-readline-port))

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Common Pitfalls

• csc on Windows may conflict with the C# compiler — use a full path or rename.
• No use in CHICKEN 5 — replace (use foo) with (import foo).
• Dynamic loading requires a shared library on the CHICKEN_REPOSITORY_PATH.
• call/cc is powerful but sharp — prefer high-level abstractions (threads, conditions) over raw continuations in application code.
• Unsafe mode (-unsafe) disables all safety checks — only use for hot inner loops after profiling.

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Integrated Example

Goal: a CLI tool that reads a JSON file and prints how many records it has.

;;; count.scm
(import (chicken base)
        (chicken file)        ; read-string
        medea)                ; egg: read-json — NOT (use medea)

(define data (with-input-from-file (car (command-line-arguments)) read-json))
(printf "~a records~%" (length data))

chicken-install medea        # install the JSON egg first
csc count.scm                # Scheme → C → ./count
./count records.json         # => 42 records

The medea egg is pulled in with (import medea) — in CHICKEN 5 there is no use. csc compiles to a native binary in one step; for quick iteration csi -s count.scm records.json runs the same source interpreted.

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Read On Demand

Read When	File
Modules, imports, tail recursion, call/cc, macros, records	Core Language
Scripting, shebang, CLI tools, compiler flag examples, egg structure	Scripting & CLI
FFI: foreign-lambda, callbacks, C interop, embedding	FFI Guide
Egg authoring, testing, and publishing workflow	Egg System