SRFI Skill

"SRFIs extend the Scheme programming language. You can help." — srfi.schemers.org

Scheme Requests for Implementation: portable library specifications with GF(3) categorization.

Overview

SRFIs are community-driven specifications that extend Scheme beyond R5RS/R6RS/R7RS. Each SRFI has a unique number, status (draft/final/withdrawn), and reference implementation.

Core SRFIs by Category

Data Structures [MINUS: -1]

SRFI	Name	Status	Key Exports
1	List Library	Final	fold, unfold, filter, partition
4	Homogeneous Vectors	Final	u8vector, f64vector, typed arrays
9	Defining Record Types	Final	define-record-type
14	Character Sets	Final	char-set, char-set-contains?
69	Basic Hash Tables	Final	make-hash-table, hash-table-ref
113	Sets and Bags	Final	set, bag, set-contains?
125	Intermediate Hash Tables	Final	hash-table-map, comparators
128	Comparators (Reduced)	Final	make-comparator, comparator-hash
133	Vector Library	Final	vector-map, vector-fold
146	Mappings	Final	mapping, functional maps
158	Generators and Accumulators	Final	make-coroutine-generator

Control Flow [ERGODIC: 0]

SRFI	Name	Status	Key Exports
2	AND-LET*	Final	and-let* short-circuit binding
8	receive	Final	receive for multiple values
11	let-values	Final	let-values, let*-values
18	Multithreading	Final	make-thread, mutex, condition-variable
34	Exception Handling	Final	guard, raise
39	Parameter Objects	Final	make-parameter, parameterize
45	Primitives for Lazy Eval	Final	delay, force, lazy
124	Ephemerons	Final	make-ephemeron, weak references
154	First-Class Dynamic Extents	Final	dynamic-extent, delimited continuations
155	Promises	Final	delay-force, iterative lazy
226	Control Features	Final	call/cc, values, dynamic-wind

Syntax & Macros [PLUS: +1]

SRFI	Name	Status	Key Exports
0	Feature-Based Conditionals	Final	cond-expand
6	Basic String Ports	Final	open-input-string, get-output-string
26	Cut/Cute	Final	cut, cute partial application
42	Eager Comprehensions	Final	list-ec, sum-ec, do-ec
46	Syntax for Multiple Values	Final	values->list, values->vector
57	Records	Withdrawn	(superseded by 99, 136)
72	Hygienic Macros	Final	syntax-case compatible
139	Syntax Parameters	Final	define-syntax-parameter
147	Custom Macro Transformers	Final	er-macro-transformer
149	Basic Syntax-Rules Extensions	Final	_, ... patterns
211	Scheme Macros for Definitions	Final	define-macro

I/O & System [MINUS: -1]

SRFI	Name	Status	Key Exports
6	Basic String Ports	Final	in-memory I/O
28	Basic Format Strings	Final	format
38	External Representation with Cycles	Final	write/ss, read/ss
48	Intermediate Format Strings	Final	format with more directives
106	Basic Socket Interface	Final	make-client-socket, socket-send
170	POSIX API	Final	file-info, set-file-mode!
180	JSON	Final	json-read, json-write
192	Port Positioning	Final	port-position, set-port-position!
193	Command Line	Final	command-line, option-processor

Numeric [ERGODIC: 0]

SRFI	Name	Status	Key Exports
27	Sources of Random Bits	Final	random-integer, random-real
60	Integers as Bits	Final	bitwise-and, bit-set?
94	Type-Restricted Numerics	Final	fx+, fl*
141	Integer Division	Final	floor/, ceiling/, truncate/
143	Fixnums	Final	fx+, fxarithmetic-shift
144	Flonums	Final	fl+, flsin, flexp
151	Bitwise Ops on Arbitrary Integers	Final	bitwise-ior, integer-length
166	Monadic Formatting	Final	format with monadic composition

Testing & Debugging [PLUS: +1]

SRFI	Name	Status	Key Exports
64	A Scheme API for Test Suites	Final	test-begin, test-equal, test-assert
78	Lightweight Testing	Final	check, check-ec
219	Define Higher-Order Lambda	Final	define with curry

Pattern Matching [PLUS: +1]

SRFI	Name	Status	Key Exports
204	Wright-Cartwright-Shinn Pattern Matcher	Final	match, match-lambda

GF(3) Distribution

MINUS (-1):  Data Structures, I/O & System
ERGODIC (0): Control Flow, Numeric
PLUS (+1):   Syntax & Macros, Testing, Pattern Matching

Conservation: Σ(categories) ≡ 0 (mod 3) when balanced usage

R7RS-Large Libraries (Red/Tangerine Editions)

R7RS-Large incorporates SRFIs as standard libraries:

Red Edition (2019)

• (scheme list) ← SRFI 1
• (scheme vector) ← SRFI 133
• (scheme sort) ← SRFI 132
• (scheme set) ← SRFI 113
• (scheme charset) ← SRFI 14
• (scheme hash-table) ← SRFI 125
• (scheme ilist) ← SRFI 116
• (scheme rlist) ← SRFI 101
• (scheme ideque) ← SRFI 134
• (scheme text) ← SRFI 135
• (scheme generator) ← SRFI 158
• (scheme lseq) ← SRFI 127
• (scheme stream) ← SRFI 41
• (scheme box) ← SRFI 111
• (scheme list-queue) ← SRFI 117
• (scheme comparator) ← SRFI 128

Tangerine Edition (2021)

• (scheme bitwise) ← SRFI 151
• (scheme fixnum) ← SRFI 143
• (scheme flonum) ← SRFI 144
• (scheme division) ← SRFI 141
• (scheme bytevector) ← R6RS
• (scheme mapping) ← SRFI 146
• (scheme regex) ← SRFI 115

Implementation Support Matrix

SRFI	Chez	Chicken	Gauche	Guile	Racket
1	✓	✓	✓	✓	✓
9	✓	✓	✓	✓	✓
18	✓	✓	✓	✓	✓
27	✓	✓	✓	✓	✓
64	✓	✓	✓	✓	✓
125	✓	✓	✓	✓	✓
158	✓	✓	✓	✓	✓
180	✓	✓	✓	✓	✓

SRFI-27: Random Sources (Key for Gay.jl Bridge)

;; SRFI-27 provides the abstraction layer for splittable RNG
(import (srfi 27))

;; Create a random source with specific seed
(define my-source (make-random-source))
(random-source-pseudo-randomize! my-source 1069 42)

;; Get integers and reals
(define rand-int (random-source-make-integers my-source))
(define rand-real (random-source-make-reals my-source))

;; GF(3) trit from random source
(define (random-trit source)
  (- ((random-source-make-integers source) 3) 1))

SRFI-171: Transducers

;; Composable sequence transformations
(import (srfi 171))

;; Filter, map, take composed
(define xform
  (compose
    (tfilter even?)
    (tmap (lambda (x) (* x x)))
    (ttake 5)))

;; Apply to list
(list-transduce xform rcons '(1 2 3 4 5 6 7 8 9 10))
;; => (4 16 36 64 100)

SRFI-204: Pattern Matching

(import (srfi 204))

;; Destructuring with guards
(match '(1 2 3)
  ((x y z) (guard (< x y z)) (list z y x))
  (_ 'no-match))
;; => (3 2 1)

;; Quasiquote patterns
(match '(lambda (x) (+ x 1))
  (`(lambda (,var) (+ ,var 1)) var)
  (_ #f))
;; => x

Integration with Little Schemer

SRFI	Little Schemer Concept
1	member?, rember, firsts
9	Atoms as records
27	Y combinator with random exploration
45	Lazy evaluation (Seasoned Ch. 16)
154	Continuations (Seasoned Ch. 13)
171	Collectors as transducers
204	Pattern matching vs cond

Commands

# Search SRFIs by keyword
srfi search "hash table"

# Show SRFI abstract
srfi show 125

# Clone SRFI implementation
srfi clone 171

# Open in browser
srfi open 204

# List all final SRFIs
srfi list --status final

References

• srfi.schemers.org - Official SRFI home
• docs.scheme.org/srfi/support - Implementation matrix
• R7RS-Large - Standard incorporation
• Practical Scheme SRFI Cross-Reference