fraktur

#!/usr/local/bin/guile -s
!#
;; Hey emacs this is -*- scheme -*- code
(eval-when (compile load eval)
  (set! %load-extensions '(".guile.sls" ".sls" ".ss" ".scm" "")))

(import (ijputils strings)
        (only (rnrs) let*-values)
        (ice-9 match))

; 𝘠𝘰𝘶𝘳 𝘴𝘵𝘳𝘢𝘵𝘦𝘨𝘪𝘦𝘴 𝘩𝘢𝘷𝘦 𝙣𝙤 𝘦𝘧𝘧𝘦𝘤𝘵 𝘰𝘯 𝘮𝘦.
; <offby1> ¿ɯǝlqoɹd ɹnoʎ s‚ʇɐɥʍ ;ʞɐǝds I uǝɥʍ ɹɐǝlɔ ʎlʇɔǝfɹǝd ɯ‚I
(define alphabetic "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
(define fraktur "𝔄𝔅ℭ𝔇𝔈𝔉𝔊ℌℑ𝔍𝔎𝔏𝔐𝔑𝔒𝔓𝔔ℜ𝔖𝔗𝔘𝔙𝔚𝔛𝔜ℨ𝔞𝔟𝔠𝔡𝔢𝔣𝔤𝔥𝔦𝔧𝔨𝔩𝔪𝔫𝔬𝔭𝔮𝔯𝔰𝔱𝔲𝔳𝔴𝔵𝔶𝔷")
(define fullwidth "ＡＢＣＤＥＦＧＨＩＪＫＬＭＮＯＰＱＲＳＴＵＶＷＸＹＺａｂｃｄｅｆｇｈｉｊｋｌｍｎｏｐｑｒｓｔｕｖｗｘｙｚ") ;; TODO: add a fullwidth space "ｈｅｌｌｏ　ｔｈｅｒｅ"
(define upside-down "")
;; small letter small capitals?
(define (frakturify string)
  (string-translate string alphabetic fraktur))

(define (fullwidthify string)
  (string-translate string alphabetic fullwidth))

(define (upside-downify string)
  (string-reverse (string-translate string alphabetic upside-down)))

(define (lookup s)
  ;; TODO: create a translation specification structure
  (match s
    ("fraktur" (values frakturify #f))
    ("fullwidth" (values fullwidthify #f))
    ("flip" (values upside-downify #t))
    (else (values identity #f))))

(define (main args)
  (let*-values ([(convert reverse?)
                 (lookup (basename (car args)))]
                [(join) (if reverse?
                            (compose string-join reverse)
                            string-join)])
    (display (join (map convert (cdr args))))
    (newline)))

(setlocale LC_ALL "")
(main (command-line))

strings.sls

#!r6rs
(library (ijputils strings)
(export string-translate)
(import (rnrs base)
        (only (srfi :13 strings) string-index string-map))

(define (string-translate string from to)
  (define (convert c)
    (cond ((string-index from c) =>
           (lambda (i)
             (string-ref to i)))
          (else c)))
  (string-map convert string))

)