repo2html/utils.scm
pho4cexa c943210189 minor improvements to modular compilation
- rename main.scm to repo2html.scm to match binary
- remove unused imports from utils.scm
2023-02-04 22:45:21 -08:00

88 lines
2.9 KiB
Scheme

;; small utilities ---------------------------------
(module utils *
(import
scheme
(chicken base)
(chicken pathname)
(clojurian syntax)
srfi-1 ;; list utils
)
;; (bail [message [exit-status]])
;; end the program immediately.
;; if a message is provided, print it to the screen.
;; exit-status defaults to 1.
(define (bail #!optional msg (status 1))
(when msg (print msg))
(exit status))
;; clojureish "debugging by print statement" tool since i still haven't reached
;; lisp enlightenment
(define ((inspect #!optional label #!rest args) s)
(display (list label ":" args " => " s) (current-error-port))
(newline (current-error-port))
s)
;; decompose a path s into its constituent parts. returns values:
;;
;; root: "/" if it's an absolute path, "" if relative directory-elements: a list
;; of each directory from root, () if none basename: the filename with extension
;; removed like "readme" or ".bashrc" extension: the file extension with the
;; dot, like ".txt" or "" if none relative-root: the relative path from the
;; given path to the root
;; e.g foo/bar/baz.html -> ../../
;;
;; this is intended to provide default values that make for easier reassembly
;; into filenames.
;;
;; typical use:
;; (->> source-file
;; (pathparts)
;; (define-values (root elements basename extension relative-root)))
;;
(define (pathparts s)
(define-values (dirname basename extension)
(decompose-pathname s))
(define-values (origin root directory-elements)
(decompose-directory (or dirname "")))
;; discarding origin because idgaf about windows
(values (or root "")
(or directory-elements '())
basename
(if extension (string-append "." extension) "")
(->>
(or directory-elements '())
(map (constantly "../"))
(apply string-append))))
;; like (substring) but doesn't break if start and end are too big/small
(define (substring* s start end)
(substring s (max start 0) (min end (string-length s))))
;; merge alists a and b. values in b "win"
(define (alist-merge a b)
(lset-union (lambda (x y) (eq? (car x) (car y))) a b))
;; like alist-ref but works on nested alists by specifying a path (list of keys)
(define (alist-ref-in keys alist #!optional (test eqv?))
(if (null? (cdr keys))
(alist-ref (car keys) alist test)
(alist-ref-in (cdr keys) (alist-ref (car keys) alist test) test)))
;; like alist-update, but works on nested alists by specifying a path (list of
;; keys)
(define (alist-update-in keys value alist #!optional (test eqv?))
(cond
((not alist) #f)
((null? (cdr keys))
(alist-update (car keys) value alist test))
(else
(alist-update (car keys)
(alist-update-in (cdr keys) value (alist-ref (car keys) alist test) test)
alist test))))
(define (unless-equals s1 s2)
;; if s1 == s2, then s1, otherwise #f
(and (equal? s1 s2) s1))
)