Racket preprocessor for CSS & HTML [unstable]
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#lang racket/base
(require racket/string racket/list)
(require sugar/unstable/string sugar/coerce)
(provide (all-defined-out))
(define (join-css-strings prop-strs)
(define prop-terminator ";")
(define newline "\n")
(define full-terminator (string-append prop-terminator newline))
(for/list ([prop-str (in-list prop-strs)])
(string-append prop-str
[(prop-str . ends-with? . full-terminator) ""]
[(prop-str . ends-with? . prop-terminator) newline]
[else full-terminator]))) ""))
(define (make-css-string p v)
(format "~a: ~a;" p v))
(define (make-css-strings property-prefixes property-suffix values)
; general function for creating groups of css properties
; with browser prefixes and one value
(define (map-suffix suffix prefixes)
(map (λ (prefix) (format "~a~a" prefix suffix)) prefixes))
(define properties (map-suffix property-suffix property-prefixes))
; if single value provided, convert to list of values
; so that it will work with map in the next step
(when (not (list? values))
(set! values (make-list (length properties) values)))
(map make-css-string properties values))
; editability can't be handled as pure css because firefox requires extra content-editable attribute.
; does it still? todo: further research, maybe this can be css only.
(define (editable . stuff)
(define editable-string (make-css-editable))
`(div ((style ,editable-string)(contenteditable "true")) ,@stuff))
(define (make-css-editable)
(join-css-strings (list "user-modify: read-write"
"outline-style: none")))
(define (make-media-query starting-size ending-size max-width interval [step-size 1])
(string-join (cons (format "@media all {html {font-size: ~apx;}}" starting-size)
(for/list ([size (in-range starting-size (sub1 ending-size) (* -1 step-size))]
#:unless (< size ending-size))
(format "@media all and (max-width:~apx){html {font-size: ~apx;}}"
(- max-width (* interval (- starting-size size))) size))) "\n"))
(module+ main
(displayln (make-media-query 15 11 980 60))
(displayln (make-media-query 15 11 980 60 .5)))
(define (make-css-ot-features feature-tags [feature-values 1])
; if single value provided, upconvert to list
(when (not (list? feature-tags))
(set! feature-tags (list feature-tags)))
; same here: convert single value into list
(when (not (list? feature-values))
(let ([single-value feature-values])
(set! feature-values (make-list (length feature-tags) single-value))))
; use single quotes in the formatter because css string might be used in an inline tag
; with form style="[string]" so double quotes are irritating
(define feature-tag-string (string-join (map (λ(tag value) (format "'~a' ~a" tag value)) feature-tags feature-values) ", "))
(define feature-tag-property "font-feature-settings")
(make-css-string feature-tag-property feature-tag-string))
(define (make-css-hyphens [value "auto"])
(make-css-string "hyphens" value))
(define (make-css-small-caps)
(join-css-strings (list "text-transform: lowercase" (make-css-ot-features "c2sc"))))
(define (make-css-caps)
(join-css-strings (list "text-transform: uppercase" (make-css-ot-features "case"))))
(define (make-css-kerning)
(join-css-strings (list "text-rendering: optimizeLegibility" (make-css-ot-features "kern"))))
(define (make-css-ligatures)
(join-css-strings (list "text-rendering: optimizeLegibility" (make-css-ot-features "liga"))))
(define (make-css-background-gradient colors [stops #f]
#:radial [radial #f]
#:horizontal [horizontal #f]
#:direction [direction #f])
; this doesn't handle old-style webkit syntax. todo: add it? I think I don't care
; check inputs for failure
(when (or (not (list? colors)) (< (length colors) 2))
(error "Not enough colors to make gradient in" colors))
(when (and stops (< (length stops) (length colors)))
(error "Not enough stops for given number of colors in" stops))
(when (not stops) ; distribute colors evenly between 0 and 100
; new-stops is range of steps incremented properly and rounded to int, then append 100 to end
(let ([new-stops `(,@(map floor (range 0 100 (/ 100 (sub1 (length colors))))) 100)])
; convert to list of percentages
(set! stops (map (λ(x) (format "~a%" x)) new-stops))))
; color / percentage pairs separated by commas
(define color-stop-string (string-join (map (λ(color stop) (format "~a ~a" color stop)) colors stops) ", "))
; set up gradient options
(define gradient-type (if radial "radial" "linear"))
(define gradient-direction
(format "~a~a" (if radial "circle at " "")
(if direction
(if horizontal "left" "top")
; can't use standard make-css-strings in this case because the prefixes appear in the value,
; not in the property (which is always "background")
(define gradient-string (format "background: ~a-gradient(~a, ~a)" gradient-type gradient-direction color-stop-string))
; just fill with the last color if gradient not available
(define fallback-string (format "background: ~a" (last colors)))
; put fallback string at front of list
(join-css-strings (list fallback-string gradient-string)))