Add css lexer.

2 files changed, 604 insertions, 8 deletions

diff --git a/syntax-highlight/css.scm b/syntax-highlight/css.scm
new file mode 100644
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--- /dev/null
+++ b/syntax-highlight/css.scm
@@ -0,0 +1,563 @@
+;;; guile-syntax-highlight --- General-purpose syntax highlighter
+;;; Copyright © 2021 Julien Lepiller <julien@lepiller.eu>
+;;;
+;;; Guile-syntax-highlight is free software; you can redistribute it
+;;; and/or modify it under the terms of the GNU Lesser General Public
+;;; License as published by the Free Software Foundation; either
+;;; version 3 of the License, or (at your option) any later version.
+;;;
+;;; Guile-syntax-highlight is distributed in the hope that it will be
+;;; useful, but WITHOUT ANY WARRANTY; without even the implied
+;;; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+;;; See the GNU Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with guile-syntax-highlight.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Syntax highlighting for css files.
+;; See https://www.w3.org/TR/css-syntax-3
+;;
+;;; Code:
+
+(define-module (syntax-highlight css)
+  #:use-module (ice-9 match)
+  #:use-module (syntax-highlight lexers)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
+  #:use-module (srfi srfi-26)
+  #:export (lex-css))
+
+;; From various documents
+(define %css-functions
+  '(;; https://www.w3.org/TR/css-transforms-1/
+    "translate" "scale" "rotate" "skewX" "skewY" "matrix" "translateX"
+    "translateY" "scaleX" "scaleY" "skew" "translate3d"
+    ;; https://www.w3.org/TR/css-values-3/
+    "calc" "attr"
+    ;; https://www.w3.org/TR/css-variables-1/
+    "var"
+    ;; https://www.w3.org/TR/css-color-3/
+    "rgb" "rgba" "hsl" "hsla"
+    ;; https://www.w3.org/TR/css-color-4/
+    "color" "lch" "hwb" "lab"
+    ;; https://www.w3.org/TR/css-images-3/
+    "linear-gradient" "radial-gradient" "repeating-linear-gradient"
+    "repeating-radial-gradient"
+    ;; https://www.w3.org/TR/css-easing-1/
+    "cubic-bezier" "steps"))
+
+(define %css-vendor-prefixes
+  ;; from https://www.w3.org/TR/CSS2/syndata.html#vendor-keywords
+  '("-ms-" "mso-" "-moz-" "-o-" "-xv-" "-atsc-" "-khtml-" "-webkit-"
+    "prince-" "-ah-" "-hp-" "-ro-" "-rim-" "-tc-"))
+
+;; from https://www.w3.org/Style/CSS/all-properties.en.html
+(define %css-properties
+  '("accent-color" "align-content" "align-items" "align-self"
+    "alignment-baseline" "all" "animation" "animation-delay"
+    "animation-direction" "animation-duration" "animation-fill-mode"
+    "animation-iteration-count" "animation-name" "animation-play-state"
+    "animation-timing-function" "appearance" "aspect-ratio" "azimuth"
+    "backface-visibility" "background" "background-attachment"
+    "background-blend-mode" "background-clip" "background-color"
+    "background-image" "background-origin" "background-position"
+    "background-repeat" "background-size" "baseline-shift" "baseline-source"
+    "block-ellipsis" "block-size" "block-step" "block-step-align"
+    "block-step-insert" "block-step-round" "block-step-size" "bookmark-label"
+    "bookmark-level" "bookmark-state" "border" "border-block"
+    "border-block-color" "border-block-end" "border-block-end-color"
+    "border-block-end-style" "border-block-end-width" "border-block-start"
+    "border-block-start-color" "border-block-start-style"
+    "border-block-start-width" "border-block-style" "border-block-width"
+    "border-bottom" "border-bottom-color" "border-bottom-left-radius"
+    "border-bottom-right-radius" "border-bottom-style" "border-bottom-width"
+    "border-boundary" "border-collapse" "border-color" "border-end-end-radius"
+    "border-end-start-radius" "border-image" "border-image-outset"
+    "border-image-repeat" "border-image-slice" "border-image-source"
+    "border-image-width" "border-inline" "border-inline-color"
+    "border-inline-end" "border-inline-end-color" "border-inline-end-style"
+    "border-inline-end-width" "border-inline-start" "border-inline-start-color"
+    "border-inline-start-style" "border-inline-start-width" "border-inline-style"
+    "border-inline-width" "border-left" "border-left-color" "border-left-style"
+    "border-left-width" "border-radius" "border-right" "border-right-color"
+    "border-right-style" "border-right-width" "border-spacing"
+    "border-start-end-radius" "border-start-start-radius" "border-style"
+    "border-top" "border-top-color" "border-top-left-radius"
+    "border-top-right-radius" "border-top-style" "border-top-width"
+    "border-width" "bottom" "box-decoration-break" "box-shadow" "box-sizing"
+    "box-snap" "break-after" "break-before" "break-inside" "caption-side" "caret"
+    "caret-color" "caret-shape" "chains" "clear" "clip" "clip-path" "clip-rule"
+    "color" "color-adjust" "color-interpolation-filters" "color-scheme"
+    "column-count" "column-fill" "column-gap" "column-rule" "column-rule-color"
+    "column-rule-style" "column-rule-width" "column-span" "column-width" "columns"
+    "contain" "contain-intrinsic-block-size" "contain-intrinsic-height"
+    "contain-intrinsic-inline-size" "contain-intrinsic-size"
+    "contain-intrinsic-width" "content" "content-visibility" "continue"
+    "counter-increment" "counter-reset" "counter-set" "cue" "cue-after"
+    "cue-before" "cursor" "direction" "display" "dominant-baseline" "elevation"
+    "empty-cells" "fill" "fill-break" "fill-color" "fill-image" "fill-opacity"
+    "fill-origin" "fill-position" "fill-repeat" "fill-rule" "fill-size" "filter"
+    "flex" "flex-basis" "flex-direction" "flex-flow" "flex-grow" "flex-shrink"
+    "flex-wrap" "float" "float-defer" "float-offset" "float-reference"
+    "flood-color" "flood-opacity" "flow" "flow-from" "flow-into" "font"
+    "font-family" "font-feature-settings" "font-kerning" "font-language-override"
+    "font-optical-sizing" "font-palette" "font-size" "font-size-adjust"
+    "font-stretch" "font-style" "font-synthesis" "font-synthesis-small-caps"
+    "font-synthesis-style" "font-synthesis-weight" "font-variant"
+    "font-variant-alternates" "font-variant-caps" "font-variant-east-asian"
+    "font-variant-emoji" "font-variant-ligatures" "font-variant-numeric"
+    "font-variant-position" "font-variation-settings" "font-weight"
+    "footnote-display" "footnote-policy" "forced-color-adjust" "gap"
+    "glyph-orientation-vertical" "grid" "grid-area" "grid-auto-columns"
+    "grid-auto-flow" "grid-auto-rows" "grid-column" "grid-column-end"
+    "grid-column-start" "grid-row" "grid-row-end" "grid-row-start" "grid-template"
+    "grid-template-areas" "grid-template-columns" "grid-template-rows"
+    "hanging-punctuation" "height" "hyphenate-character" "hyphenate-limit-chars"
+    "hyphenate-limit-last" "hyphenate-limit-lines" "hyphenate-limit-zone"
+    "hyphens" "image-orientation" "image-rendering" "image-resolution"
+    "initial-letter" "initial-letter-align" "initial-letter-wrap" "inline-size"
+    "inline-sizing" "input-security" "inset" "inset-block" "inset-block-end"
+    "inset-block-start" "inset-inline" "inset-inline-end" "inset-inline-start"
+    "isolation" "justify-content" "justify-items" "justify-self" "leading-trim"
+    "left" "letter-spacing" "lighting-color" "line-break" "line-clamp"
+    "line-grid" "line-height" "line-height-step" "line-padding" "line-snap"
+    "list-style" "list-style-image" "list-style-position" "list-style-type"
+    "margin" "margin-block" "margin-block-end" "margin-block-start"
+    "margin-bottom" "margin-break" "margin-inline" "margin-inline-end"
+    "margin-inline-start" "margin-left" "margin-right" "margin-top" "margin-trim"
+    "marker" "marker-end" "marker-knockout-left" "marker-knockout-right"
+    "marker-mid" "marker-pattern" "marker-segment" "marker-side" "marker-start"
+    "mask" "mask-border" "mask-border-mode" "mask-border-outset"
+    "mask-border-repeat" "mask-border-slice" "mask-border-source"
+    "mask-border-width" "mask-clip" "mask-composite" "mask-image" "mask-mode"
+    "mask-origin" "mask-position" "mask-repeat" "mask-size" "mask-type"
+    "max-block-size" "max-height" "max-inline-size" "max-lines" "max-width"
+    "min-block-size" "min-height" "min-inline-size" "min-intrinsic-sizing"
+    "min-width" "mix-blend-mode" "nav-down" "nav-left" "nav-right" "nav-up"
+    "object-fit" "object-position" "offset" "offset-anchor" "offset-distance"
+    "offset-path" "offset-position" "offset-rotate" "opacity" "order" "orphans"
+    "outline" "outline-color" "outline-offset" "outline-style" "outline-width"
+    "overflow" "overflow-anchor" "overflow-block" "overflow-clip-margin"
+    "overflow-inline" "overflow-wrap" "overflow-x" "overflow-y"
+    "overscroll-behavior" "overscroll-behavior-block" "overscroll-behavior-inline"
+    "overscroll-behavior-x" "overscroll-behavior-y" "padding" "padding-block"
+    "padding-block-end" "padding-block-start" "padding-bottom" "padding-inline"
+    "padding-inline-end" "padding-inline-start" "padding-left" "padding-right"
+    "padding-top" "page" "page-break-after" "page-break-before" "page-break-inside"
+    "pause" "pause-after" "pause-before" "perspective" "perspective-origin" "pitch"
+    "pitch-range" "place-content" "place-items" "place-self" "play-during"
+    "position" "print-color-adjust" "property-name" "quotes" "region-fragment"
+    "resize" "rest" "rest-after" "rest-before" "richness" "right" "rotate"
+    "row-gap" "ruby-align" "ruby-merge" "ruby-overhang" "ruby-position" "running"
+    "scale" "scroll-behavior" "scroll-margin" "scroll-margin-block"
+    "scroll-margin-block-end" "scroll-margin-block-start" "scroll-margin-bottom"
+    "scroll-margin-inline" "scroll-margin-inline-end" "scroll-margin-inline-start"
+    "scroll-margin-left" "scroll-margin-right" "scroll-margin-top" "scroll-padding"
+    "scroll-padding-block" "scroll-padding-block-end" "scroll-padding-block-start"
+    "scroll-padding-bottom" "scroll-padding-inline" "scroll-padding-inline-end"
+    "scroll-padding-inline-start" "scroll-padding-left" "scroll-padding-right"
+    "scroll-padding-top" "scroll-snap-align" "scroll-snap-stop" "scroll-snap-type"
+    "scrollbar-color" "scrollbar-gutter" "scrollbar-width" "shape-image-threshold"
+    "shape-inside" "shape-margin" "shape-outside" "spatial-navigation-action"
+    "spatial-navigation-contain" "spatial-navigation-function" "speak" "speak-as"
+    "speak-header" "speak-numeral" "speak-punctuation" "speech-rate" "stress"
+    "string-set" "stroke" "stroke-align" "stroke-alignment" "stroke-break"
+    "stroke-color" "stroke-dash-corner" "stroke-dash-justify" "stroke-dashadjust"
+    "stroke-dasharray" "stroke-dashcorner" "stroke-dashoffset" "stroke-image"
+    "stroke-linecap" "stroke-linejoin" "stroke-miterlimit" "stroke-opacity"
+    "stroke-origin" "stroke-position" "stroke-repeat" "stroke-size" "stroke-width"
+    "tab-size" "table-layout" "text-align" "text-align-all" "text-align-last"
+    "text-combine-upright" "text-decoration" "text-decoration-color"
+    "text-decoration-line" "text-decoration-skip" "text-decoration-skip-box"
+    "text-decoration-skip-ink" "text-decoration-skip-inset"
+    "text-decoration-skip-self" "text-decoration-skip-spaces"
+    "text-decoration-style" "text-decoration-thickness" "text-edge" "text-emphasis"
+    "text-emphasis-color" "text-emphasis-position" "text-emphasis-skip"
+    "text-emphasis-style" "text-group-align" "text-indent" "text-justify"
+    "text-orientation" "text-overflow" "text-shadow" "text-space-collapse"
+    "text-space-trim" "text-spacing" "text-transform" "text-underline-offset"
+    "text-underline-position" "text-wrap" "top" "transform" "transform-box"
+    "transform-origin" "transform-style" "transition" "transition-delay"
+    "transition-duration" "transition-property" "transition-timing-function"
+    "translate" "unicode-bidi" "user-select" "vertical-align" "visibility"
+    "voice-balance" "voice-duration" "voice-family" "voice-pitch" "voice-range"
+    "voice-rate" "voice-stress" "voice-volume" "volume" "white-space" "widows"
+    "width" "will-change" "word-boundary-detection" "word-boundary-expansion"
+    "word-break" "word-spacing" "word-wrap" "wrap-after" "wrap-before" "wrap-flow"
+    "wrap-inside" "wrap-through" "writing-mode" "z-index"
+    ;; Descriptors, not really properties, but they look like properties
+    ;; https://www.w3.org/Style/CSS/all-descriptors
+    "additive-symbols" "any-hover" "any-pointer" "ascent-override" "aspect-ratio"
+    "base-palette" "bleed" "color" "color-gamut" "color-index" "components"
+    "descent-override" "device-aspect-ratio" "device-height" "device-width"
+    "display-mode" "dynamic-range" "environment-blending" "fallback" "font-display"
+    "font-family" "font-feature-settings" "font-language-override"
+    "font-named-instance" "font-size" "font-stretch" "font-style"
+    "font-variation-settings" "font-weight" "forced-colors" "grid" "height"
+    "hover" "inherits" "initial-value" "inverted-colors" "line-gap-override"
+    "marks" "max-height" "max-width" "max-zoom" "min-height" "min-width"
+    "min-zoom" "monochrome" "negative" "orientation" "overflow-block"
+    "overflow-inline" "override-color" "pad" "pointer" "prefers-color-scheme"
+    "prefers-contrast" "prefers-reduced-data" "prefers-reduced-motion"
+    "prefers-reduced-transparency" "prefix" "range" "rendering-intent"
+    "resolution" "scan" "scripting" "shape" "size" "size-adjust" "speak-as" "src"
+    "subscript-position-override" "subscript-size-override" "suffix"
+    "superscript-position-override" "superscript-size-override" "symbols"
+    "syntax" "system" "unicode-range" "update" "user-zoom" "video-color-gamut"
+    "video-dynamic-range" "video-height" "video-resolution" "video-width"
+    "viewport-fit" "width" "zoom"))
+
+(define %prefixed-properties
+  (apply append
+         %css-properties
+         (map
+           (lambda (prefix)
+             (map
+               (lambda (property)
+                 (string-append prefix property))
+               %css-properties))
+           %css-vendor-prefixes)))
+
+(define %css-keyword-values
+  '("inherit" "auto" "initial" "unset"
+    ;; https://www.w3.org/TR/css-color-3
+    "transparent" "aliceblue" "antiquewhite" "aqua" "aquamarine" "azure" "beige"
+    "bisque" "black" "blanchedalmond" "blue" "blueviolet" "brown" "burlywood"
+    "cadetblue" "chartreuse" "chocolate" "coral" "cornflowerblue" "cornsilk"
+    "crimson" "cyan" "darkblue" "darkcyan" "darkgoldenrod" "darkgray" "darkgreen"
+    "darkgrey" "darkkhaki" "darkmagenta" "darkolivegreen" "darkorange" "darkorchid"
+    "darkred" "darksalmon" "darkseagreen" "darkslateblue" "darkslategray"
+    "darkslategrey" "darkturquoise" "darkviolet" "deeppink" "deepskyblue"
+    "dimgray" "dimgrey" "dodgerblue" "firebrick" "floralwhite" "forestgreen"
+    "fuchsia" "gainsboro" "ghostwhite" "gold" "goldenrod" "gray" "green"
+    "greenyellow" "grey" "honeydew" "hotpink" "indianred" "indigo" "ivory"
+    "khaki" "lavender" "lavenderblush" "lawngreen" "lemonchiffon" "lightblue"
+    "lightcoral" "lightcyan" "lightgoldenrodyellow" "lightgray" "lightgreen"
+    "lightgrey" "lightpink" "lightsalmon" "lightseagreen" "lightskyblue"
+    "lightslategray" "lightslategrey" "lightsteelblue" "lightyellow" "lime"
+    "limegreen" "linen" "magenta" "maroon" "mediumaquamarine" "mediumblue"
+    "mediumorchid" "mediumpurple" "mediumseagreen" "mediumslateblue"
+    "mediumspringgreen" "mediumturquoise" "mediumvioletred" "midnightblue"
+    "mintcream" "mistyrose" "moccasin" "navajowhite" "navy" "oldlace" "olive"
+    "olivedrab" "orange" "orangered" "orchid" "palegoldenrod" "palegreen"
+    "paleturquoise" "palevioletred" "papayawhip" "peachpuff" "peru" "pink"
+    "plum" "powderblue" "purple" "red" "rosybrown" "royalblue" "saddlebrown"
+    "salmon" "sandybrown" "seagreen" "seashell" "sienna" "silver" "skyblue"
+    "slateblue" "slategray" "slategrey" "snow" "springgreen" "steelblue"
+    "tan" "teal" "thistle" "tomato" "turquoise" "violet" "wheat" "white"
+    "whitesmoke" "yellow" "yellowgreen" "currentColor"
+    ;; deprecated in css 3
+    "ActiveBorder" "ActiveCaption" "AppWorkspace" "Background" "ButtonFace"
+    "ButtonHighlight" "ButtonShadow" "ButtonText" "CaptionText" "GrayText"
+    "Highlight" "HighlightText" "InactiveBorder" "InactiveCaption" "InactiveCaptionText"
+    "InfoBackground" "InfoText" "Menu" "MenuText" "Scrollbar" "ThreeDDarkShadow"
+    "ThreeDFace" "ThreeDHighlight" "ThreeDLightShadow" "ThreeDShadow" "Window"
+    "WindowFrame" "WindowText"
+    ;; https://www.w3.org/TR/css-backgrounds-3
+    "repeat" "repeat-x" "repeat-y" "space" "round" "no-repeat" "scroll" "fixed"
+    "local" "left" "center" "right" "top" "bottom" "border-box" "content-box"
+    "padding-box" "contain" "cover"
+    "none" "hidden" "dotted" "dashed" "solid" "double" "groove" "ridge" "inset"
+    "outset"
+    ;; https://www.w3.org/TR/css-images-3
+    "fill" "scale-down" "from-image" "flip" "smooth" "high-quality" "crisp-edges"
+    "pixelated"
+    ;; https://www.w3.org/TR/css-fonts-3
+    "normal" "bold" "bolder" "lighter" "ultra-condensed" "extra-condensed"
+    "condensed" "semi-condensed" "semi-expanded" "expanded" "extra-expanded"
+    "ultra-expanded" "italic" "oblique" "xx-small" "x-small" "small" "medium"
+    "large" "x-large" "xx-large" "larger" "smaller" "small-caps" "caption"
+    "icon" "menu" "message-box" "small-caption" "status-bar"
+    ;; https://www.w3.org/TR/css-writing-modes-3
+    "ltr" "rtl" "embed" "isolate" "bidi-override" "isolate-override" "plaintext"
+    "horizontal-tb" "vertical-rl" "vertical-lr" "mixed" "upright" "sideways"
+    ;; https://www.w3.org/TR/css-multicol-1
+    "balance" "balance-all"
+    ;; https://www.w3.org/TR/css-flexbox-1
+    "row" "row-reverse" "column" "column-reverse" "nowrap" "wrap" "wrap-reverse"
+    "content" "flex-start" "flex-end" "center" "space-between" "space-around"
+    "baseline" "stretch"
+    ;; https://www.w3.org/TR/css-ui-3
+    "content-box" "border-box" "both" "horizontal" "vertical" "clip" "ellipsis"
+    "default" "context-menu" "help" "pointer" "progress" "wait" "cell"
+    "crosshair" "text" "vertical-text" "alias" "copy" "move" "no-drop"
+    "not-allowed" "grab" "grabbing" "e-resize" "n-resize" "ne-resize"
+    "nw-resize" "s-resize" "se-resize" "sw-resize" "w-resize" "ew-resize"
+    "ns-resize" "nesw-resize" "nwse-resize" "col-resize" "row-resize"
+    "all-scroll" "zoom-in" "zoom-out"
+    ;; https://www.w3.org/TR/css-contain-1
+    "strict" "content" "size" "layout" "paint"
+    ;; https://www.w3.org/TR/css-transforms-1
+    "content-box" "border-box" "fill-box" "stroke-box" "view-box"
+    ;; https://www.w3.org/TR/compositing-1
+    "multiply" "screen" "overlay" "darken" "lighten" "color-dodge" "color-burn"
+    "hard-light" "soft-light" "difference" "exclusion" "hue" "saturation" "color"
+    "luminosity" "isolate"
+    ;; https://www.w3.org/TR/css-easing-1
+    "linear" "ease" "ease-in" "ease-out" "ease-in-out" "step-start" "step-end"
+    ;; ??
+    "inline" "flex" "inline-block" "block" "table" "table-row" "table-cell"
+    "thin"
+    "relative" "absolute"
+    "start" "left" "right" "center" "justify"
+    ))
+
+(define %css-units
+  '("dpi" "dpcm" "dppx" "%" "em" "ex" "ch" "rem" "vw" "vh" "vmin" "vmax" "cm"
+    "mm" "Q" "in" "pt" "pc" "px" "deg" "rad" "grad" "turn" "s" "ms" "Hz" "kHz"))
+
+(define lex-escape
+  (lex-all (lex-string "\\")
+           (lex-any
+             (lex-char-set (string->char-set "0123456789abcdefABCDEF") #:max 6)
+             (lex-char (char-set-complement (char-set #\newline))))))
+
+(define lex-color
+  (lex-group
+    (lex-all (lex-string "#")
+             (lex-char-set (string->char-set "0123456789abcdefABCDEF")))))
+
+(define ident-char-set
+  (char-set-union
+    (char-set #\_)
+    char-set:letter))
+(define ident-rest-char-set
+  (char-set-union
+    (char-set #\_ #\-)
+    char-set:letter+digit))
+
+(define lex-ident
+  (lex-group
+    (lex-all
+      (lex-any
+        (lex-string "--")
+        (lex-all
+          (lex-maybe (lex-string "-"))
+          (lex-any
+            lex-escape
+            (lex-char ident-char-set))))
+      (lex-zero-or-more
+        (lex-any
+          lex-escape
+          (lex-char-set ident-rest-char-set))))))
+
+(define lex-double-string
+  (lex-all
+    (lex-string "\"")
+    (lex-zero-or-more
+      (lex-any
+        (lex-char-set (char-set-complement (char-set #\\ #\" #\newline)))
+        lex-escape
+        (lex-string "\\\n")))
+    (lex-string "\"")))
+
+(define lex-single-string
+  (lex-all
+    (lex-string "'")
+    (lex-zero-or-more
+      (lex-any
+        (lex-char-set (char-set-complement (char-set #\\ #\' #\newline)))
+        lex-escape
+        (lex-string "\\\n")))
+    (lex-string "'")))
+
+(define lex-number
+  (lex-group
+    (lex-all
+      (lex-maybe
+        (lex-any (lex-string "-") (lex-string "+")))
+      (lex-char-set char-set:digit)
+      (lex-maybe (lex-string "."))
+      (lex-maybe (lex-char-set char-set:digit))
+      (lex-maybe
+        (lex-all
+          (lex-any (lex-string "e") (lex-string "E"))
+          (lex-maybe
+            (lex-any (lex-string "-") (lex-string "+")))
+          (lex-char-set char-set:digit))))))
+
+(define lex-ws
+  (lex-any (lex-tag 'comment (lex-delimited "/*" #:until "*/"))
+           (lex-char-set char-set:whitespace)))
+
+(define lex-token
+  (lex-any
+    (lex-tag 'comment (lex-delimited "/*" #:until "*/"))
+    (lex-char-set char-set:whitespace)
+    (lex-tag 'string (lex-group lex-double-string))
+    (lex-tag 'string (lex-group lex-single-string))
+    (lex-tag 'id (lex-group (lex-all (lex-string "#")
+                                     lex-ident)))
+    (lex-tag 'open (lex-string "("))
+    (lex-tag 'close (lex-string ")"))
+    (lex-tag 'open (lex-string "{"))
+    (lex-tag 'close (lex-string "}"))
+    (lex-tag 'open (lex-string "["))
+    (lex-tag 'close (lex-string "]"))
+    (lex-tag 'number (lex-group
+                       (lex-all
+                         lex-number
+                         (lex-maybe
+                           (lex-any
+                             (lex-filter (lambda (str)
+                                           (any (cut string=? <> str)
+                                                %css-units))
+                                         lex-ident)
+                             (lex-string "%"))))))
+    (lex-tag 'comma (lex-string ","))
+    (lex-tag 'cdc (lex-string "-->"))
+    (lex-tag 'colon (lex-string ":"))
+    (lex-tag 'semi (lex-string ";"))
+    (lex-tag 'cdo (lex-string "<!--"))
+    (lex-tag 'keyword
+              (lex-group
+                (lex-all
+                  (lex-string "@")
+                  lex-ident)))
+    (lex-tag 'ident lex-ident)
+    (lex-char char-set:full)))
+
+(define (lex-css-single)
+  (define function-lexer
+    (lex-all
+      (lex-any
+        (lex-tag 'builtin
+                 (lex-filter (lambda (str)
+                               (any (cut string=? <> str)
+                                    %css-functions))
+                             lex-ident))
+        (lex-tag 'function lex-ident))
+      (lex-tag 'open (lex-string "("))
+      (lex-consume-until (lex-tag 'close (lex-string ")"))
+        (lex-component-value 'function))))
+  (define (lex-function tokens cursor)
+    (function-lexer tokens cursor))
+
+  (define (lex-definition position)
+    (lex-all
+      (lex-any
+        (lex-tag 'builtin-property
+                 (lex-filter (lambda (str)
+                               (any (cut string=? <> str)
+                                    %prefixed-properties))
+                             lex-ident))
+        (lex-tag 'property lex-ident))
+      (lex-zero-or-more lex-ws)
+      (lex-string ":")
+      (lex-zero-or-more lex-ws)
+      (lex-consume-until (lex-any
+                           (lex-tag 'comma (lex-string ";"))
+                           (lex-peek (lex-string (match position
+                                                   ('curly "}")
+                                                   ('rule "}")
+                                                   ('paren ")")))))
+        (lex-component-value 'value))))
+
+  (define (lex-component-value position)
+    (lex-any
+      lex-ws
+      lex-block
+      lex-function
+      (match position
+        ('curly
+         (lex-any
+           lex-rule
+           (lex-definition position)))
+        ((or 'rule 'paren)
+         (lex-definition position))
+        ('prelude
+         (lex-any
+                    (lex-tag 'class (lex-group (lex-all (lex-string ".") lex-ident)))
+                    (lex-all
+                      (lex-tag 'selector (lex-group (lex-all (lex-string ":") lex-ident)))
+                      (lex-maybe
+                        (lex-all
+                          (lex-tag 'open (lex-string "("))
+                          (lex-consume-until (lex-tag 'close (lex-string ")"))
+                            lex-prelude-component-value))))
+                    (lex-tag 'prelude lex-ident)
+                    (lex-string ">")
+                    (lex-string "*")))
+        ('value (lex-any
+                  (lex-tag 'color lex-color)
+                  (lex-tag 'important (lex-string "!important"))
+                  (lex-tag 'keyword
+                           (lex-filter (lambda (str)
+                                         (any (cut string=? <> str)
+                                              %css-keyword-values))
+                                       lex-ident))))
+        ;; function, square, paren
+        (_ lex-fail))
+      lex-token))
+  (define (lex-prelude-component-value tokens cursor)
+    ((lex-component-value 'prelude) tokens cursor))
+
+  (define rule-block-lexer
+    (lex-all
+      (lex-tag 'open (lex-string "{"))
+      (lex-consume-until (lex-tag 'close (lex-string "}"))
+        (lex-component-value 'rule))))
+  (define (lex-rule-block tokens cursor)
+    (rule-block-lexer tokens cursor))
+
+  (define curly-block-lexer
+    (lex-all
+      (lex-tag 'open (lex-string "{"))
+      (lex-consume-until (lex-tag 'close (lex-string "}"))
+        (lex-component-value 'curly))))
+  (define (lex-curly-block tokens cursor)
+    (curly-block-lexer tokens cursor))
+
+  (define square-block-lexer
+    (lex-all
+      (lex-tag 'open (lex-string "["))
+      (lex-consume-until (lex-tag 'close (lex-string "]"))
+        (lex-component-value 'square))))
+  (define (lex-square-block tokens cursor)
+    (square-block-lexer tokens cursor))
+
+  (define par-block-lexer
+    (lex-all
+      (lex-tag 'open (lex-string "("))
+      (lex-consume-until (lex-tag 'close (lex-string ")"))
+        (lex-component-value 'paren))))
+  (define (lex-par-block tokens cursor)
+    (par-block-lexer tokens cursor))
+
+  (define block-lexer
+    (lex-any
+      lex-curly-block
+      lex-square-block
+      lex-par-block))
+  (define (lex-block tokens cursor)
+    (block-lexer tokens cursor))
+
+  (define at-rule-lexer
+    (lex-all (lex-tag 'keyword (lex-group (lex-all (lex-string "@") lex-ident)))
+             (lex-consume-until
+               (lex-any (lex-tag 'semi (lex-string ";"))
+                        lex-curly-block)
+               (lex-any
+                 lex-block
+                 lex-at-rule
+                 lex-token))))
+  (define (lex-at-rule tokens cursor)
+    (at-rule-lexer tokens cursor))
+
+  (define rule-lexer
+    (lex-consume-until
+      lex-rule-block
+      (lex-component-value 'prelude)))
+  (define (lex-rule tokens cursor)
+    (rule-lexer tokens cursor))
+
+  (lex-any
+    lex-ws
+    lex-at-rule
+    lex-rule))
+
+(define lex-css
+  (lex-consume (lex-css-single)))
diff --git a/syntax-highlight/lexers.scm b/syntax-highlight/lexers.scm
index 0591da2..4367c82 100644
--- a/syntax-highlight/lexers.scm
+++ b/syntax-highlight/lexers.scm
@@ -63,10 +63,13 @@
             lex-maybe
             lex-regexp
             lex-string
+            lex-char
             lex-char-set
             lex-whitespace
             lex-delimited
-            lex-tag))
+            lex-tag
+            lex-group
+            lex-peek))
 
 (define (string-prefix?* s1 s2 start-s2)
   (string-prefix? s1 s2 0 (string-length s1) start-s2))
@@ -300,7 +303,7 @@ STR."
                 (move-cursor-by cursor (string-length str)))
         (fail))))
 
-(define (lex-char-set char-set)
+(define* (lex-char-set char-set #:key (min 1) (max #f))
   "Return a lexer that succeeds with the nonempty input prefix that
 matches CHAR-SET, or fails if the first input character does not
 belong to CHAR-SET."
@@ -308,7 +311,7 @@ belong to CHAR-SET."
     (let ((len (string-length str)))
       (let loop ((index start))
         (cond
-         ((>= index len)
+         ((or (>= index len) (and max (>= (- index start) max)))
           (substring str start len))
          ((char-set-contains? char-set (string-ref str index))
           (loop (1+ index)))
@@ -316,11 +319,22 @@ belong to CHAR-SET."
           (substring str start index))))))
 
   (lambda (tokens cursor)
-    (match (char-set-substring (cursor-text cursor) (cursor-position cursor))
-      ("" (fail))
-      (str
-       (values (token-add tokens str)
-               (move-cursor-by cursor (string-length str)))))))
+    (let ((str (char-set-substring (cursor-text cursor) (cursor-position cursor))))
+      (cond
+        ((equal? str "") (fail))
+        ((< (string-length str) min) (fail))
+        (else
+         (values (token-add tokens str)
+                 (move-cursor-by cursor (string-length str))))))))
+
+(define (lex-char char-set)
+  "Lex exactly one character in the given CHAR-SET."
+  (lambda (tokens cursor)
+    (let ((chr (string-ref (cursor-text cursor) (cursor-position cursor))))
+      (if (char-set-contains? char-set chr)
+          (values (token-add tokens (string chr))
+                  (move-cursor-by cursor 1))
+          (fail)))))
 
 (define lex-whitespace
   (lex-char-set char-set:whitespace))
@@ -370,3 +384,22 @@ itself."
                              (list tag (token-peek result)))
                   remainder)
           (fail)))))
+
+(define (lex-group lexer)
+  "Group the elements returned by LEXER under a single token.  LEXER must return
+a list of strings, with no tags."
+  (lambda (tokens cursor)
+    (let-values (((result remainder) (lexer empty-tokens cursor)))
+      (if result
+          (values (token-add tokens (apply string-append (tokens->list result)))
+                  remainder)
+          (fail)))))
+
+(define (lex-peek lexer)
+  "Runs a lexer on the rest of the string, but does not advance the token.  Fails
+if LEXER failed, succeeds otherwise"
+  (lambda (tokens cursor)
+    (let-values (((result remainder) (lexer empty-tokens cursor)))
+      (if result
+          (values tokens cursor)
+          (fail)))))