added range names and bit ranks

src/render/structure.typ

@@ -1,5 +1,7 @@
 #import "../cetz.typ": draw
 
+#let BACKGROUND-LAYER = -1
+
 #let draw-track(config, schema, struct, pos) = draw.group(name: "track", {
   let colors = schema.at("colors", default: (:))
   let total-width = struct.bits * config.bit-width
@@ -28,6 +30,7 @@
       let col = bit-colors.at(str(rank), default: config.background)
 
       // Background color
+      draw.on-layer(BACKGROUND-LAYER, {
         draw.rect(
           (rel: (j * config.bit-width, 0), to: pos),
           (rel: (config.bit-width, config.bit-height)),
@@ -35,6 +38,7 @@
           stroke: none,
           name: str(rank)
         )
+      })
 
       if j != struct.bits - 1 {
         let top = str(rank) + ".north-east"
@@ -73,6 +77,33 @@
   )
 
   // Names
+  for r in struct.ranges.values() {
+    let i0 = r.start
+    let i1 = r.end
+    if not config.ltr-bits {
+      (i0, i1) = (i1, i0)
+    }
+    let start = "bits." + str(i0) + ".north-west"
+    let end = "bits." + str(i1) + ".south-east"
+    draw.content(
+      (start, 50%, end),
+      r.name
+    )
+  }
+
+  let indices = if config.all-bit-i {
+    range(struct.start, struct.start + struct.bits)
+  } else {
+    struct.ranges.values().map(r => (r.start, r.end)).flatten().dedup()
+  }
+  for i in indices {
+    draw.content(
+      "bits." + str(i) + ".north",
+      anchor: "south",
+      str(i),
+      padding: 4pt  // TODO: Maybe configurable
+    )
+  }
 })
 
 #let render(