ported rivet to typst

src/structure.typ

@@ -0,0 +1,54 @@
+#import "range.typ"
+#import "util.typ"
+
+#let make(
+  name,
+  bits,
+  ranges,
+  start: 0
+) = {
+  return (
+    name: name,
+    bits: bits,
+    ranges: ranges,
+    start: start
+  )
+}
+
+#let load(id, data) = {
+  let struct = (id: id)
+  let ranges = (:)
+
+  for (range-span, range-data) in data.ranges {
+    let (start, end) = range.parse-span(str(range-span))
+    ranges.insert(
+      range.key(start, end),
+      range.load(start, end, range-data)
+    )
+  }
+
+  for range_ in ranges.values() {
+    if range_.values != none and range_.depends-on != none {
+      let depends-key = range.key(..range_.depends-on)
+      let depends-range = ranges.at(depends-key)
+      let bits = range.bits(depends-range)
+      let values = (:)
+      for (v, d) in range_.values {
+        v = util.z-fill(str(int(v)), bits)
+        values.insert(v, d)
+      }
+    }
+  }
+
+  return make(
+    id,
+    int(data.bits),
+    ranges,
+    start: data.at("start", default: 0)
+  )
+}
+
+#let get-sorted-ranges(struct) = {
+  let ranges = struct.ranges.values()
+  return ranges.sorted(key: r => r.end)
+}