--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/.cms/lib/codemirror/src/model/change_measurement.js	Fri Oct 11 22:40:23 2024 +0000
@@ -0,0 +1,61 @@
+import { cmp, Pos } from "../line/pos.js"
+import { lst } from "../util/misc.js"
+
+import { normalizeSelection, Range, Selection } from "./selection.js"
+
+// Compute the position of the end of a change (its 'to' property
+// refers to the pre-change end).
+export function changeEnd(change) {
+  if (!change.text) return change.to
+  return Pos(change.from.line + change.text.length - 1,
+             lst(change.text).length + (change.text.length == 1 ? change.from.ch : 0))
+}
+
+// Adjust a position to refer to the post-change position of the
+// same text, or the end of the change if the change covers it.
+function adjustForChange(pos, change) {
+  if (cmp(pos, change.from) < 0) return pos
+  if (cmp(pos, change.to) <= 0) return changeEnd(change)
+
+  let line = pos.line + change.text.length - (change.to.line - change.from.line) - 1, ch = pos.ch
+  if (pos.line == change.to.line) ch += changeEnd(change).ch - change.to.ch
+  return Pos(line, ch)
+}
+
+export function computeSelAfterChange(doc, change) {
+  let out = []
+  for (let i = 0; i < doc.sel.ranges.length; i++) {
+    let range = doc.sel.ranges[i]
+    out.push(new Range(adjustForChange(range.anchor, change),
+                       adjustForChange(range.head, change)))
+  }
+  return normalizeSelection(doc.cm, out, doc.sel.primIndex)
+}
+
+function offsetPos(pos, old, nw) {
+  if (pos.line == old.line)
+    return Pos(nw.line, pos.ch - old.ch + nw.ch)
+  else
+    return Pos(nw.line + (pos.line - old.line), pos.ch)
+}
+
+// Used by replaceSelections to allow moving the selection to the
+// start or around the replaced test. Hint may be "start" or "around".
+export function computeReplacedSel(doc, changes, hint) {
+  let out = []
+  let oldPrev = Pos(doc.first, 0), newPrev = oldPrev
+  for (let i = 0; i < changes.length; i++) {
+    let change = changes[i]
+    let from = offsetPos(change.from, oldPrev, newPrev)
+    let to = offsetPos(changeEnd(change), oldPrev, newPrev)
+    oldPrev = change.to
+    newPrev = to
+    if (hint == "around") {
+      let range = doc.sel.ranges[i], inv = cmp(range.head, range.anchor) < 0
+      out[i] = new Range(inv ? to : from, inv ? from : to)
+    } else {
+      out[i] = new Range(from, from)
+    }
+  }
+  return new Selection(out, doc.sel.primIndex)
+}