support by and idx

src/util/_impl/_bsearch_impl.scad

@@ -1,7 +1,20 @@
 use <util/_impl/_vt_default_comparator.scad>;
 
-function _binary_search(sorted, elem, low, upper) =
+function _binary_search_by(sorted, elem, low, upper, i) =
     low > upper ? -1 :
     let(mid = floor((low + upper) / 2))
-    lessThan(sorted[mid], elem) ? _binary_search(sorted, elem, mid + 1, upper) :
+    sorted[mid][i] < elem[i] ? _binary_search_by(sorted, elem, mid + 1, upper, i) :
-    greaterThan(sorted[mid], elem) ? _binary_search(sorted, elem, low, mid - 1) : mid;
+    sorted[mid][i] > elem[i] ? _binary_search_by(sorted, elem, low, mid - 1, i) : mid;
+
+function _bsearch_vt(sorted, elem, low, upper) =
+    low > upper ? -1 :
+    let(mid = floor((low + upper) / 2))
+    lessThan(sorted[mid], elem) ? _bsearch_vt(sorted, elem, mid + 1, upper) :
+    greaterThan(sorted[mid], elem) ? _bsearch_vt(sorted, elem, low, mid - 1) : mid;
+
+function _bsearch_by(sorted, elem, by, idx) =
+    let(
+        dict = [["x", 0], ["y", 1], ["z", 2], ["i", idx]],
+        i = dict[search(by == "idx" ? "i" : by, dict)[0]][1]
+    )
+    _binary_search_by(sorted, elem, 0, len(sorted) - 1, i);

src/util/bsearch.scad

@@ -1,4 +1,5 @@
 use <util/_impl/_bsearch_impl.scad>;
 
-// for example, `sorted` is by zyx
+function bsearch(sorted, elem, by = "idx", idx = 0) = 
-function bsearch(sorted, elem) = _binary_search(sorted, elem, 0, len(sorted) - 1);
+    by == "vt" ? _bsearch_vt(sorted, elem, 0, len(sorted) - 1) : // for example, `sorted` is by zyx
+                 _bsearch_by(sorted, elem, by, idx);

src/util/has.scad

@@ -1,5 +1,5 @@
 use <util/bsearch.scad>;
 
 function has(lt, elem, sorted = false) = 
-    sorted ? bsearch(lt, elem) != -1 :
+    sorted ? bsearch(lt, elem, by = "vt") != -1 :
              search([elem], lt) != [[]];