From 1f741d63e5c1c4c3eef29b7e681f0fbf8166c439 Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Sat, 14 Mar 2020 16:20:19 +0800
Subject: [PATCH] support by and idx

---
 src/util/_impl/_bsearch_impl.scad | 19 ++++++++++++++++---
 src/util/bsearch.scad             |  5 +++--
 src/util/has.scad                 |  2 +-
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/util/_impl/_bsearch_impl.scad b/src/util/_impl/_bsearch_impl.scad
index 7e1e6d79..bb5ffa6c 100644
--- a/src/util/_impl/_bsearch_impl.scad
+++ b/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) :
-    greaterThan(sorted[mid], elem) ? _binary_search(sorted, elem, low, mid - 1) : mid;
\ No newline at end of file
+    sorted[mid][i] < elem[i] ? _binary_search_by(sorted, elem, mid + 1, upper, i) :
+    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);
\ No newline at end of file
diff --git a/src/util/bsearch.scad b/src/util/bsearch.scad
index 893210bd..45f9b809 100644
--- a/src/util/bsearch.scad
+++ b/src/util/bsearch.scad
@@ -1,4 +1,5 @@
 use <util/_impl/_bsearch_impl.scad>;
 
-// for example, `sorted` is by zyx
-function bsearch(sorted, elem) = _binary_search(sorted, elem, 0, len(sorted) - 1);
\ No newline at end of file
+function bsearch(sorted, elem, by = "idx", idx = 0) = 
+    by == "vt" ? _bsearch_vt(sorted, elem, 0, len(sorted) - 1) : // for example, `sorted` is by zyx
+                 _bsearch_by(sorted, elem, by, idx);
\ No newline at end of file
diff --git a/src/util/has.scad b/src/util/has.scad
index 5accf856..e66c2d57 100644
--- a/src/util/has.scad
+++ b/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) != [[]];
\ No newline at end of file