From 44e78679e898e70ee18b0a7c73897384379683bb Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Fri, 27 Mar 2020 13:53:07 +0800
Subject: [PATCH] add assoc

---
 src/experimental/_impl/_assoc_impl.scad | 14 ++++++++++++++
 src/experimental/assoc.scad             |  9 +++++++++
 2 files changed, 23 insertions(+)
 create mode 100644 src/experimental/_impl/_assoc_impl.scad
 create mode 100644 src/experimental/assoc.scad

diff --git a/src/experimental/_impl/_assoc_impl.scad b/src/experimental/_impl/_assoc_impl.scad
new file mode 100644
index 00000000..705367f6
--- /dev/null
+++ b/src/experimental/_impl/_assoc_impl.scad
@@ -0,0 +1,14 @@
+use <util/slice.scad>;
+
+function _assoc_get(array, key) = 
+    let(idx = search([key], array)[0])
+    array[idx][1];
+
+function _assoc_put(array, key, value) =
+    let(idx = search([key], array)[0])
+    idx == [] ? concat(array, [[key, value]]) : 
+                concat(slice(array, 0, idx), [[key, value]], slice(array, idx + 1));
+
+function _assoc_remove(array, key) =
+    let(idx = search([key], array)[0])
+    idx == [] ? array : concat(slice(array, 0, idx), slice(array, idx + 1));
\ No newline at end of file
diff --git a/src/experimental/assoc.scad b/src/experimental/assoc.scad
new file mode 100644
index 00000000..04b6cc88
--- /dev/null
+++ b/src/experimental/assoc.scad
@@ -0,0 +1,9 @@
+use <experimental/_impl/_assoc_impl.scad>;
+
+// treat an associative array as a dictionary.
+
+function assoc(array, cmd, key, value) =
+    is_undef(array) ? [] :
+    cmd == "put" ? _assoc_put(array, key, value) :
+    cmd == "get" ? _assoc_get(array, key) :
+    cmd == "remove" ? _assoc_remove(array, key) : assert("Uknown command");
\ No newline at end of file