From 0007f1286c943b9d4817aa4ebbed818babf5ccfb Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Sun, 15 May 2022 11:47:44 -0400
Subject: [PATCH] bug fixes

---
 strings.scad             | 14 ++++++++++++++
 tutorials/Attachments.md |  8 ++++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/strings.scad b/strings.scad
index b323364..3682779 100644
--- a/strings.scad
+++ b/strings.scad
@@ -332,6 +332,20 @@ function upcase(str) =
     str_join([for(char=str) let(code=ord(char)) code>=97 && code<=122 ? chr(code-32) : char]);
 
 
+// Section: Random strings
+
+// Function: rand_str()
+// Usage:
+//    str = rand_str(n, [charset], [seed]);
+// Description:
+//    Produce a random string of length `n`.  If you give a string `charset` then the
+//    characters of the random string are drawn from that list, weighted by the number
+//    of times each character appears in the list.  If you do not give a character set
+//    then the string is generated with characters ranging from 0 to z (based on
+//    character code).  
+function rand_str(n, charset, seed) = 
+  is_undef(charset)? str_join([for(c=rand_int(48,122,n,seed)) chr(c)])
+                   : str_join([for(i=rand_int(0,len(charset)-1,n,seed)) charset[i]]);
 
 
 
diff --git a/tutorials/Attachments.md b/tutorials/Attachments.md
index 9719c86..b42cd51 100644
--- a/tutorials/Attachments.md
+++ b/tutorials/Attachments.md
@@ -445,14 +445,14 @@ tag("keep")cube(100, center=true)
 ```
 
 
-If you need to mark multiple children with a tag, you can use the `tags()` module.
+If you need to mark multiple children with a tag, you can use the `tag()` module.
 
 ```openscad-3D
 include <BOSL2/std.scad>
 diff("hole")
 cube(100, center=true)
     attach([FRONT,TOP], overlap=20)
-        tags("hole") {
+        tag("hole") {
             cylinder(h=20.1, d1=0, d2=95);
             down(10) cylinder(h=30, d=30);
         }
@@ -475,14 +475,14 @@ Some notable non-attachable modules are `text()`, `linear_extrude()`, `rotate_ex
 `intersection()`, `offset()`, `hull()`, and `minkowski()`.
 
 To allow you to use tags-based operations with non-attachable shapes, you can wrap them with the
-`force_tags()` module to specify their tags.  For example:
+`force_tag()` module to specify their tags.  For example:
 
 ```openscad-3D
 include <BOSL2/std.scad>
 diff("hole")
 cuboid(50)
   attach(TOP)
-    force_tags("hole")
+    force_tag("hole")
       rotate_extrude()
         right(15)
           square(10,center=true);