str_join -> chr when possible, doc fixes in masks.scad

comparisons.scad

@@ -455,7 +455,7 @@ function deduplicate(list, closed=false, eps=_EPSILON) =
         l = len(list),
         end = l-(closed?0:1)
     )
-    is_string(list) ? str_join([for (i=[0:1:l-1]) if (i==end || list[i] != list[(i+1)%l]) list[i]]) :
+    is_string(list) ? chr([for (i=[0:1:l-1]) if (i==end || list[i] != list[(i+1)%l]) ord(list[i]])) :
     eps==0 ? [for (i=[0:1:l-1]) if (i==end || list[i] != list[(i+1)%l]) list[i]] :
     [for (i=[0:1:l-1]) if (i==end || !approx(list[i], list[(i+1)%l], eps)) list[i]];
 
@@ -580,7 +580,7 @@ function list_unwrap(list, eps=_EPSILON) =
 //   sorted = unique([true,2,"xba",[1,0],true,[0,0],3,"a",[0,0],2]); // Returns: [true,2,3,"a","xba",[0,0],[1,0]]
 function unique(list) =
     assert(is_list(list)||is_string(list), "Invalid input." )
-    is_string(list)? str_join(unique([for (x = list) x])) :
+    is_string(list)? chr(unique([for (x = list) ord(x)])) :
     len(list)<=1? list : 
     is_homogeneous(list,1) && ! is_list(list[0])
     ?   _unique_sort(list)
@@ -840,7 +840,7 @@ function _indexed_sort(arrind) =
 //   sorted3 = sort(l3); // Returns: [20,[3,1],[3,9],[4],[4,0],[7],[8]]
 function sort(list, idx=undef) = 
     assert(is_list(list)||is_string(list), "Invalid input." )
-    is_string(list)? str_join(sort([for (x = list) x],idx)) :
+    is_string(list)? chr(sort([for (x = list) ord(x)])) :
     !is_list(list) || len(list)<=1 ? list :
     is_homogeneous(list,1)
     ?   let(size = list_shape(list[0]))

linalg.scad

@@ -126,9 +126,9 @@ function is_rotation(A,dim,centered=false) =
 //    eps = numbers smaller than this display as zero.  Default: 1e-9
 function echo_matrix(M,description,sig=4,sep=1,eps=1e-9) =
   let(
-      horiz_line = chr(8213),
+      horiz_line = 8213,
       matstr = _format_matrix(M,sig=sig,sep=sep,eps=eps),
-      separator = str_join(repeat(horiz_line,10)),
+      separator = chf(repeat(horiz_line,10)),
       dummy=echo(str(separator,is_def(description) ? str("  ",description) : ""))
             [for(row=matstr) echo(row)]
   )

masks.scad

@@ -1185,7 +1185,8 @@ module face_profile(faces=[], r, d, excess=0.01, convexity=10) {
 // Usage:
 //   PARENT() edge_profile([edges], [except], [convexity]) CHILDREN;
 // Description:
-//   Takes a 2D mask shape and attaches it to the selected edges, with the appropriate orientation and
+//   Takes a 2D mask shape and attaches it to the selected edges of a cuboid, prismoid or cone, with the
+//   appropriate orientation and
 //   extruded length to be `diff()`ed away, to give the edge a matching profile.  If no tag is set
 //   then `edge_profile` sets the tag for children to "remove" so that it works with the default {{diff()}} tag.
 //   For details on specifying the edges to mask see [Specifying Edges](attachments.scad#subsection-specifying-edges).
@@ -1223,7 +1224,8 @@ module face_profile(faces=[], r, d, excess=0.01, convexity=10) {
 
 module edge_profile(edges=EDGES_ALL, except=[], excess=0.01, convexity=10) {
     req_children($children);
-    check1 = assert($parent_geom != undef, "\nNo object to attach to!");
+    check1 = assert($parent_geom != undef, "\nNo object to attach to!")
+             assert(in_list($parent_geom[0],["conoid","prismoid"]), "Parent must be a cyl, cuboid or prismoid");
     conoid = $parent_geom[0] == "conoid";
     edges = !conoid? _edges(edges, except=except) :
         edges==EDGES_ALL? [TOP,BOT] :
@@ -1552,9 +1554,14 @@ module edge_profile_asym(
         [for (i=[0:2]) if (abs(e1[i])==1 && e1[i]==e2[i]) -e1[i] else 0];
 
     req_children($children);
+
+    is_cuboid = is_def($parent_geom) && $parent_geom[0]=="prismoid"
+                  && point2d($parent_geom[1])==$parent_geom[2]
+                  && $parent_geom[3]==[0,0];
     check1 = assert($parent_geom != undef, "\nNo object to attach to!")
-        assert(in_list(corner_type, ["none", "round", "chamfer", "sharp"]))
-        assert(is_bool(flip));
+             assert(is_cuboid, "Parent must be a cuboid")      
+             assert(in_list(corner_type, ["none", "round", "chamfer", "sharp"]))
+             assert(is_bool(flip));
     edges = _edges(edges, except=except);
     vecs = [
         for (i = [0:3], axis=[0:2])
@@ -2164,7 +2171,6 @@ module polygon_edge_mask(mask, length, height, l, h, scale=1, anchor="origin", a
   angle = vector_angle(select(mask,corner-1,corner+1));
   anchor_dir = -zrot(angle/2,RIGHT);
   anchors = [named_anchor("corner", CTR,anchor_dir, _compute_spin(anchor_dir, UP))];
-  echo(anchors=anchors);
   default_tag("remove")
      attachable(anchor=anchor, spin=spin, orient=orient, h=length, scale=scale, path=mask, extent=atype=="hull", anchors=anchors){
        linear_sweep(mask,h=length,anchor="origin", scale=scale);

partitions.scad

@@ -201,6 +201,7 @@ function left_half(p,x=0) = half_of(p, LEFT, [x,0,0]);
 //   right_half(planar=true) circle(r=20);
 module right_half(s=100, x=0, planar=false)
 {
+    req_children($children);
     dir = RIGHT;
     difference() {
         children();

strings.scad

@@ -37,14 +37,16 @@ function _is_liststr(s) = is_list(s) || is_str(s);
 //   s5=substr("abcdefg",len=-2);  // Returns ""
 function substr(str, pos=0, len=undef) =
     assert(is_string(str))
-    is_list(pos) ? _substr(str, pos[0], pos[1]-pos[0]+1) :
-    len == undef ? _substr(str, pos, len(str)-pos) :
-    _substr(str,pos,len);
-
-function _substr(str,pos,len,substr="") =
-    len <= 0 || pos>=len(str) ? substr :
-    _substr(str, pos+1, len-1, str(substr, str[pos]));
+    is_list(pos) ? _substr(str, pos[0], pos[1]-pos[0]+1) 
+  : len == undef ? _substr(str, pos, len(str)-pos) 
+                 : _substr(str,pos,len);
 
+function _substr(str,pos,len) =
+    assert(pos>=0,"pos value for substr() must be nonnegative")
+    len <= 0 || pos>=len(str) ? ""
+  :
+    chr([for(i=[pos:pos+len-1]) ord(str[i])]);
+                              
 
 // Function: suffix()
 // Synopsis: Returns the last few characters of a string.
@@ -348,7 +350,7 @@ function str_pad(str,length,char=" ",left=false) =
   assert(is_str(char) && len(char)==1, "char must be a single character string")
   assert(is_bool(left))
   let(
-    padding = str_join(repeat(char,length-len(str)))
+    padding = chr(repeat(ord(char),length-len(str)))
   )
   left ? str(padding,str) : str(str,padding);
 
@@ -393,7 +395,7 @@ function str_replace_char(str,char,replace) =
 //   s=downcase("ABCdef");   // Returns "abcdef"
 function downcase(str) =
     assert(is_string(str))
-    str_join([for(char=str) let(code=ord(char)) code>=65 && code<=90 ? chr(code+32) : char]);
+    chr([for(char=str) let(code=ord(char)) code>=65 && code<=90 ? code+32 : code]);
 
 
 // Function: upcase()
@@ -411,7 +413,7 @@ function downcase(str) =
 //   s=upcase("ABCdef");   // Returns "ABCDEF"
 function upcase(str) =
     assert(is_string(str))
-    str_join([for(char=str) let(code=ord(char)) code>=97 && code<=122 ? chr(code-32) : char]);
+    chr([for(char=str) let(code=ord(char)) code>=97 && code<=122 ? code-32 : code]);
 
 
 // Section: Random strings
@@ -433,8 +435,8 @@ function upcase(str) =
 //    charset = string to draw the characters from.  Default: characters from "0" to "z".
 //    seed = random number seed
 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]]);
+  is_undef(charset)? chr(rand_int(48,122,n,seed))
+                   : chr([for(i=rand_int(0,len(charset)-1,n,seed)) ord(charset[i])]);
 
 
 
@@ -609,17 +611,16 @@ function parse_num(str) =
 // Example:
 //   str(123456789012345);  // Returns "1.23457e+14"
 //   format_int(123456789012345);  // Returns "123456789012345"
-//   format_int(-123456789012345);  // Returns "-123456789012345"
+//   format_int(-123456789012345); // Returns "-123456789012345"
+//   format_int(12,3);             // Returns 012
 function format_int(i,mindigits=1) =
     i<0? str("-", format_int(-i,mindigits)) :
     let(i=floor(i), e=floor(log(i)))
-    i==0? str_join([for (j=[0:1:mindigits-1]) "0"]) :
-    str_join(
-        concat(
-            [for (j=[0:1:mindigits-e-2]) "0"],
-            [for (j=[e:-1:0]) str(floor(i/pow(10,j)%10))]
-        )
-    );
+    i==0? chr([for (j=[0:1:mindigits-1]) 48]) :
+    chr([
+          for (j=[0:1:mindigits-e-2]) 48,
+          for (j=[e:-1:0]) 48+(floor(i/pow(10,j)%10))
+        ]);
 
 
 // Function: format_fixed()
@@ -715,7 +716,7 @@ function _format_matrix(M, sig=4, sep=1, eps=1e-9) =
        figure_dash = chr(8210),
        space_punc = chr(8200),
        space_figure = chr(8199),
-       sep = is_num(sep) && sep>=0 ? str_join(repeat(space_figure,sep))
+       sep = is_num(sep) && sep>=0 ? chr(repeat(ord(space_figure),sep))
            : is_string(sep) ? sep
            : assert(false,"Invalid separator: must be a string or positive integer giving number of spaces"),
        strarr=
@@ -832,7 +833,7 @@ function format(fmt, vals) =
                     typ=="G"? upcase(format_float(val,default(prec,6))) :
                     assert(false,str("Unknown format type: ",typ)),
                 padlen = max(0,wid-len(unpad)),
-                padfill = str_join([for (i=[0:1:padlen-1]) zero? "0" : " "]),
+                padfill = chr([for (i=[0:1:padlen-1]) zero? 48 : 32]),
                 out = left? str(unpad, padfill) : str(padfill, unpad)
             )
             out, raw