use [each lt, v] to replace concat(lt, [v])

docs/lib3x-footprints2.md

@@ -20,32 +20,29 @@ Drive a turtle with `["forward", length]` or `["turn", angle]`. This function is
 			ta = fa / 2,
 			leng = sin(ta) * radius * 2
 		)
-		concat(
-			[["turn", ta]],
-			[
+        [
+            ["turn", ta],
+            each [
 				for(i = [0:steps - 2])
 				each [["forward", leng], ["turn", fa]]
 			],
-			[["forward", leng], ["turn", ta]]
-		);
+            ["forward", leng], 
+            ["turn", ta]
+        ];
 		
 	poly = footprints2(
-		concat(
-			[
-				["forward", 10],
-				["turn", 90],
-				["forward", 10] 
-			], 
-			arc_cmds(5, 180, 12),
-			[
-				["turn", -90],
-				["forward", 10],
-				["turn", 90],
-				["forward", 10],
-				["turn", 90],
-				["forward", 10]
-			]
-		)
+        [
+            ["forward", 10],
+		    ["turn", 90],
+			["forward", 10],
+            each arc_cmds(5, 180, 12),
+            ["turn", -90],
+            ["forward", 10],
+            ["turn", 90],
+            ["forward", 10],
+            ["turn", 90],
+            ["forward", 10]
+        ]
 	);
 
 	polyline_join(poly)

docs/lib3x-footprints3.md

@@ -20,33 +20,28 @@ A 3D verion of [footprint2](https://openhome.cc/eGossip/OpenSCAD/lib3x-footprint
 			ta = fa / 2,
 			leng = sin(ta) * radius * 2
 		)
-		concat(
-			[["turn", ta]],
-			[
+        [
+            ["turn", ta],
+            each [
 				for(i = [0:steps - 2])
 				each [["forward", leng], ["turn", fa]]
 			],
-			[["forward", leng], ["turn", ta]]
-		);
+            ["forward", leng], 
+            ["turn", ta]
+        ];
 
 	poly = footprints3(
-		concat(
-			[
-				["forward", 10],
-				["turn", 90],
-				["forward", 10] 
-			], 
-			xy_arc_cmds(5, 180, 12),
-			[
-				["pitch", 90],
-				["forward", 10],
-				["roll", 90]
-			],
-			xy_arc_cmds(5, 180, 12),
-			[
-				["forward", 10]
-			]
-		)
+        [
+            ["forward", 10],
+            ["turn", 90],
+            ["forward", 10],
+            each xy_arc_cmds(5, 180, 12),
+            ["pitch", 90],
+            ["forward", 10],
+            ["roll", 90],
+            each xy_arc_cmds(5, 180, 12),
+            ["forward", 10]
+        ]
 	);
 
 	polyline_join(poly)

docs/lib3x-hashmap.md

@@ -54,7 +54,7 @@ Want to simulate class-based OO in OpenSCAD? Here's my experiment.
     function clz_list(data) = function(name) _(name,
         methods([
             ["get", function(i) data[i]],
-            ["append", function(n) clz_list(concat(data, [n]))]
+            ["append", function(n) clz_list([each data, n])]
         ])
     );
 

docs/lib3x-path_extrude.md

@@ -257,7 +257,7 @@ So, which is the correct method? Both methods are correct when you provide only
 	// not closed perfectly
 	translate([-8, 0, 0]) path_extrude(
 		shape_pentagram_pts, 
-		concat(pts, [pts[0]]), 
+        [each pts, pts[0]], 
 		closed = true,
 		method = "AXIS_ANGLE"
 	);
@@ -265,7 +265,7 @@ So, which is the correct method? Both methods are correct when you provide only
 	// adjust it 
 	path_extrude(
 		shape_pentagram_pts, 
-		concat(pts, [pts[0]]), 
+		[each pts, pts[0]], 
 		closed = true,
 		twist = 188,
 		method = "AXIS_ANGLE"
@@ -274,7 +274,7 @@ So, which is the correct method? Both methods are correct when you provide only
 	// "EULER_ANGLE" is easy in this situation
 	translate([0, 8, 0]) path_extrude(
 		shape_pentagram_pts, 
-		concat(pts, [pts[0]]), 
+		[each pts, pts[0]], 
 		closed = true,
 		method = "EULER_ANGLE"
 	);

docs/lib3x-torus_knot.md

@@ -29,7 +29,7 @@ Generate a path of [The (p,q)-torus knot](https://en.wikipedia.org/wiki/Torus_kn
 
 	path_extrude(
 		shape_pentagram_pts, 
-		concat(pts, [pts[0]]), 
+        [each pts, pts[0]], 
 		closed = true,
 		method = "EULER_ANGLE"
 	);

docs/lib3x-tri_delaunay.md

@@ -32,7 +32,7 @@ Join a set of points to make a [Delaunay triangulation](https://en.wikipedia.org
 	color("red")
 	linear_extrude(3)
 	for(t = tri_delaunay(points, ret = "VORONOI_CELLS")) {
-	    polyline_join(concat(t, [t[0]]))
+	    polyline_join([each t, t[0]])
 		    circle(1);
 	}
 

docs/lib3x-tri_delaunay_indices.md

@@ -36,7 +36,7 @@ A method of [`tri_delaunay`](lib3x-tri_delaunay.html). Returns the indices from
 	color("red")
 	linear_extrude(3)
 	for(t = tri_delaunay_voronoi(delaunay)) {
-		polyline_join(concat(t, [t[0]]))
+		polyline_join([each t, t[0]])
 		    circle(1);
 	}
 

docs/lib3x-tri_delaunay_shapes.md

@@ -36,7 +36,7 @@ A method of [`tri_delaunay`](lib3x-tri_delaunay.html). Returns triangle shapes f
 	color("red")
 	linear_extrude(3)
 	for(t = tri_delaunay_voronoi(delaunay)) {
-		polyline_join(concat(t, [t[0]]))
+		polyline_join([each t, t[0]])
 		    circle(1);
 	}
 

docs/lib3x-tri_delaunay_voronoi.md

@@ -36,7 +36,7 @@ A method of [`tri_delaunay`](lib3x-tri_delaunay.html). Returns voronoi cells fro
 	color("red")
 	linear_extrude(3)
 	for(t = tri_delaunay_voronoi(delaunay)) {
-		polyline_join(concat(t, [t[0]]))
+		polyline_join([each t, t[0]])
 		    circle(1);
 	}
 

docs/lib3x-vrn2_cells_from.md

@@ -21,7 +21,7 @@ Create cell shapes of Voronoi from a list of points.
         cell = cells[i];
         
         linear_extrude(1)
-        polyline_join(concat(cell, [cell[0]]))
+        polyline_join([each cell, cell[0]])
 		    circle(.5);
         
         color(rands(0, 1, 3))

docs/lib3x-vrn2_cells_space.md

@@ -24,7 +24,7 @@ Create cell shapes of Voronoi in the first quadrant. You specify a space and a g
         cell_poly = cell[1];
 
         linear_extrude(1)
-		polyline_join(concat(cell_poly, [cell_poly[0]]))
+		polyline_join([each cell_poly, cell_poly[0]])
 			circle(.5);
         
         color(rands(0, 1, 3))

docs/lib3x-vx_polyline.md

@@ -18,7 +18,7 @@ Given a list of points. `vx_polyline` returns points that can be used to draw a
 			[round(pt.x), round(pt.y)]
 	];
 
-	for(pt = vx_polyline(concat(pentagram, [pentagram[0]]))) {
+	for(pt = vx_polyline([each pentagram, pentagram[0]])) {
 		translate(pt) 
 			linear_extrude(1, scale = 0.5) 
 			    square(1, center = true);