extract a module

I want to use `drawing` for locals, so I'll use uppercase the module
name just like globals.

drawing.lua

@@ -0,0 +1,51 @@
+-- primitives for editing drawings
+Drawing = {}
+
+function Drawing.draw(line, y)
+  local pmx,pmy = love.mouse.getX(), love.mouse.getY()
+  if pmx < 16+Drawing_width and pmy > line.y and pmy < line.y+pixels(line.h) then
+    love.graphics.setColor(0.75,0.75,0.75)
+    love.graphics.rectangle('line', 16,line.y, Drawing_width,pixels(line.h))
+    if icon[Current_mode] then
+      icon[Current_mode](16+Drawing_width-20, line.y+4)
+    else
+      icon[Previous_mode](16+Drawing_width-20, line.y+4)
+    end
+
+    if love.mouse.isDown('1') and love.keyboard.isDown('h') then
+      draw_help_with_mouse_pressed(line)
+      return
+    end
+  end
+
+  if line.show_help then
+    draw_help_without_mouse_pressed(line)
+    return
+  end
+
+  local mx,my = coord(love.mouse.getX()-16), coord(love.mouse.getY()-line.y)
+
+  for _,shape in ipairs(line.shapes) do
+    assert(shape)
+    if on_shape(mx,my, line, shape) then
+      love.graphics.setColor(1,0,0)
+    else
+      love.graphics.setColor(0,0,0)
+    end
+    draw_shape(16,line.y, line, shape)
+  end
+  for _,p in ipairs(line.points) do
+    if p.deleted == nil then
+      if near(p, mx,my) then
+        love.graphics.setColor(1,0,0)
+        love.graphics.circle('line', pixels(p.x)+16,pixels(p.y)+line.y, 4)
+      else
+        love.graphics.setColor(0,0,0)
+        love.graphics.circle('fill', pixels(p.x)+16,pixels(p.y)+line.y, 2)
+      end
+    end
+  end
+  draw_pending_shape(16,line.y, line)
+end
+
+return Drawing

main.lua

@@ -1,6 +1,7 @@
+local utf8 = require 'utf8'
 require 'keychord'
 require 'button'
-local utf8 = require 'utf8'
+local Drawing = require 'drawing'
 
 -- a line is either text or a drawing
 -- a text is a table with:
@@ -116,53 +117,8 @@ function love.draw()
           love.graphics.print('_', 25, y+6)  -- drop the cursor down a bit to account for the increased font size
         end
     elseif line.mode == 'drawing' then
-      -- line drawing
       y = y+pixels(line.h)
-
-      local pmx,pmy = love.mouse.getX(), love.mouse.getY()
-      if pmx < 16+Drawing_width and pmy > line.y and pmy < line.y+pixels(line.h) then
-        love.graphics.setColor(0.75,0.75,0.75)
-        love.graphics.rectangle('line', 16,line.y, Drawing_width,pixels(line.h))
-        if icon[Current_mode] then
-          icon[Current_mode](16+Drawing_width-20, line.y+4)
-        else
-          icon[Previous_mode](16+Drawing_width-20, line.y+4)
-        end
-
-        if love.mouse.isDown('1') and love.keyboard.isDown('h') then
-          draw_help_with_mouse_pressed(line)
-          return
-        end
-      end
-
-      if line.show_help then
-        draw_help_without_mouse_pressed(line)
-        return
-      end
-
-      local mx,my = coord(love.mouse.getX()-16), coord(love.mouse.getY()-line.y)
-
-      for _,shape in ipairs(line.shapes) do
-        assert(shape)
-        if on_shape(mx,my, line, shape) then
-          love.graphics.setColor(1,0,0)
-        else
-          love.graphics.setColor(0,0,0)
-        end
-        draw_shape(16,line.y, line, shape)
-      end
-      for _,p in ipairs(line.points) do
-        if p.deleted == nil then
-          if near(p, mx,my) then
-            love.graphics.setColor(1,0,0)
-            love.graphics.circle('line', pixels(p.x)+16,pixels(p.y)+line.y, 4)
-          else
-            love.graphics.setColor(0,0,0)
-            love.graphics.circle('fill', pixels(p.x)+16,pixels(p.y)+line.y, 2)
-          end
-        end
-      end
-      draw_pending_shape(16,line.y, line)
+      Drawing.draw(line, y)
     else
       love.graphics.setColor(0,0,0)
       local text = love.graphics.newText(love.graphics.getFont(), line.data)