21 — Progress — showing how far along you are

A long job should show how far along it is. With nothing on screen it looks like the program has stopped. One bar is enough — a bar that gets one block longer with every step.

#Steps

1. A bar is one block repeated. It is the same sentence as in guide 20:

   set block to *
   show block repeated 3 times
   

   copyrun it →

   You get ***.

2. To choose the length you need to know which step you are on. Adding with place to a list loop tells you:

   set jobs to list of reading, adding up, saving
   for each job in jobs with place
       show place
       show job
   end
   

   copyrun it →

   You get 1 and reading, then 2 and adding up, then 3 and saving. Places are counted from 1.

3. Use that place as the length. One block on the first step, three on the third:

   set block to *
   set jobs to list of reading, adding up, saving
   for each job in jobs with place
       set bar to block repeated place times
       show bar
   end
   

   copyrun it →

   Each bar is one longer than the last, but they pile up.

4. Clear the screen before each one so they do not pile up. That is clear the screen from guide 14, and now the bar looks like it is growing:

   set block to *
   set jobs to list of reading, adding up, saving
   for each job in jobs with place
       set bar to block repeated place times
       clear the screen
       show job
       show bar
       wait 0.2 seconds
   end
   

   copyrun it →

   Without wait 0.2 seconds it is over before you can see it. A real program does the real work there instead of waiting.

5. The whole thing:

   set block to *
   set jobs to list of reading, adding up, drawing, saving
   for each job in jobs with place
       set bar to block repeated place times
       clear the screen
       show job
       show bar
       wait 0.2 seconds
   end
   show all done
   

   copyrun it →

#Try it yourself

Change set block to * to set block to # or set block to =. Then add more jobs to the list — the bar gets longer to match, and there is no length to fix anywhere.

#What you learned

• <block> repeated <n> times makes one row of a bar.
• with place on a list loop tells you which step you are on, counting from 1.
• Using that place as the length makes the bar grow one block per step.
• clear the screen before each draw keeps it growing in place instead of piling up.