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C.4.1 Testing print-graph

We can test the print-graph function with a short list of numbers:

  1. Install the final versions of Y-axis-column, graph-body-print, and print-graph (in addition to the rest of the code.)
  2. Copy the following expression:
              (print-graph '(3 2 5 6 7 5 3 4 6 4 3 2 1))
    
  3. Switch to the *scratch* buffer and place the cursor where you want the axis labels to start.
  4. Type M-: (eval-expression).
  5. Yank the test expression into the minibuffer with C-y (yank).
  6. Press <RET> to evaluate the expression.

Emacs will print a graph that looks like this:

     10 -
     
     
              *
             **   *
      5 -   ****  *
            **** ***
          * *********
          ************
      1 - *************
     
          |   |    |    |
          1   5   10   15

On the other hand, if you pass print-graph a vertical-step value of 2, by evaluating this expression:

     (print-graph '(3 2 5 6 7 5 3 4 6 4 3 2 1) 2)

The graph looks like this:

     20 -
     
     
              *
             **   *
     10 -   ****  *
            **** ***
          * *********
          ************
      2 - *************
     
          |   |    |    |
          1   5   10   15

(A question: is the `2' on the bottom of the vertical axis a bug or a feature? If you think it is a bug, and should be a `1' instead, (or even a `0'), you can modify the sources.)