GNU Info

(emacs-lisp-intro.info)Test print-graph

---

Next: Graphing words in defuns Prev: The final version Up: Print Whole Graph

---

Enter node , (file) or (file)node

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.)