10. Housekeeping

In an extended session it may be difficult to remember the
names assigned to verbs and nouns; the foreign
conjunction !: (detailed in
Appendix A)
provides facilities for displaying and erasing them. For example:

   b=: 3* a=: i. 6
   sum=: +/
   tri=: sum a
   names=: 4!:1
   names 0
   names 3
   erase=: 4!:55
   erase <'tri'
   names 0 3
   erase names 0
1 1
   names 0 3

The Windows drop-down menus can be used to save, retrieve,
and print sessions. They can also be used to open script windows,
in which any number of sentences may be entered and edited,
and from which they can be executed so as to appear
in the normal execution window.

The script and execution windows can also be displayed
side-by-side, so that the effect of executing scripts
can be directly observed.

These matters are treated in detail in the help files,
as are the housekeeping facilities provided by the script
file profile.ijs. The menus may be used to execute
this file explicitly so as to make its facilities available.
If, however, its name is included in the command line
(as described in the user manual) it is executed automatically
at the beginning of a session.


10.1   Enter and experiment with the programs defined in this section.

10.2   Type in the sentence +/ 2 3 5 * i. 3 and press the
Enter key to execute it.

10.3   Use the Up-arrow cursor key to move the cursor back up
the line entered in Exercise 10.2, and then:

Press Enter to bring the line down to the input area.

Use the Left-arrow key to move the cursor back to the * symbol,
and the backspace key to erase it.

Enter - to replace the multiplication by subtraction,
and press the Enter key to execute the revised sentence.

10.4   Use cursor keys to move the cursor to the immediate
left of the i in the sentence executed in Exercise 10.3.
Then hold down the Control key and press the F1 key to display
Dictionary definition of the primitive i.

10.5   Press the Escape key to close the display invoked in
Exercise 10.4. Then move the cursor to the left so that it is
separated from the line by one or more spaces, and again
perform Ctrl F1 to display the individually boxed words in the sentence.