Intro 10. Housekeeping

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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
    +-+-+---+
    |a|b|tri|
    +-+-+---+

       names 3
    +-----+---+
    |names|sum|
    +-----+---+

       erase=: 4!:55
       erase <'tri'
    1

       names 0 3
    +-+-+-----+-----+---+
    |a|b|erase|names|sum|
    +-+-+-----+-----+---+

       erase names 0
    1 1

       names 0 3
    +-----+-----+---+
    |erase|names|sum|
    +-----+-----+---+

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.

Exercises

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.
The following exercises describe facilities available only under Windows and Macintosh.
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.

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