                    |INTRODUCTION|


TCalc is a tiny spread sheet program.  It is provided as an example program
to help you learn the T programming language.  It may have some bugs in it.

The spread sheet is an electronic piece of paper on which you can 
enter text and arithmetic expressions with calculations done 
automatically or manually on command.

|Since it is only a demonstation program, it does have some limitations:
You cannot:|

  - copy from cells to other cells,

  - insert or delete lines or columns,

  - change cell widths.


|In spite of its limitations TCalc does provide some useful features.
You can:|

  - use built in mathematical functions ( abs, cos, ln, exp ... ),

  - save spread sheets to disk,

  - load spread sheets from disk,

  - print spread sheets,

  - clear spread sheets,

  - automatically or manually recalculate cell values,

  - change the numerical precision of cell values.




|This is what the spread sheet looks like:|

       A          B         C         D      . . . .
 1   14.00
 2    7.00
 3    4.00
 4    3.00
 5   28.00
 .
 .

|Expr:|
= A1 + A2 + A3 + A4

In the example the active cell is  |A5|  which contains the 
expression: = A1 + A2 + A3 + A4  shown in the text entry window.

The resulting value of the expression is shown on the spread sheet.


|Entering data|

A cell may contain an arithmetic expression or text. The type of the cell
is shown in the bottom left corner of the screen above the text entry line:

|Empty:|  - current cell is empty, neither text nor expression

|Text: |  - current cell contains text

|Expr: |  - current cell contains an arithmetic expression

To enter data in any field select the active cell using the arrow keys,
press |Tab|, and enter data at the cursor location.  

If you enter "=" at the extreme left, the line is assumed to be 
an arithmetic expression; otherwise it is assumed to be text.




|The following are examples of valid expressions:|

= 2
= 3.14159
= A1 / ( B2 - C7 )   
= sin( A1 ) * cos( A2 )
= 1.2 * ln( A1 + B1 ) + C1

|operators:|

+   add  
-   subtract
*   multiply
/   divide

|standard functions:|

abs, atan, cos, exp, ln, log, sin, sqr, sqrt


|Editing data|

To edit an existing formula or text simply move to the cell and
press |Tab|, make your changes and press |Enter|.  If you make
a mistake you can press |Esc|; the contents of the cell will
not be changed.

|When editing a field|

    |left arrow|   moves cursor to the left.
    |right arrow|  moves cursor to the right.
    |Back Space|   deletes the charater to the left of the cursor.
    |Delete|       deletes the character at the cursor.
    |Esc|          exits without changes to the cell.
    |Enter|        exits and processes changes to the cell.





|Commands:|

    |Q|uit TCalc

    |S|ave a spread sheet on the disk.

    |L|oad a spread sheet from the disk.

    |C|lear the current spread sheet.

    |R|ecalculate the values of the spread sheet.

    |P|rint the spread sheet.

    |F|ormat the numerical precision of values.

    |A|utomatic/manual recalculation mode switch.

