LI-COR LI-6400, Руководство пользователя, Страница: 614 / 846

Programming with LPL
Pointers
22-20 Using the LI-6400
22
When Go executes, three items are popped off the stack and assigned to
PTR s, allowing them to be later referenced
When the program in Figure 22-9 is run, it produces the following output:
Add: 1.23 + 5.67 = 6.9
Subtract: 1.23 - 5.67 = -4.44
Multiply: 1.23 * 5.67 = 6.9741
Divide: 1.23 / 5.67 = 0.216931
Undeclarable Foreign Objects
Another use of
PTR
s is for handling LPL objects that are not declarable. For
example, when a file is opened, a path to the file is created and put on the
stack. Since there is no declarable object in LPL to handle the path, we assign
:FCT Main
{
&Add "Add" "+" Go
&Sub "Subtract" "-" Go
&Mult "Multiply" "*" Go
&Div "Divide" "/" Go
GETKEY DROP
}
Go
{
:PTR symbol
:PTR label
:PTR action
1.23 :FLOAT x
5.67 :FLOAT y
label "%s: " PRINT
x y action :FLOAT result
result y symbol x "%g %s %g = %g\n" PRINT
}
Add {
+ }
Sub { - }
Mult { * }
Div { / }
Figure 22-9. PTRs and function parameter passing.