arr_curr()
During or immediately after the INPUT ARRAY or DISPLAY ARRAY statement arr_curr() returns the number of the program record within the program array that is displayed in the current line of a screen array, or the last active screen array if there is no current array.
The current line of a screen array is the line that displays the screen cursor at the beginning of a BEFORE ROW or AFTER ROW clause.
arr_curr() returns an integer value. The first row of the program array and the first line (that is, top-most) of the screen array are both numbered 1. The built-in functions arr_curr( ) and scr_line() can return different values if the program array is larger than the screen array.
You can pass arr_curr() as an argument when you call a function. In this way the function receives as its argument the current record of whatever array is referenced in the INPUT ARRAY or DISPLAY ARRAY statement.
arr_curr() can be used to force a FOR loop to begin beyond the first line of an array by setting a variable to arr_curr() and using that variable as the starting value for the FOR loop.
This program shows the differences between values returned by arr_curr( ) and scr_line().
The screen array defined in the form is 5 rows long. The program array defined in the 4gl is 20 rows long.
When a user moves to the 6th row by pressing "down arrow" key 5 times, the "Program array line" will be equal to 6 but the "Form array line" will remain equal to 5 because the screen array limit of 5 rows is reached.
Then, when a user moves up by pressing "up arrow" key, the "Program array line" will be equal to 5 and the "Form array line" will be equal to 4 because the user moved up one line on the screen array.
The ARR_CURR( ) function is frequently used with a DISPLAY ARRAY statement in popup windows to return the user’s selection.
arr_curr_function.4gl
MAIN
DEFINE arr1 ARRAY[20] OF RECORD
f1 CHAR(10),
f2 CHAR(10),
f3 CHAR(10)
END RECORD
DEFINE i, j INTEGER
OPEN WINDOW w_test
AT 2, 2
WITH FORM "arr_curr_function"
FOR i = 1 TO 20
LET arr1[i].f1 = "Row ", i USING "<&"
LET arr1[i].f2 = "Column 2"
LET arr1[i].f3 = "Column 3"
END FOR
CALL set_count(20)
DISPLAY ARRAY arr1 TO sc_rec.*
BEFORE ROW
LET i = arr_curr()
LET j = scr_line()
DISPLAY i TO f_arr_curr
DISPLAY j TO f_scr_line
END DISPLAY
CLOSE WINDOW w_test
END MAIN
arr_curr_function.per
DATABASE formonly
SCREEN
{
[f1 ] [f2 ] [f3 ]
[f1 ] [f2 ] [f3 ]
[f1 ] [f2 ] [f3 ]
[f1 ] [f2 ] [f3 ]
[f1 ] [f2 ] [f3 ]
Program\g \gArray\g \gLine [f16 ]
Form\g \gArray\g \gLine [f17 ]
}
ATTRIBUTES
f1=formonly.f1;
f2=formonly.f2;
f3=formonly.f3;
f16=formonly.f_arr_curr;
f17=formonly.f_scr_line;
INSTRUCTIONS
SCREEN RECORD sc_rec[5] (
formonly.f1,
formonly.f2,
formonly.f3
)
DELIMITERS "[]"