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The forms procedures give an example of a display handling library
built on top of the curses routines. The forms procedures divide the
terminal screen into two windows, the form and prompt window. The
form window contains the form fields. Each field in the form occupies
one line on the screen with the field name on the left side of the
line and the field value on the right side separated by an equals
sign. If the number of fields in the form exceed the number of lines
in the form window, a portion of the fields will be displayed, which
the user can scroll through. The prompt window is used to read user
input and display messages. The first line contains a message,
typically used to list the possible commands, and the second line
contains the user input.
The following two procedures are used to initialize and terminate the
form handling. The first procedure, fm_begin, calls the keyboard and
screen initialization routines, and initializes some global variables.
The second procedure, fm_end, calls the keyboard and screen
termination routines.
procedure fm_begin ()
procedure fm_end ()
The next three procedures handle the form window of the screen. The
first procedure, fm_mkform(), associates a form with a window. The
second procedure, fm_getform(), gets user input from the form. The
third procedure, fm_endform(), frees the data structure associated
with the form.
The first procedure has the following calling sequence:
procedure fm_mkform (win, nfield, lenname, lenvalue, title, ftype, fname)
int win # i: Window descriptor
int nfield # i: Number of fields in form
int lenname # i: Declared length of field name
int lenvalue # i: Declared length of field value
char title[ARB] # i: Form title
int ftype[ARB] # i: Data types of fields
char fname[lenname,ARB] # i: Names of fields
The first argument, win, is the window descriptor. It is created by
calling newwin(), the curses procedure which creates windows. The next
three arguments are used to compute the size of the structure which
holds the form. The number of fields can be greater than the height of
the window, as the window will scroll up and down. But the combined
length of the field name and value must be less than the width of the
window, as it will not scroll side to side. The title is a string that
is printed on the title bar, which is the bottom row of the form. The
title bar also contains the help key escape sequence. Three items of
information are associated with each field: a type, a name, and a
value. The type is an integer with the same meaning used by the table
interface: a negative number if the field is a string whose magnitude
is equal to the maximum string length or a positive integer equal to
the spp type code if the field is not a string. The type is used to
check the field value, the procedure will not let the user enter a
value of a different type. Each field name is printed on a separate
line of the form followed by an equals sign.
The second procedure, fm_getform, is used to read or display the
values associated with the fields of the form. It has the following
calling sequence:
procedure fm_getform (win, redraw, lenvalue, fvalue)
int win # i: Window descriptor
bool redraw # i: Redraw screen?
int lenvalue # i: Declared length of field value
char fvalue[lenvalue,ARB] # u: Values in fields
The first argument is the window descriptor of the window associated
with the form. If the second argument, redraw is set to true, the
window is redrawn when the procedure begins, otherwise the window is
unchanged. Redraw should set to true the first time this procedure is
called. The last argument, fvalue, contains the values that are
displayed on the form. The user updates these values by editing the
form on the screen. When the user has finished updating the values,
the modified values are returned to the calling procedure.
The third procedure frees the form data structure. After freeing the
data structure, the window should be closed by calling delwin. This
procedure has the following calling sequence:
procedure fm_clsform (win)
int win # i: Window descriptor
The next procedure, fm_prompt, handles the prompt window on the screen.
It has the following calling sequence:
int procedure fm_prompt (commands, message)
char commands[ARB] # i: List of commands
char message[ARB] # i: Message to print in prompt area
The list of commands is a string containing the possible commands. This
string is formatted like the dictionary in strdic: the first character
in the string is a command separator which appears between the commands
in the string. The message is displayed on the top line of the prompt
area. If the message is a null string, the command string is displayed
instead. The user enters one of the commands and presses carriage
return. The procedure returns the number of the command that the user
entered if the command is legal, or beeps and displays the list of
commands if it is not. If the list of commands is a null string, the
procedure displays the message in the prompt area and returns a value
of zero without looking for user input.
The last procedure displays the help window. This window covers the
entire screen. Its argument is the currently active window. It is
passed so that the cursor can be restored to its previous position
when the procedure is finished.
procedure fm_help (win)
int win # i: Window which currently is active
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