.\"	$NetBSD: form_driver.3,v 1.11 2010/03/22 21:58:31 joerg Exp $
.\"
.\" Copyright (c) 2001
.\"	Brett Lymn - blymn@baea.com.au, brett_lymn@yahoo.com.au
.\"
.\" This code is donated to The NetBSD Foundation by the author.
.\"
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.Dd January 1, 2001
.Dt FORMS 3
.Os
.Sh NAME
.Nm form_driver
.Nd form library
.Sh LIBRARY
.Lb libform
.Sh SYNOPSIS
.In form.h
.Ft int
.Fn form_driver "FORM *form" "int request"
.Sh DESCRIPTION
The
.Fn form_driver
is the heart of the forms library, it takes commands in the
.Fa request
parameter that is either a request to the driver to perform some
action or is a character to be inserted into the current field.
The form driver will attempt to insert any printable character passed to
it into the current field.
This may or may not succeed depending on the state of the current field.
If the character passed is not
printable then the driver attempts to process it as a driver request.
If the character passed is not a valid request then the driver will
return an unknown command error.
.Sh PARAMETERS
The forms driver recognizes the following requests:
.Pp
.Bl -tag -width REQ_SFIRST_FIELD -compact
.It REQ_NEXT_PAGE
Change to the next page in the form.
.It REQ_PREV_PAGE
Change to the previous page in the form.
.It REQ_FIRST_PAGE
Select the first page in the form.
.It REQ_LAST_PAGE
Go to the last page in the form.
.It REQ_NEXT_FIELD
Move to the next field in the form field array.
.It REQ_PREV_FIELD
Move to the previous field in the form field array.
.It REQ_FIRST_FIELD
Go to the first field in the form field array.
.It REQ_LAST_FIELD
Go to the last field in the form field array.
.It REQ_SNEXT_FIELD
Move to the next sorted field on the form.
.It REQ_SPREV_FIELD
Move to the previous sorted field on the form.
.It REQ_SFIRST_FIELD
Go to the first field in the sorted list.
.It REQ_SLAST_FIELD
Move to the last field in the sorted list.
.It REQ_LEFT_FIELD
Go one field to the left on the form page.
.It REQ_RIGHT_FIELD
Go one field to the right on the form page.
.It REQ_UP_FIELD
Go up one field on the form page.
.It REQ_DOWN_FIELD
Go down one field on the form page.
.It REQ_NEXT_CHAR
Move one char to the right within the field
.It REQ_PREV_CHAR
Move one char to the left within the current field.
.It REQ_NEXT_LINE
Go down one line in the current field.
.It REQ_PREV_LINE
Go up one line in the current field.
.It REQ_NEXT_WORD
Go forward one word in the current field
.It REQ_PREV_WORD
Go backward one word in the current field.
.It REQ_BEG_FIELD
Move the cursor to the beginning of the current field.
.It REQ_END_FIELD
Move the cursor to the end of the current field.
.It REQ_BEG_LINE
Move the cursor to the beginning of the line in the current field.
.It REQ_END_LINE
Move the cursor to the end of the line.
.It REQ_LEFT_CHAR
Move the cursor left one character
.It REQ_RIGHT_CHAR
Move the cursor right one character
.It REQ_UP_CHAR
Move the cursor up one line.
.It REQ_DOWN_CHAR
Move the cursor down one line.
.It REQ_NEW_LINE
Insert a new line at the current cursor position.
.It REQ_INS_CHAR
Insert a blank character at the current cursor position
.It REQ_INS_LINE
Open a blank line at the current cursor position.
.It REQ_DEL_CHAR
Delete the character at the current cursor position.
.It REQ_DEL_PREV
Delete the character to the left of the current cursor position.
.It REQ_DEL_LINE
Delete the current line.
.It REQ_DEL_WORD
Delete the word at the current cursor position.
.It REQ_CLR_EOL
Clear the field from the current cursor position to the end of the
current line.
.It REQ_CLR_EOF
Clear the field from the current cursor position to the end of the field.
.It REQ_CLR_FIELD
Clear the field.
.It REQ_OVL_MODE
Enter overlay mode, characters added to the field will replace the
ones already there.
.It REQ_INS_MODE
Enter insert mode, characters will be inserted at the current cursor
position.
Any characters to the right of the cursor will be moved
right to accommodate the new characters.
.It REQ_SCR_FLINE
Scroll the field forward one line.
.It REQ_SCR_BLINE
Scroll the field backward one line.
.It REQ_SCR_FPAGE
Scroll the field forward one field page.
.It REQ_SCR_BPAGE
Scroll the field backward one field page.
.It REQ_SCR_FHPAGE
Scroll the field forward half one field page.
.It REQ_SCR_BHPAGE
Scroll the field backward half one field page.
.It REQ_SCR_FCHAR
Scroll the field horizontally forward one character
.It REQ_SCR_BCHAR
Scroll the field horizontally backward one character
.It REQ_SCR_HFLINE
Scroll the field horizontally forward one field line.
.It REQ_SCR_HBLINE
Scroll the field horizontally backward one field line.
.It REQ_SCR_HFHALF
Scroll the field horizontally forward half a field line.
.It REQ_SCR_HBHALF
Scroll the field horizontally backward half a field line.
.It REQ_VALIDATION
Request the contents of the current field be validated using any field
validation function that has been set for the field.
Normally, the field is validated before the current field changes.
This request allows the current field to be validated.
.It REQ_PREV_CHOICE
Select the previous choice in an enumerated type field.
.It REQ_NEXT_CHOICE
Select the next choice in an enumerated type field.
.El
.Sh RETURN VALUES
Functions returning pointers will return
.Dv NULL
if an error is detected.
The functions that return an int will return one of the following error
values:
.Pp
.Bl -tag -width E_UNKNOWN_COMMAND -compact
.It Er E_OK
The function was successful.
.It Er E_REQUEST_DENIED
The forms driver request could not be fulfilled
.It Er E_UNKNOWN_COMMAND
The passed character is not a printable character and is not a valid
forms driver request.
.It Er E_BAD_ARGUMENT
A bad argument was passed to the forms driver.
.It Er E_INVALID_FIELD
The form passed to the driver has no valid attached fields.
.It Er E_NOT_POSTED
The given form is not currently posted to the screen.
.It Er E_BAD_STATE
The forms driver was called from within an init or term function.
.It Er E_INVALID_FIELD
The character passed to the forms driver fails the character
validation for the current field.
.El
.Sh SEE ALSO
.Xr curses 3 ,
.Xr forms 3
.Sh NOTES
Field sorting is done by location of the field on the form page, the
fields are sorted by position starting with the top-most, left-most
field and progressing left to right.
For the purposes of sorting, the
fields top left corner is used as the sort criteria.
The header
.In form.h
automatically includes both
.In curses.h
and
.In eti.h .