! branch.h

!---------------------------------------------------------------------------------
!
! branch.h
!
! a class for branching menus
!
! by Chris Klimas
!
! designed for Inform 6.15
! you can use this extension for free, but give me credit
!
!
! an overview:
!
! this a class definition.
!
! num_branches how many branches are in the set
!
! branch_1, etc the text of each branch
!
! chosen_1, etc a string of function, printed or run if
! the respective branch is chosen
!
! display call this function to display the branch
!
!
! how you should really use this library:
!
! step 1. draw all the branches out on paper. figure out what's going on,
! because once you start coding, everything gets more confusing.
! step 2. design an object for each branch point.
! step 3. code chosen_1, etc., appropriately to link to other branch_sets
! (by calling the next branch_set's display).
! step 4. test.
! step 5. repeat step 4.
!
! include this library before any branch_set definitions.
!
!---------------------------------------------------------------------------------

! This function is a low-level input hook.

[ Inkey key;
@read_char 1 key;
return key;
];

class branch_set
with
num_branches
1,
branch_1
[;
print "** Error: branch_1 undefined for ",(name) self;
],
branch_2
[;
print "** Error: branch_2 undefined for ",(name) self;
],
branch_3
[;
print "** Error: branch_3 undefined for ",(name) self;
],
branch_4
[;
print "** Error: branch_4 undefined for ",(name) self;
],
chosen_1
[;
print "** Error: chosen_1 undefined for ",(name) self;
InKey();
quit;
],
chosen_2
[;
print "** Error: chosen_2 undefined for ",(name) self;
InKey();
quit;
],
chosen_3
[;
print "** Error: chosen_3 undefined for ",(name) self;
InKey();
quit;
],
chosen_4
[;
print "** Error: chosen_4 undefined for ",(name) self;
InKey();
quit;
],
display
[ currentChoice choiceMade x;

! First, erase the upper window and print the menu items.

@erase_window 1; ! Erase the top window.
x = self.num_branches + 1;
@split_window x; ! Set it to the needed size.
@set_window 1;
style reverse; ! Clear the window to reverse
font off;
@set_cursor 1 1;
spaces((0->33)-1);
@set_cursor 2 1;
spaces((0->33)-1);
@set_cursor 1 2; ! Print each item.
print (string) self.branch_1;
if (self.num_branches > 1) {
@set_cursor 3 1;
spaces((0->33)-1);
@set_cursor 2 2;
print (string) self.branch_2;
};
if (self.num_branches > 2) {
@set_cursor 4 1;
spaces((0->33)-1);
@set_cursor 3 2;
print (string) self.branch_3;
};
if (self.num_branches > 3) {
@set_cursor 5 1;
spaces((0->33)-1);
@set_cursor 4 2;
print (string) self.branch_4;
};

! Now, go into a simple event loop that first prints an indicator of
! the currently selected item, then waits for a keypress, then
! adjusts currentChoice or sets choiceMade to true.

currentChoice = 1;
do {
font off; ! Clear the window to reverse
style reverse;
for(x=1:x==5:x++) {
@set_cursor x 1;
spaces((0->33)-1);
};
@set_cursor 1 2;
if (currentChoice == 1) style roman;
print (string) self.branch_1;
if (self.num_branches > 1) {
@set_cursor 2 2;
style reverse;
if (currentChoice == 2) style roman;
print (string) self.branch_2;
};
if (self.num_branches > 2) {
@set_cursor 3 2;
style reverse;
if (currentChoice == 3) style roman;
print (string) self.branch_3;
};
if (self.num_branches > 3) {
@set_cursor 4 2;
style reverse;
if (currentChoice == 4) style roman;
print (string) self.branch_4;
};

! Wait for a keypress and act on it.

switch(InKey()) {

! N,n,down arrow

78,110,130:
if (currentChoice < self.num_branches)
currentChoice++;
else
@sound_effect 2;

! P,p,up arrow

80,112,129:
if (currentChoice > 1)
currentChoice--;
else
@sound_effect 2;

! Return,right arrow

13,29:
choiceMade = true;

! Q,q

81,113: @sound_effect 2;

};
}
until (choiceMade);
@erase_window 1;
@set_window 0;
style roman;
font on;
switch(currentChoice) {

1:
self.chosen_1();

2:
self.chosen_2();

3:
self.chosen_3();

4:
self.chosen_4();

};
];