Editing 40d:Macro design

Playing Dwarf Fortress means lots of typing. Macros can reduce this typing, but they must be planned and designed carefully. This page discusses how to design a macro and avoid common problems. The specific operation or structure for which you are creating a macro is beyond the scope of this page.

== Macro delay ==
Forum and wiki participants have observed that some macros can take hours to run. This happens because there is a built-in delay between each macro command; since the game as shipped includes no preset macros, this delay is set to a value that allows the human player to see each move and debug any mistakes.

The solution is to change MACRO_MS in [[init.txt]] from 150 to 0. Most macros on any system commonly run better with some delay between commands{{verify}}; a MACRO_MS:1 seems to be a good run-time setting.

== Planning ==
There are thousands of ways to do anything, but we would like to pick the best or near-best solution. In the case of DF's macros we want to see our macro run in the fewest steps possible, getting the most out of each command. 

Start by planning out your design as a series of steps to create the final result. Then code each step individually, while taking note of the before and after steps. Like the complete macro, each step has many possible different coding solutions. Try to pick one that is simple (short) but also goes best with the step before it, and will end somewhere that's advantageous for the next step. Try to keep a step to a single type of operation; this will save the time of continuously switching between modes.

:Example: Fields (boxes or area-selections) have four corners. Your code traverses from one corner to the opposite corner to define the field. It doesn't matter which corner you start at. So pick a start and stop point of your field that's convenient for the next and previous steps. This saves a lot of time spent walking the cursor around.

== Repeats ==
The macro syntax allows commands to be repeated using a numeric parameter. The following scripts take the same time to execute.

 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]
 [MACRO:CURSOR_UP:1]

 [MACRO:CURSOR_UP:'''20''']

The condensed version is more readable, but these work the same way.

== Movement ==
Most of the time a macro takes to run is spent moving the cursor around. This can be sped up through the use of the "_FAST" versions of the move commands and by moving diagonally.

=== Fast movement ===
When you hold the {{key|Shift}} key in the game UI and press an arrow key, the cursor moves ten squares instead of one. Similarly, each cursor command has a "_FAST" version that jumps ten squares in the same time a normal movement command takes to travel on square.

The following code,

 [MACRO:CURSOR_UP:33]

is the same as 33 moving commands however,

 [MACRO:CURSOR_UP_FAST:3]
 [MACRO:CURSOR_UP:3]

is the exact same action in only 4 commands.

=== Backpedaling ===
When the 1's digit is higher than 5, backing the cursor up can achieve faster run times.

 [MACRO:CURSOR_UP:38]

Can be sped up with _FAST commands:

 [MACRO:CURSOR_UP_FAST:3]
 [MACRO:CURSOR_UP:8]

This brings 38 commands down to just 11. However this can be better optimized by moving ''past'' the intended destination and backing up.

 [MACRO:CURSOR_UP_FAST:4]
 [MACRO:CURSOR_Down:2]

Is the exact same cursor position change but in only 6 moves. This can have [[#Edge collision|side effects]] however and must be done carefully.

=== Diagonal movement ===
Most people using modern keyboards are familiar with the T-shaped arrow key block. The numeric keypad has arrows too, and on some keyboards the {{key|1}} {{key|3}} {{key|7}} {{key|9}} keys have arrows as well. Regardless of whether your numeric keypad has arrows on it, you can move with the {{key|1}} {{key|3}} {{key|7}} {{key|9}} keys. Diagonal movement is also possible in macros, and it can be used to reduce the number of commands required.

 [MACRO:CURSOR_UP:8]
 [MACRO:CURSOR_RIGHT:8]

can be replaced by

 [MACRO:CURSOR_UPRIGHT:8]

This dropped the command count from 16 to 8. It also works for non-squares too.

 [MACRO:CURSOR_UP:12]
 [MACRO:CURSOR_RIGHT:16]

can be replaced by

 [MACRO:CURSOR_UPRIGHT:12]
 [MACRO:CURSOR_RIGHT:4]

This saved us 12 unneeded commands.

The "_FAST" works in the game and in your scripts on diagonals too. Further bringing down the the previous example command count to just,

 [MACRO:CURSOR_UPRIGHT_FAST:1]
 [MACRO:CURSOR_UPRIGHT:2]
 [MACRO:CURSOR_RIGHT:4]

So from 38 commands to just 7, with a little planning.

Diagonal movement commands are written as '''vertical''' then '''horizontal''' with no separating "_"

=== Final cursor placement ===
When designing scripts, it's a good idea to plan where to leave off. The two common ideas are:
* Back where the script started, which is less disorienting to the user. This is best for macros that are intended to be used once.
* In position for an instant repeat of the macro, for macros that are likely to be used several times in a row.
If your macro makes a 3 square wide section of hallway to the left, then put the cursor in a position that allows for a repeat call of the macro to add a second section.

Both are better than just stopping the cursor wherever it happens to be.


= Troubleshooting =

== Off-by-one errors ==
When your script doesn't run as planned, check if you went too far on a movement action. This can happen if you confuse the number of squares ''designated'' with the number of squares ''moved''.

For example, to make a '''5x5''' box, use 4's instead of 5's:

 [MACRO:SELECT:1]
 [MACRO:CURSOR_LEFT:'''4''']   
 [MACRO:CURSOR_UP:'''4''']
 [MACRO:SELECT:1]

The cursor's current position always counts as 1 "extra" square, since you're defining movement, not a size.

 #     1 square ''designated'', '''0''' squares ''moved''
 
 ##    2 squares ''designated'', '''1''' square ''moved''
 
 ###   3 squares ''designated'', '''2''' squares ''moved''

== Edge collision ==
When the cursor hits an edge of the map, it stops there, no matter how far your script wants to travel that way. This is per command, and if you're not expecting to hit an edge, this will corrupt that execution of the script. To avoid this, the script-runner must ensure that the script has enough room to run when it is started. The script-designer can help by clearly documenting how much space is needed.

Scripts can also run into trouble with [[#Backpedaling|backpedaling optimizations]]. Backpedaling can extend your script's running area beyond the area where it is making changes. If the script-runner only leaves enough space for the changes themselves, there is a risk that any _FAST jumps outside that area will be shortened by hitting an edge, and any subsequent backpedaling operations will then start from the wrong position. Therefore, it is recommend to only use backpedaling that does not go outside of your script's work area.

For example, if your script operates inside a 17x4 rectangle, getting across it with the following code,

 [MACRO:CURSOR_RIGHT_FAST:2]
 [MACRO:CURSOR_LEFT:3]

will place the cursor incorrectly if an edge is 19 squares away.

For script areas of 6, 7, 8, or 9, it may be wise to avoid backpedaling entirely, since any _FAST operation would move the cursor outside that range. But with a script area that small, speed probably isn't as much of an issue.

For areas larger than 10 spaces, reordering the commands can keep the cursor in-range while still using backpedaling optimizations. The above example is equivalent to this:

 [MACRO:CURSOR_RIGHT_FAST:1]
 [MACRO:CURSOR_RIGHT_FAST:1]
 [MACRO:CURSOR_LEFT:3]

Which we can reorder to:

 [MACRO:CURSOR_RIGHT_FAST:1]
 [MACRO:CURSOR_LEFT:3]
 [MACRO:CURSOR_RIGHT_FAST:1]

This is the same run time and number of commands, yet the cursor says inside the script area. The backpedaling "LEFT:3" command now applies to the first "_FAST" command, rather than the second. (Note that if it had been placed ''first'', the cursor would have backpedaled out the other side.)

[[Category:Guides]]
[[Category:Interface]]