Moe's Mushkode Manual - Building on the mywho command.

Author: Moe
Category: Globals
Commands: @emit, @pemit.
Compatibility: TinyMUSH.

MUSHCode for Moe's Mushkode Manual - Building on the mywho command.

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| \/ |oe's | \/ |ushkode | \/ |anual


Alright, in our last lesson, we handled a number of basics of
mushcoding, and created a 'mywho' command that did a couple of basic
coding procedures. It looked something like:

&cmd_mywho obj=$mywho:@pemit

Look familiar? Make sense? If the answer to both is no, go back
and read Lesson 1 of this tutorial. If the answer to only the second
question is no, go back and read Lesson 1 of this tutorial. If it at least
makes sense, let's move on.


At this point in the tutorial, we're going to start making our
code look a bit cleaner, and also by learning these methods, we'll start
finding ways to make the tracking down of bugs easier. It is possible,
through the use of something called u-functions, to break your code up
into chunks, creating in essence subroutines.
This is useful if your code is going to be using the same bits
time and time again, and you don't want to have to type them out each
time. Or, if your command is starting to get lengthy and full of various
parentheses that you're afraid you'll lose track of, it's time to use
In short, a u-function is a user-defined function routine that can
be stored in an attribute separate from the one in which the command is
stored. Since they are going to be stored in an attribute(all mushcode is
stored in attributes, so this should come as no surprise), it is helpful
to adopt a naming convention, as discussed in Lesson 1.
There are many possibilities for what you can name your u-function
attributes. fn_dostuff would be the name of an attribute that did stuff,
and by its name, you would know it was a function routine. do_stuff is
also valid. Whatever works for you, great. Stick with it, and be
consistent. In the offchance that someone has to maintain your code, it is
helpful if you name your attributes logically and clearly.
If you look at our mywho from above, you'll notice that where the
switch() is, it's starting to get a little cumbersome with the
parentheses. So, let's put this into a u-function. Let's name it fn-sex,
as this tells us that it is a function that handles or checks sex in some
way. (Naughty minds, I tell you!)
Now, our ufun(short for u-function) is going to need to be able to
accept the dbref that is being iterated in each pass of our command. This
is where we learn about passing parameters.


As if on cue, eh? Parameters are values passed from one piece of
code to another. There are certain hard and fast rules for doing this, so
you don't have to worry too much about being confused. First, you can only
pass up to ten parameters. They are always accepted in the order in which
they are passed, and their order will always be referenced the same
way. Mushes store parameters in %0-%9. %0 is always the first parameter
passed, %1 the second, %2 the third, etc.
Now, our switch() routine from above only has one element of it
that changes, the ##. We will turn that into %0, since that is the first
parameter that can be passed. In our case, it will be the only one. Here
is how our ufun will look.


Why are there brackets around it, you ask? If you remember your
rules, you know that brackets force the evaluation of functions. This
entire routine is functions, and we want to be sure that it evaluates,
regardless of what may come before it where it was called. It is better to
always enclose your ufuns in brackets than to risk having it not be
Now, how do we call this wonder of coding technology, you
ask? Even if you didn't, here's how. We rewrite our cmd_mywho to include a
u() function. This is how ufuns got their name, because they are invoked
by the u() function.


There is a lot of confusion with beginning coders about the
difference between v() and u(). Let me pause in our mywho development to
explain this, in a modest amount of detail. As I just explained, u() is
used to invoke a subroutine of functions. It follows the syntax:
u([<obj>/]<attribute>,[<param>])This means it is telling the mush:
'Evaluate the contents of this attribute.'
If you specify an object and an attribute, it means you want to
read and evaluate an attribute stored on an object other than that which
the code you're using is on. Parameters are optional, as not all ufuns
require them. But, they can be included, if necessary.
v() on the other hand, does none of these things. The v() function
only returns the value of an attribute(V, value, get it?). It does not do
any substitution, evaluation, nor can v() fetch an attribute from another
object. It can only see attributes on the same object as the code, and
will only ever return what is stored in that attribute. It will not do
/any/ evaluation.
Here's how I learned to remember it. v() gives me the value of an
attribute. u() uses the attribute. V - value. U - use. Simple, no? I hope
so. Back to our regularly scheduled tutorial.


Where our switch() was before in our mywho, we are going to put
the following code:


What this does is tells the command to 'use' the functions stored
in the attribute named fn-sex, stored on the same object that the command
is on. It tells it also to use the current value of ##, which will be
passed as %0. So, now our new mywho looks like:

&cmd_mywho obj=$mywho:@pemit %#=iter(lwho(),u(fn-sex,##),,%R)

Looks a lot better than it did when we started, doesn't
it? Cleaner, and more maintainable. Because now, we can change fn-sex if
we want to change something about the display, and we don't have to change
our mywho command at all. Such is one of the benefits of ufuns. They are
your friend.
We can take it even a step further. We could have a fn-mywho that
does our iter(), and calls fn-sex from within it. And then our mywho
command would simply be:

&cmd_mywho obj=$mywho:@pemit %#=u(fn-mywho)

We could do that, yes. But, I like to see something in my
command. Makes me feel like I did something. As well, there are some small
efficiency reasons not to do this. If an object is set to be read for
$commands, then the mush is going to check every attribute on that object
for $commands, each time a command is entered. It can get tedious to set
each and every function attribute to no_command, if you want to be the
most efficient about it.
What? Setting function attributes to no_command?? Yes, you can do
that. They aren't commands in and of themselves, and setting them
no_command doesn't stop their evaluation. It just tells the mush not to
look at them when trying to match a $command used by a player. And now,
for something completely different.


Quite often as coders, we are faced with the task of making
something we produce look nice on the screen. This involves a lot of
justifying, centering, truncating...a mess of things that get in the way
of doing actual manipulation of data. But, if you learn a few simple
tricks, you can institute some good habits and ease the path of what I
like to call 'Cosmetic Coding'.
First tenet of cosmetic coding is this: Always code for a
78-column screen. Even in the beginning of the 21st century, where it's
feasible to have a 1600x1400 resolution screen, your standard terminal
window is designed to be 80 columns wide. By limiting yourself to
78-column coding, you are going to always have a presentation that can be
viewed by anyone logging on to your mush. Only coding for people who see
things in 140 columns is not going to win you any friends that are Linux
users, for instance.
A side note that I should throw in here while I am at it. Not
everyone uses a fixed-width font anymore. In the old days, it was fixedsys
and courier new. Now, there are more fonts than flavours of Nehi, and only
a select few of them are fixed-width font. All of the careful coding for
alignment in the world will go quickly out the window when viewed in a
variable-width font. To make sure that your code is going to be properly
justified, make sure you're looking at it in Courier New, or a similar
fixed-width font.
While I could spend a lot of time talking about how to do ascii
borders, and artistic things like that, I am going to focus more on the
justification and alignment of text, taking our mywho in a wholly new
direction in the process. We are going to revamp our fn-sex so that it
displays two columns of data. One is the character's name, and the other
is their sex.
Now, for starters, let's begin with the following code:

&fn-sex obj=[name(%0)] [xget(%0,sex)]

Type that in, and then run your mywho command. You'll see the data
you requested, and most likely you'll have one column of names that is
nicely left-justified and a column of gender specifications that is
uneven, as it's spaced based on what the character's name is.
A lot of beginning coders at this point will think to fix that by
putting a %t between the name() and the xget() functions, thinking that
will provide a uniform distance between the two. It doesn't, for two
One, not everyone has the same tab width set on their client.
While 3 or 4 spaces is the most common, it is by no means universal, and
those two values by themselves are different and therefore can cause
specific alignment problems.
Two, the %t only moves the text to the next tab stop on the
screen. That may be in one or seven spaces, depending on the length of the
text preceding it. Again, while it's a nice idea, you have no guarantee
that it's going to align your text properly. There is a better way.


Mushcode provides you with three justification functions. ljust(),
rjust(), and center(). All three of these functions behave similarly, in
that they allow you to specify a total column width that you would like to
put your text in, and providing that your text isn't longer than that
width, it will pad the appropriate end(s) of your text with whitespace in
order to achieve the total length.
These three functions also allow you to pad the supplied text with
a character other than a blank space, and thanks to this, we are able to
visually see how they work, in order to understand them better. Enter the
following command(think doesn't exist on TinyMUSH2.2, so I suggest using
@pemit me= or @emit instead):

think ljust(Word,10,+)%R[rjust(Word,10,+)]%R[center(Word,10,+)]

You should get back something that looks like this:


You can see how the mush pads the text you supply to make the
output be the assigned length. We can use this to our advantage when we
are doing cosmetic coding, because it allows us to make fixed-width
columns that will always line up. Consider the following modification to

&fn-sex obj=[ljust(name(%0),25)][xget(%0,sex)]

Type that in, and then run your mywho command again. Providing
that none of your characters have names greater than 25 characters, it
should look pretty snazzy. Now why didn't we justify the sex column? It
wasn't necessary. You only need to left-justify something in order to
align what comes /after/ it. There is nothing after the sex on each line,
so there is no need to justify that column.


Something that will help both you as a coder, and your users, is
avoiding blank space to signify that something doesn't exist. It is as
much a part of robust coding as it is cosmetic coding, and so I shall
address it here, while you're still relatively impressionable in your
coding skills and habits.
Consider our current fn-sex, and the case of two or three
characters that don't have their @sex attribute set. As it is now, the
xget() will simply retrieve a null string, or no value. This means that
they don't have their sex set, and we intellectually know that. But, in
the spirit of learning to code for other people, let's learn how to
provide some basic data for most any situation. We'll use the
default() function.
Default() looks for an attribute and tries to read its value, a la
v(). If it either a) can't find the attribute, b) can't read the attribute
due to permissions or lack thereof, or c) the attribute has no value, it
will return a 'default' value. Guess how the function got its name? Here
is the syntax for default(): default(obj/attr,default)
And here is how we are going to implement it in our fn-sex:

&fn-sex obj=[ljust(name(%0),25)][default(%0/sex,Not set.)]

This will produce two columns that are guaranteed to have data on
each line, in both columns. It will tell us the character's name, and
their sex, if it is set. If it is not, it will tell us 'Not set.'. If
someone comes behind us and uses our mywho command, they will have a much
clearer understanding of what the command is displaying, through the
simple use of this function.


One of the onerous jobs of the mushcoder is truncating text to fit
in a field. In our current case, we're going to expand our mywho command
and learn how to truncate at the same time. And we're going to expand our
usage of the default() function as well. Now you know why I just made you
learn it, don't you?
While it's not quite universal, it can be considered a standard
convention of most RP mushes to have players set a &fullname attribute on
their character to indicate what the full name of their beloved creation
is, as opposed to simply the screen name by which they login. For the next
level of our mywho, let's adjust our display so that it gives us the
fullname attribute, if set, and if not, just gives us the character's
name. We will need to justify this column, still, and also truncate so
that it doesn't run over our specified width.
Sadly, ljust(), rjust(), and center() do not truncate for us. If
the text is wider than the width we specify, it will simply display the
text as is. The solution for this is the simple inclusion of the
left() function. This function returns the leftmost number of characters
that we specify. left(This is a test,8) would return 'This is '
We learned from our previous bit that default() looks for the
value of one attribute, and either returns that, or a default value. So,
let us proceed to figure out first how to apply that to a fullname
attribute. We know the player's dbref is being passed as %0, so it becomes
as simple as: default(%0/fullname,name(%0))
This then needs to be truncated and justified. Two more functions,
coming right up. You want fries with that?


I chose to take the 24 leftmost characters and put them in a field
of 25 spaces, that way we are always assured of having at least one column
of whitespace between our name column and our sex column. Whitespace is
necessary for the brain to be able to distinguish between pieces of
information. Make sure to give your users some(both whitespace /and/
pieces of information, that is).
Now, we just need to redo our fn-sex, so that it looks like:


There. Got all that? Run your mywho again, and marvel in the
elegant layout, the pleasant justification, the tender truncation of
run-on text.


Disclaimer: Not everyone likes ansi. Not everyone uses ansi. It is
optional. But, it is not accidental. If you are going to use ansi, please
use it tastefully, and not just because you can. Use ansi colour for the
purpose of either tastefully decorating or emphasizing text. Otherwise,
it's like golf pants. Garish, no matter how you look at them.

For this section, I'm going to simply teach the use of the
ansi() function, which works on both Penn, Tiny, and Mux. There are no
%-substitutions for ansi on Penn, and Tiny and Mux fight over whether to
use %x or %c for ansi colour codes. So, I stick with the basics.
I am also not going to speak much on this, as it is something to
be experimented with before used. Since it is very(almost strictly)
cosmetic, it rounds out this section of the Manual. The use of the
ansi() function imparts colour to what is otherwise drab ascii text. You
cannot recreate the lushness of your favourite 3D game, so please...don't
From help ansi(), you can get a sense of the various colour
combinations that are possible. For each colour listed, there are two
varieties, the base colour and the highlight colour. You can see the
difference by typing: think ansi(c,Cyan) and think ansi(hc,Highlight
Cyan). The second is much more striking, bright, and eye-catching.
The ansi() function should surround the text you are seeking to
change. If we were to apply it to our mywho command, we could list all of
our names in highlight cyan by the following method:


This would change the colour of our names column only, leaving the
sex column as plain text. Feel free to play with the color combinations,
and various effects that ansi has. It is not supported uniformly on all
platforms. Fortunately, a number of clients no longer support flashing
ansi. Remember that potentially anyone could be using your code, and so
you should code for the capabilities of the maximum number of users, not
just what works on /your/ machine.
That is as close to another of my original Rules of Coding as you
are going to get. Code for what the most users will be able to do, not
just what you see on your machine.


This is as close to ascii art as I'm going to get, and I shall
only demonstrate one method of making a header/footer combination, and
then leave you to play with characters on your own to come up with a style
that you like.
It is often visually appealing to display the output of your code
sandwiched between a pleasantly-graphic header and footer that separate
your code's output from the rest of the text on your screen. A sample
header and footer for a mywho would be:

My Who
Bob Will Male
Sara Won't Female
Guest Not set.

Very simplistic, but you see how it provides a definite 'frame'
for your code's output. Quite often, headers and footers get used over and
over by many different commands, so it's best to put them in an attribute
by themselves, and let them be called by many different things. Here, I
will use the repeat() function to create a line of alternating ~^
patterns. Note that there is a %0 in this function, that will serve as the
title of the command being displayed.

&cmdheader obj=[repeat(~^,39)]%R[center(ucstr(%0),78)]%R[repeat(~^,39)]%R

The reason I repeat the ~^ 39 times is that it is two characters
long. 39 x 2 = 78. That's how wide I want my display to be. For my footer,
I will just use that same graphical pattern, making one line. I will put a
%R before it so that I am always ensured that it is going on its own
line. I put a %R at the end of my cmdheader so that I am always ensured
that what comes after the header begins on its own line, as well.

&cmdfooter obj=%R[repeat(~^,39)]

Note that we will have to call these with a u() or an eval() in
order to have the functions and %R evaluate. If you use v() on these, you
will get back precisely what is in the attribute, and nothing more. Now,
we can modify our mywho command just a bit to accomodate these graphical
bits. Et voila:

&cmd_mywho obj=$mywho:@pemit

Run your mywho again, with these graphics around it. Starting to
look more professional all the time, isn't it? So now you've come this
far, and it's up to you to make the choice to go on, or to rest lightly on
your laurels and remain at the level you have achieved thus far. Going
onward involves math, memory registers, and other nastiness. But, it's