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quakeforge/tools/qfcc/doc/qfcc.lyx
Bill Currie 2cfc7a342d [qfcc] Update doc for recent lyx 
And document type expressions to a certain extent. A lot of work needs
to be done as there's a lot of bitrot in the information in the doc (eg,
integer is now int, array declarations, etc).
2024-08-11 20:46:55 +09:00

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#LyX 2.4 created this file. For more info see https://www.lyx.org/
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\leftmargin 1in
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\end_header
\begin_body
\begin_layout Title
The Ruamoko Programming Language
\end_layout
\begin_layout Author
Bill Currie
\begin_inset Formula $\bullet$
\end_inset
Jeff Teunissen
\end_layout
\begin_layout Publishers
QuakeForge Press
\end_layout
\begin_layout Uppertitleback
This manual is free;
you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation;
either version 2 of the License,
or (at your option) any later version.
\begin_inset Newline newline
\end_inset
\begin_inset Newline newline
\end_inset
This manual is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY;
without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
\begin_inset Newline newline
\end_inset
\begin_inset Newline newline
\end_inset
You should have received a copy of the GNU General Public License along with this manual:
if not,
write to:
\begin_inset Newline newline
\end_inset
\begin_inset Newline newline
\end_inset
Free Software Foundation,
Inc.
\begin_inset Newline newline
\end_inset
59 Temple Place - Suite 330
\begin_inset Newline newline
\end_inset
Boston MA 02111-1307
\begin_inset Newline newline
\end_inset
USA
\end_layout
\begin_layout Lowertitleback
Copyright © 2002-2003 Bill Currie and Jeff Teunissen
\end_layout
\begin_layout Standard
\begin_inset CommandInset toc
LatexCommand tableofcontents
\end_inset
\end_layout
\begin_layout Addchap
Preface
\end_layout
\begin_layout Standard
In December 1996,
Id Software released
\emph on
Quake
\emph default
to the world.
It's doubtful that they knew at the time that it would spark a revolution – but such a revolution happened.
To the game industry's surprise,
people were getting the game not just to play it,
but to
\emph on
change
\emph default
it\SpecialChar endofsentence
For the first time,
people could make whole new games based on the Quake engine without having to rewrite the whole game – and in fact you couldn't rewrite the whole game,
because the main source code wasn't available to the general public.
What
\series bold
was
\series default
available was something new – the game wasn't just a game,
it was a virtual machine that had a byte-code instruction set – and it had a compiler that you could use to make new games to run inside that engine.
The language (called
\emph on
QuakeC
\emph default
) was kind of crude,
and the compiler was even more crude – but it was a revolutionary development.
\end_layout
\begin_layout Standard
Now,
let's fast-forward to another December – this time,
three years later.
In another revolutionary move,
Id Software released the source code to the complete Quake engine.
This gave many people the opportunity to do a lot more than just make
\begin_inset Quotes eld
\end_inset
mods
\begin_inset Quotes erd
\end_inset
for Quake.
Instead,
people could make all-new games without using Quake itself.
Many projects started up around this source code,
with many aims\SpecialChar ldots
but one project grew to be the most dominant:
That project is
\emph on
QuakeForge
\emph default
.
\end_layout
\begin_layout Standard
QuakeForge has developed a number of interesting things involving the Quake engine,
but most of them are beyond the scope of this manual.
This manual documents the
\emph on
Ruamoko
\begin_inset Foot
status collapsed
\begin_layout Plain Layout
The name Ruamoko comes from the Maori name for their god of volcanoes and earthquakes.
According to myth,
Ruamoko is not yet born,
and when he shakes inside the Earth-mother,
the world trembles.
\end_layout
\end_inset
\emph default
language,
a language based on Id Software's QuakeC,
but which has been expanded in ways far beyond the original language.
\end_layout
\begin_layout Standard
The idea behind this book is to give new programmers a solid foundation in both of the programming models (procedural and object-oriented) supported by the Ruamoko language,
while giving experienced Ruamoko programmers a complete reference for development of game code.
\end_layout
\begin_layout Standard
\begin_inset FloatList figure
\end_inset
\end_layout
\begin_layout Part
Classical Programming in Ruamoko
\end_layout
\begin_layout Chapter
\begin_inset CommandInset label
LatexCommand label
name "cha:A-Tutorial-Introduction"
\end_inset
Introduction:
Foot,
Meet Mister Rocket Launcher
\end_layout
\begin_layout Standard
Let us begin with a quick introduction to Ruamoko.
Our aim here is to show the basic elements of the language in real programs,
but without getting bogged down in details or rules.
At this point,
we're not even trying to be complete,
or even precise (except that the examples are meant to be correct).
We want to get you as quickly as possible to the point where you can write useful programs,
and to do that we have to concentrate on the basics:
variables and constants,
arithmetic,
flow control,
functions,
and the rudiments of input and output.
We are intentionally leaving out of this chapter features of Ruamoko that are important for writing bigger programs,
or programs to run in an actual Quake engine.
These include entities,
structures,
pointers,
most of the operators,
objects,
and the standard builtin library.
\end_layout
\begin_layout Standard
This approach has its drawbacks.
Most notable is that the complete story on any particular language feature is not found here,
and the brief tutorial,
just by being brief,
may be misleading.
And because the examples don't use the full power of Ruamoko,
they may not be as elegant or concise as they could be;
we
\series bold
have
\series default
tried to minimize these effects,
but be warned.
Another drawback is that later chapters will repeat some of what's presented here.
We hope that the repetition will help more than it annoys.
\end_layout
\begin_layout Standard
In any case,
experienced programmers should be able to get an idea,
from this chapter,
of some of the things that can be done in Ruamoko,
for their own needs.
Beginners should supplement it by writing small,
similar programs of their own.
Both groups can use it as a framework on which to hang the more detailed descriptions that begin in later chapters.
\end_layout
\begin_layout Section
Getting Started
\end_layout
\begin_layout Standard
The best way to learn a new programming language is by writing programs in it.
The first program one writes is almost always the same for all new languages:
print the phrase
\begin_inset Quotes eld
\end_inset
Hello,
world!
\begin_inset Quotes erd
\end_inset
on the screen.
\end_layout
\begin_layout Standard
This is the big hurdle.
To get past it,
you have to be able to create the program text somewhere,
compile it,
load it successfully,
load it,
run it,
and find out where the output went.
With these mechanical details mastered,
everything else is relatively easy.
\end_layout
\begin_layout Standard
\begin_inset Float figure
placement document
alignment document
wide false
sideways false
status collapsed
\begin_layout Plain Layout
\noindent
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100line%"
height "1pt"
\end_inset
\begin_inset ERT
status collapsed
\begin_layout Plain Layout
\backslash
vspace{-1
\backslash
parskip}
\end_layout
\begin_layout Plain Layout
\end_layout
\end_inset
\end_layout
\begin_layout LyX-Code
\begin_inset CommandInset include
LatexCommand verbatiminput
filename "hello.r"
literal "true"
\end_inset
\end_layout
\begin_layout Plain Layout
\noindent
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100line%"
height "1pt"
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
\begin_inset CommandInset label
LatexCommand label
name "cap:Hello-World"
\end_inset
\begin_inset Quotes eld
\end_inset
Hello World
\begin_inset Quotes erd
\end_inset
\end_layout
\end_inset
\end_layout
\end_inset
A Ruamoko program that does this simple task is found in Figure
\begin_inset CommandInset ref
LatexCommand vref
reference "cap:Hello-World"
nolink "false"
\end_inset
.
To run this program,
you first have to compile it.
To compile it,
you need to save the source code into a file (for example,
\family typewriter
hello.r
\family default
),
then compile it with the command
\family typewriter
\series bold
qfcc -o qwaq.dat hello.r
\family default
\series default
.
\end_layout
\begin_layout Standard
If you haven't screwed anything up,
such as omitting a character or misspelling something,
the compilation will proceed.
You should be rewarded with something that looks something like Figure
\begin_inset CommandInset ref
LatexCommand vref
reference "cap:qfcc-output"
nolink "false"
\end_inset
.
\begin_inset Float figure
placement document
alignment document
wide false
sideways false
status collapsed
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\begin_inset CommandInset include
LatexCommand verbatiminput
filename "qfcc-output.txt"
literal "true"
\end_inset
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\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
\family typewriter
\begin_inset CommandInset label
LatexCommand label
name "cap:qfcc-output"
\end_inset
\series bold
qfcc
\family default
\series default
output
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Standard
You run
\family typewriter
qwaq.dat
\family default
by issuing the command
\family typewriter
\series bold
qwaq
\family default
\series default
.
The program should print
\begin_inset Quotes eld
\end_inset
\family typewriter
Hello,
world!
\family default
\begin_inset Quotes erd
\end_inset
to your screen.
\end_layout
\begin_layout Standard
Now,
for some explanations regarding the program itself.
All Ruamoko programs,
regardless of size,
consist mainly of
\emph on
functions
\emph default
and
\emph on
variables
\emph default
.
A function contains statements that tell the compiler what computing operations you want to do,
and variables store values used during the operation of the program.
Ruamoko functions are roughly equivalent to C's functions,
or Pascal's procedures and functions.
Our example is a function called
\family typewriter
main
\family default
.
You can create functions with just about any name you like,
but
\begin_inset Quotes eld
\end_inset
\family typewriter
main
\family default
\begin_inset Quotes erd
\end_inset
is special – program execution begins there
\begin_inset Foot
status collapsed
\begin_layout Plain Layout
This is not precisely true.
When used in a game engine,
there are certain other functions that are called by the engine during the course of a game.
\end_layout
\end_inset
.
This means that every program must have a
\family typewriter
main
\family default
function somewhere.
\end_layout
\begin_layout Standard
The main function will usually call other functions to do its job – some of them you write,
and some of them are provided by the virtual machine your program runs inside.
The first lines of the program (the ones beginning with
\begin_inset Quotes eld
\end_inset
\family typewriter
#include
\family default
\begin_inset Quotes erd
\end_inset
) tell the compiler to include information about the standard variables,
constants,
\emph on
fields
\emph default
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
fields
\end_layout
\end_inset
,
and
\emph on
engine functions
\begin_inset Foot
status collapsed
\begin_layout Plain Layout
also known as
\emph on
builtins
\emph default
.
\end_layout
\end_inset
\emph default
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
functions,
engine
\end_layout
\end_inset
provided by the environment
\begin_inset Foot
status collapsed
\begin_layout Plain Layout
The environment will be described later.
\end_layout
\end_inset
.
\end_layout
\begin_layout Standard
One way of communicating data between functions is for the calling function to provide a list of values,
called
\emph on
arguments
\emph default
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
arguments
\end_layout
\end_inset
,
to the function it calls.
The parentheses after the function's name surround the
\emph on
argument list
\emph default
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
argument list
\end_layout
\end_inset
.
In this example,
main is defined to be a function that expects no arguments,
which is indicated by an empty list:
\begin_inset space ~
\end_inset
\family typewriter
()
\family default
.
\end_layout
\begin_layout Standard
The statements of a function are enclosed in curly braces,
\begin_inset space ~
\end_inset
\family typewriter
{}
\family default
.
The function
\family typewriter
main
\family default
contains only one statement,
\family typewriter
printf ("Hello,
world!
\backslash
n")
\family default
.
This is a
\emph on
function call
\emph default
,
which transfers control from one function to another.
A function is called by giving its name,
followed by a list of arguments enclosed by parentheses,
so this calls the function
\family typewriter
printf
\family default
with the argument
\family typewriter
"Hello,
world!
\backslash
n"
\family default
.
\family typewriter
printf
\family default
is an engine function that prints output,
in this case the string of characters between the quotes.
\end_layout
\begin_layout Standard
A sequence of characters between double quotes,
like
\family typewriter
"Hello,
world!
\backslash
n"
\family default
,
is called a
\emph on
string constant
\emph default
or simply a
\emph on
string
\emph default
.
For the moment,
our only use of strings will be as arguments for
\family typewriter
printf
\family default
and other functions.
\end_layout
\begin_layout Standard
The sequence
\family typewriter
\backslash
n
\family default
in the string is Ruamoko notation for the
\emph on
newline character
\emph default
,
which when printed tells the terminal (or a game client) to advance to the next line in the output.
If you leave out the
\family typewriter
\backslash
n
\family default
,
you will find that there is no advance after the character string is printed.
You must use
\family typewriter
\backslash
n
\family default
to include a newline character in the printf argument;
if you try to insert a newline yourself into the string,
the Ruamoko compiler will give you an error message when you compile the program.
\end_layout
\begin_layout Standard
\begin_inset Float figure
placement document
alignment document
wide false
sideways false
status collapsed
\begin_layout Plain Layout
\noindent
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100line%"
height "1pt"
\end_inset
\begin_inset ERT
status collapsed
\begin_layout Plain Layout
\backslash
vspace{-1
\backslash
parskip}
\end_layout
\begin_layout Plain Layout
\end_layout
\end_inset
\end_layout
\begin_layout LyX-Code
\begin_inset CommandInset include
LatexCommand verbatiminput
filename "hello2.r"
literal "true"
\end_inset
\end_layout
\begin_layout Plain Layout
\noindent
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100line%"
height "1pt"
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
\begin_inset CommandInset label
LatexCommand label
name "cap:A-different-Hello"
\end_inset
A different
\begin_inset Quotes eld
\end_inset
Hello World
\begin_inset Quotes erd
\end_inset
\end_layout
\end_inset
\end_layout
\end_inset
The
\family typewriter
printf()
\family default
function never supplies a newline automatically,
so several calls may be used to build up an output line in stages.
Our first program could just as easily been written as it is in figure
\begin_inset CommandInset ref
LatexCommand vref
reference "cap:A-different-Hello"
nolink "false"
\end_inset
,
and it would have produced identical output.
\end_layout
\begin_layout Standard
Note that
\family typewriter
\backslash
n
\family default
represents only a single character.
An
\emph on
escape character
\emph default
like
\family typewriter
\backslash
n
\family default
gives you a general way to express hard-to-type or invisible characters.
Among the others are
\family typewriter
\backslash
t
\family default
for a tab,
\family typewriter
\backslash
b
\family default
for a backspace,
\family typewriter
\backslash
"
\family default
for a double-quote,
and
\family typewriter
\backslash
\backslash
\family default
for the backslash character itself.
There is a complete list in [section]
\end_layout
\begin_layout Section
Variables and Mathematical Expressions
\end_layout
\begin_layout Standard
\begin_inset Float figure
placement document
alignment document
wide false
sideways false
status collapsed
\begin_layout Plain Layout
\noindent
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100line%"
height "1pt"
\end_inset
\begin_inset ERT
status collapsed
\begin_layout Plain Layout
\backslash
vspace{-1
\backslash
parskip}
\end_layout
\begin_layout Plain Layout
\end_layout
\end_inset
\end_layout
\begin_layout LyX-Code
\begin_inset CommandInset include
LatexCommand verbatiminput
filename "radians.r"
literal "true"
\end_inset
\end_layout
\begin_layout Plain Layout
\noindent
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100line%"
height "1pt"
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
\begin_inset CommandInset label
LatexCommand label
name "cap:Degrees-to-radians"
\end_inset
Degrees to radians
\end_layout
\end_inset
\end_layout
\end_inset
In figure
\begin_inset CommandInset ref
LatexCommand vref
reference "cap:Degrees-to-radians"
nolink "false"
\end_inset
,
we find a simple program uses the formula
\begin_inset Formula $R=D\,\times\,(\frac{\pi}{180})$
\end_inset
to print a table of various angles in both their degrees and radian equivalents.
\end_layout
\begin_layout Standard
The line
\begin_inset Quotes eld
\end_inset
\family typewriter
/* Print a silly conversion table between degrees and radians */
\family default
\begin_inset Quotes erd
\end_inset
and the three parts that say things like
\begin_inset Quotes eld
\end_inset
\family typewriter
// lower limit
\family default
\begin_inset Quotes erd
\end_inset
are
\emph on
comments
\emph default
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
comments
\end_layout
\end_inset
.
Characters between
\family typewriter
/*
\family default
and
\family typewriter
*/
\family default
,
and anything between
\family typewriter
//
\family default
and the next line,
are ignored by the compiler;
they may be used freely to make a program easier for humans to understand.
Comments may appear anywhere a blank space,
or a tab,
or a newline can.
\end_layout
\begin_layout Standard
In Ruamoko,
all variables must be declared before they are used.,
usually at the beginning of the function before any statements.
A declaration
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
declaration,
variable
\end_layout
\end_inset
announces the properties of variables to the compiler;
it consists of a type name and a list of one or more variables,
such as
\end_layout
\begin_layout LyX-Code
float degrees,
radians;
\begin_inset Newline newline
\end_inset
integer lower,
upper,
step;
\end_layout
\begin_layout Standard
The type
\family typewriter
float
\family default
means that the
\family typewriter
degrees
\family default
and
\family typewriter
radians
\family default
variables are floating-point numbers (numbers that can have a fractional part),
and the type
\family typewriter
integer
\family default
means that the
\family typewriter
lower
\family default
,
\family typewriter
upper
\family default
,
and
\family typewriter
step
\family default
variables are integers – that is,
they are whole numbers.
\end_layout
\begin_layout Standard
Unlike C,
in which
\family typewriter
int
\family default
and
\family typewriter
float
\family default
can have different sizes depending on the machine,
Ruamoko variables always have a size that is a multiple of 4 bytes (32 bits).
\end_layout
\begin_layout Standard
Ruamoko provides four basic data types
\begin_inset Index idx
range none
pageformat default
status collapsed
\begin_layout Plain Layout
types,
basic
\end_layout
\end_inset
:
\end_layout
\begin_layout Standard
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="2">
<features tabularvalignment="middle">
<column alignment="left" valignment="top" width="0pt">
<column alignment="left" valignment="top" width="0pt">
<row>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family typewriter
float
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
floating-point numbers
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family typewriter
integer
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
whole numbers,
with a range between -2147483648 and 2147483647.
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family typewriter
string
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
text strings
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family typewriter
vector
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\family roman
\series medium
\shape up
\size normal
\emph off
\bar no
\noun off
\color none
three-dimensional floating-point vectors
\end_layout
\end_inset
</cell>
</row>
</lyxtabular>
\end_inset
\end_layout
\begin_layout Standard
There are more types than just these four,
but this is the list of
\emph on
basic types
\emph default
.
There are also
\emph on
arrays
\emph default
,
\emph on
structures
\emph default
,
and
\emph on
unions
\emph default
of these basic types,
\emph on
pointers
\emph default
to them,
and functions that return them,
all of which we'll meet later.
\end_layout
\begin_layout Standard
The computation in the conversion program begins with the assignment statements
\end_layout
\begin_layout LyX-Code
lower = 0;
\begin_inset Newline newline
\end_inset
upper = 360;
\begin_inset Newline newline
\end_inset
step = 45;
\end_layout
\begin_layout Standard
which set the variables to their initial values.
In Ruamoko,
as in C,
a statement is terminated by the semicolon character.
\end_layout
\begin_layout Standard
Each line of the table is computed in the same manner,
so we use a loop that repeats once per output line;
this is the purpose of the
\family typewriter
while
\family default
loop
\end_layout
\begin_layout LyX-Code
while (degrees <= upper) {
\begin_inset Newline newline
\end_inset
\begin_inset Formula $\vdots$
\end_inset
\begin_inset Newline newline
\end_inset
}
\end_layout
\begin_layout Standard
The
\family typewriter
while
\family default
loop works like this:
The condition in parentheses is tested.
If it is true (if
\family typewriter
degrees
\family default
is less than or equal to
\family typewriter
upper
\family default
),
the body of the loop (the three statements enclosed in the block delimited by the curly braces) is executed.
Then the condition is tested again,
and if it's true again,
the body is executed again.
If and when the condition becomes false (
\family typewriter
degrees
\family default
exceeds
\family typewriter
upper
\family default
),
the loop ends and execution continues at the statement following the loop's end.
Since there are no more statements in the program,
the end of the loop terminates the program.
\end_layout
\begin_layout Standard
The body of a while loop can be one or more statements enclosed in braces (called a block,
or compound statement),
or a single statement without braces,
as in
\end_layout
\begin_layout LyX-Code
while (i < n)
\begin_inset Newline newline
\end_inset
i = i * 2;
\end_layout
\begin_layout Standard
In either case,
we will always indent the statements controlled by the while by one tab stop (which we will show as four spaces),
so you can see at a glance which statements are inside the loop.
The indentation emphasizes the logical structure of the program.
The compiler does not care how your program looks,
but proper indentation and spacing are critical in making programs easy for people (including you) to read.
We recommend writing only one statement per line,
and using blanks around operators to make groupings clear.
The positions of braces is less important,
though you should be warned that many programmers have passionate beliefs about how braces should be used.
We have chosen the so-called
\begin_inset Quotes eld
\end_inset
One True Brace Style
\begin_inset Quotes erd
\end_inset
,
which is the style that Brian Kernighan and Dennis Ritchie used in their book
\bar under
The C Programming Language
\bar default
,
for consistency.
Pick a style that suits you,
and use it consistently in your own work,
but be prepared to adapt to the styles of other programmers when writing as a group.
\end_layout
\begin_layout Standard
Most of the work gets done inside the loop.
The radians for the angle are computed and assigned to the
\family typewriter
radians
\family default
variable using the statement
\end_layout
\begin_layout LyX-Code
radians = degrees * (PI / 180);
\end_layout
\begin_layout Standard
This example also shows a bit more of how
\family typewriter
printf()
\family default
works.
\family typewriter
printf()
\family default
is a general-purpose output formatting function,
which we will describe in detail in [chapter].
Its first argument is a string to be printed,
with each
\family typewriter
%
\family default
indicating where one of the other (second,
third,
and so on) arguments is to be substituted,
and in what form it is to be output.
For instance,
\family typewriter
%f
\family default
specifies a
\family typewriter
float
\family default
argument,
so the statement
\end_layout
\begin_layout LyX-Code
printf("%f
\backslash
t%f
\backslash
n",
degrees,
radians);
\end_layout
\begin_layout Standard
causes the values of the two
\family typewriter
float
\family default
variables
\family typewriter
degrees
\family default
and
\family typewriter
radians
\family default
to be printed,
with a tab (
\family typewriter
\backslash
t
\family default
) between them.
\end_layout
\begin_layout Chapter
Types,
Operators,
and Expressions
\end_layout
\begin_layout Standard
Variables and constants are the basic data units manipulated in a program.
Declarations list the variables to be used,
and state what type they have and perhaps what the initial values for them are.
Operators specify what is to be done to them.
Expressions combine variables and constants to produce new values.
The type of a unit determines the set of values it can have and what operations are permissible for it.
These building blocks are the subject of this chapter.
\end_layout
\begin_layout Section
Variable Names
\end_layout
\begin_layout Standard
Though we didn't say it in Chapter
\begin_inset CommandInset ref
LatexCommand ref
reference "cha:A-Tutorial-Introduction"
nolink "false"
\end_inset
,
there are some restrictions on variable names and symbolic constants.
Names are composed of letters and digits;
the first character must be a letter (the underscore,
\begin_inset Quotes eld
\end_inset
_
\begin_inset Quotes erd
\end_inset
,
counts as a letter – it's often useful for improving the readability of long names).
Don't begin variable names with an underscore,
however,
since functions beginning with _ are reserved for library and engine functions.
Upper-case and lower-case are distinct,
so x and X are two different names.
Traditional practice is to use lower-case or mixed case for variable names,
and all upper-case for
\emph on
symbolic constants
\emph default
,
also known as
\emph on
defines
\emph default
.
Keywords like if,
else,
integer,
float,
etc.
are reserved – you can't use them as variable names.
\end_layout
\begin_layout Section
Constants
\end_layout
\begin_layout Standard
An integer constant like
\family typewriter
5678
\family default
is an integer.
Floating-point constants contain a decimal point (
\family typewriter
123.4
\family default
) or an exponent (
\family typewriter
1e-2
\family default
) or both (
\family typewriter
1.2e3
\family default
).
\end_layout
\begin_layout Standard
The value of an integer can be specified in octal (base 8,
0
\begin_inset Formula $\ldots$
\end_inset
7) or hexadecimal (base 16,
0
\begin_inset Formula $\ldots$
\end_inset
F,
hereafter called
\begin_inset Quotes eld
\end_inset
hex
\begin_inset Quotes erd
\end_inset
) instead of decimal.
A leading
\family typewriter
0
\family default
(zero) on an integer constant means octal;
a leading
\family typewriter
0x
\family default
or
\family typewriter
0X
\family default
means hex.
For example,
decimal 31 can be written as
\family typewriter
037
\family default
in octal,
or
\family typewriter
0x1f
\family default
or
\family typewriter
0X1F
\family default
in hex.
\end_layout
\begin_layout Standard
Certain characters can be represented in string constants by escape sequences like
\family typewriter
\backslash
n
\family default
(newline);
these sequences look like two characters,
but represent only one.
In addition,
an arbitrary byte value can be represented by
\end_layout
\begin_layout LyX-Code
\backslash
o
\end_layout
\begin_layout Standard
where
\family typewriter
o
\family default
is one to three octal digits or by
\end_layout
\begin_layout LyX-Code
\backslash
xh
\end_layout
\begin_layout Standard
where
\family typewriter
h
\family default
is one or more hex digits.
So we might write
\end_layout
\begin_layout LyX-Code
"vtab =
\backslash
013"
\end_layout
\begin_layout Standard
or,
in hex,
\end_layout
\begin_layout LyX-Code
"vtab =
\backslash
x0b"
\end_layout
\begin_layout Standard
The complete set of escape sequences is found in Table
\begin_inset CommandInset ref
LatexCommand ref
reference "cap:Escape-sequences"
nolink "false"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset Float table
placement document
alignment document
wide false
sideways false
status collapsed
\begin_layout Plain Layout
\begin_inset space \hfill{}
\end_inset
\begin_inset Tabular
<lyxtabular version="3" rows="14" columns="2">
<features tabularvalignment="middle">
<column alignment="left" valignment="top" width="0pt">
<column alignment="left" valignment="top" width="0pt">
<row>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
Sequence
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
Description
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
a
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
Alert (bell) character
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
b
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
backspace
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
f
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
form feed
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
n
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
newline
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
r
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
carriage return
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
t
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
tab character
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
\backslash
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
backslash
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
?
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
question mark
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
'
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
single quote
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
"
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
double quote
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
ooo
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
octal number
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
xhh
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
hex number
\end_layout
\end_inset
</cell>
</row>
<row>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
\backslash
^
\end_layout
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" rightline="true" usebox="none">
\begin_inset Text
\begin_layout Plain Layout
alternate character set (toggles)
\end_layout
\end_inset
</cell>
</row>
</lyxtabular>
\end_inset
\begin_inset space \hfill{}
\end_inset
\end_layout
\begin_layout Plain Layout
\begin_inset Caption Standard
\begin_layout Plain Layout
\begin_inset CommandInset label
LatexCommand label
name "cap:Escape-sequences"
\end_inset
Escape sequences
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Chapter
Control Constructs:
Kneel Before Zod
\end_layout
\begin_layout Chapter
Arrays and Pointers:
Pull Pin,
Then Throw
\bar under
GRENADE
\end_layout
\begin_layout Chapter
Breaking Up The Program:
Now Where Did I Put That?
\end_layout
\begin_layout Part
Object-Oriented Programming in Ruamoko
\end_layout
\begin_layout Part
Language Reference
\end_layout
\begin_layout Chapter
Types
\end_layout
\begin_layout Standard
This is currently just new stuff in
\family typewriter
\series bold
qfcc
\family default
\series default
.
\end_layout
\begin_layout Section
New Type Features
\end_layout
\begin_layout Subsection
New Types
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
int
\end_layout
\end_inset
32 bit signed integer
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
id
\end_layout
\end_inset
generic object pointer
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
Class
\end_layout
\end_inset
class object pointer
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
Protocol
\end_layout
\end_inset
protocol object pointer
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
Method
\end_layout
\end_inset
method pointer
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
SEL
\end_layout
\end_inset
selector
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
IMP
\end_layout
\end_inset
message implementation
\end_layout
\begin_layout Standard
\begin_inset Flex Code
status open
\begin_layout Plain Layout
id
\end_layout
\end_inset
,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
Class
\end_layout
\end_inset
,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
Protocol
\end_layout
\end_inset
,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
Method
\end_layout
\end_inset
,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
SEL
\end_layout
\end_inset
and
\begin_inset Flex Code
status open
\begin_layout Plain Layout
IMP
\end_layout
\end_inset
are part of
\family typewriter
\series bold
qfcc
\family default
\series default
's Objective-QC extensions.
\end_layout
\begin_layout Subsection
Enumerators
\end_layout
\begin_layout Standard
as per C
\end_layout
\begin_layout Subsection
Structures
\end_layout
\begin_layout LyX-Code
struct foo {
\begin_inset Newline newline
\end_inset
integer bar;
\begin_inset Newline newline
\end_inset
float baz;
\begin_inset Newline newline
\end_inset
void () func;
\begin_inset Newline newline
\end_inset
};
\end_layout
\begin_layout Standard
Structures with no elements can be declared for making opaque types (particularly useful for engine interface functions).
\end_layout
\begin_layout Subsection
Arrays
\end_layout
\begin_layout LyX-Code
int [13] array;
\end_layout
\begin_layout Subsection
Pointers
\end_layout
\begin_layout Standard
Pointers are declared the same way as arrays,
but with no number in the
\family typewriter
[]
\family default
s.
In fact,
arrays are just pointers with limited (compile-time) bounds checking (constant indices).
\end_layout
\begin_layout Subsection
Complex types
\end_layout
\begin_layout Standard
Complex types can be created by nesting type declarations within
\family typewriter
()
\family default
s.
e.g.:
\end_layout
\begin_layout LyX-Code
(.float) (string name) find_field;
\end_layout
\begin_layout Standard
declares a function (
\family typewriter
find_field
\family default
) taking a string parameter and returning a float field `offset'.
Without the
\family typewriter
()
\family default
s around the
\family typewriter
.float
\family default
,
the declaration would be a function field.
\end_layout
\begin_layout Subsection
\begin_inset Flex Code
status open
\begin_layout Plain Layout
typedef
\end_layout
\end_inset
\end_layout
\begin_layout Standard
By using
\begin_inset Flex Code
status open
\begin_layout Plain Layout
typedef
\end_layout
\end_inset
complex types can be given symbolic names.
e.g.:
\end_layout
\begin_layout LyX-Code
struct foo_s {};
\begin_inset Newline newline
\end_inset
typedef foo_s [] foo_t;
\end_layout
\begin_layout Standard
creates type
\family typewriter
foo_t
\family default
which is a pointer to the structure
\family typewriter
foo_s
\family default
(which happens to be opaque).
\end_layout
\begin_layout Subsection
Variable-argument functions
\end_layout
\begin_layout Standard
Typed parameters preceding the ellipsis are allowed,
e.g.:
\family typewriter
void (string fmt,
\SpecialChar ldots
) printf;
\end_layout
\begin_layout Standard
More importantly,
it is now possible to write vararg functions in QC.
\family typewriter
@argc
\family default
gives the number of parameters passed through the ellipsis and
\family typewriter
@argv
\family default
is an array of vectors representing the parameters passed through
\family typewriter
\SpecialChar ldots
\family default
.
\end_layout
\begin_layout Standard
\series bold
\emph on
Warning:
attempting to pass
\series default
\emph default
\family typewriter
\series bold
\emph on
@argv
\family default
\series default
\emph default
\series bold
\emph on
to a non-engine function will not work.
This is because of changes in how local variables are handled by the compiler.
\end_layout
\begin_layout Subsection
Improved type checking
\end_layout
\begin_layout Standard
Function parameters and return types are are fully checked,
including the number of parameters passed to a function.
Functions with different return types and/or different parameter types or counts are distinct types and mixing them up will cause a type mismatch error.
Similar for pointers to various types.
\end_layout
\begin_layout Section
Type Expressions
\end_layout
\begin_layout Standard
Type expressions allow for more reusable code as they can specify types based on other types and and their attributes.
\end_layout
\begin_layout LyX-Code
int foo[3];
\end_layout
\begin_layout LyX-Code
@vector(float,sizeof(foo)) bar = '3.14 2.72 1.62';
\end_layout
\begin_layout Standard
In the following,
\family typewriter
type
\family default
must be a type (keyword,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\family typewriter
typedef
\end_layout
\end_inset
,
or another type expression) and
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\family typewriter
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
\family typewriter
count
\end_layout
\end_inset
\end_layout
\end_inset
,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\family typewriter
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
\family typewriter
width
\end_layout
\end_inset
\end_layout
\end_inset
,
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\family typewriter
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
\family typewriter
cols
\end_layout
\end_inset
\end_layout
\end_inset
,
\family typewriter
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\family typewriter
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
\family typewriter
rows
\end_layout
\end_inset
\end_layout
\end_inset
\family default
must be constant integral expressions.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\family typewriter
@function(
\family default
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\family typewriter
)
\end_layout
\end_inset
\family default
A function returning
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
but taking no parameters
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@field(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
A field of
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@pointer(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
A pointer to
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@array(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
,[
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
count
\end_layout
\end_inset
])
\end_layout
\end_inset
An array of
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
elements,
optionally sized to
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
count
\end_layout
\end_inset
\end_layout
\end_inset
.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@base(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
The base scalar type for
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
Always
\begin_inset Flex Code
status open
\begin_layout Plain Layout
float
\end_layout
\end_inset
for
\begin_inset Flex Code
status open
\begin_layout Plain Layout
vector
\end_layout
\end_inset
and
\begin_inset Flex Code
status open
\begin_layout Plain Layout
quaternion
\end_layout
\end_inset
.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@vector(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
,
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
width
\end_layout
\end_inset
)
\end_layout
\end_inset
A vector type with the same base type as
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
,
but with the specified width.
Never returns
\begin_inset Flex Code
status open
\begin_layout Plain Layout
vector
\end_layout
\end_inset
or
\begin_inset Flex Code
status open
\begin_layout Plain Layout
quaternion
\end_layout
\end_inset
(returns
\begin_inset Flex Code
status open
\begin_layout Plain Layout
vec3
\end_layout
\end_inset
or
\begin_inset Flex Code
status open
\begin_layout Plain Layout
vec4
\end_layout
\end_inset
instead)
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@matrix(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
,
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
cols
\end_layout
\end_inset
,
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
rows
\end_layout
\end_inset
)
\end_layout
\end_inset
A matrix type with the same base type as
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
but with the specified columns and rows
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@int(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
An integral scalar with the same size as the base type of
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
\begin_inset Flex Code
status open
\begin_layout Plain Layout
int
\end_layout
\end_inset
or
\begin_inset Flex Code
status open
\begin_layout Plain Layout
long
\end_layout
\end_inset
.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@uint(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
An unsigned integral scalar with the same size as the base type of
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
\begin_inset Flex Code
status open
\begin_layout Plain Layout
unsigned int
\end_layout
\end_inset
or
\begin_inset Flex Code
status open
\begin_layout Plain Layout
unsigned long
\end_layout
\end_inset
.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@bool(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
A boolean scalar with the same size as the base type of
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@float(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
A floating point scalar with the same size as the base type of
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
\begin_inset Flex Code
status open
\begin_layout Plain Layout
float
\end_layout
\end_inset
or
\begin_inset Flex Code
status open
\begin_layout Plain Layout
double
\end_layout
\end_inset
.
\end_layout
\begin_layout Standard
The following complement the
\begin_inset Flex Code
status open
\begin_layout Plain Layout
sizeof
\end_layout
\end_inset
keyword:
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@width(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
The number of elements in
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
Always 1 for scalars and matrices,
3 for
\begin_inset Flex Code
status open
\begin_layout Plain Layout
vector
\end_layout
\end_inset
and 4 for
\begin_inset Flex Code
status open
\begin_layout Plain Layout
quaternion
\end_layout
\end_inset
.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@rows(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
The number of rows in
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
Same as
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@width(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
for vectors and scalars.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\begin_inset Flex Code
status open
\begin_layout Plain Layout
@cols(
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
)
\end_layout
\end_inset
The number of columns in
\begin_inset Flex Code
status open
\begin_layout Plain Layout
\begin_inset Flex Noun
status open
\begin_layout Plain Layout
type
\end_layout
\end_inset
\end_layout
\end_inset
.
Always 1 for vectors and scalars:
vectors are column matrices and scalars are essentially 1x1 matrices.
\end_layout
\begin_layout Chapter
Variables
\end_layout
\begin_layout Section
Local variables
\end_layout
\begin_layout Subsubsection
Initialization
\end_layout
\begin_layout Standard
Local variables of basic types can now be initialized when declared.
e,g,
\end_layout
\begin_layout Verse
\family typewriter
local integer elite = 31337;
\end_layout
\begin_layout Subsubsection
Unused variables
\end_layout
\begin_layout Standard
Local variables that are declared but not used produce a warning.
\end_layout
\begin_layout Subsubsection
Uninitialized variables
\end_layout
\begin_layout Standard
Checks are done to ensure that local variables have been initialized before being used.
However,
these checks are not perfect and false positives are very likely in complex code.
Occurrences of false negatives are not known,
but the possibility of their existence remains and any examples of false negatives should be reported as bugs.
\end_layout
\begin_layout Section
Complex global variables
\end_layout
\begin_layout Standard
Global array variables can be initialized using
\family typewriter
= {
\family default
\family typewriter
\emph on
element-list
\family default
\emph default
\family typewriter
};
\family default
.
Element lists may be nested using
\family typewriter
{}
\family default
.
Structures cannot currently be initialized,
but this is a FIXME :)
\end_layout
\begin_layout Section
Magic variables
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@self
\family default
Automagically-declared entity variable the engine will use for
\family typewriter
touch
\family default
and
\family typewriter
think
\family default
functions.
This allows
\family typewriter
self
\family default
to be used as the object hidden parameter in methods.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@this
\family default
Automagically-declared
\family typewriter
id
\family default
field that the engine expects to point to the object associated with the entity.
The engine will use this field,
if it exists,
to set the
\family typewriter
self
\family default
parameter to
\family typewriter
touch
\family default
and
\family typewriter
think
\family default
methods (the engine assumes it's calling a method rather than a function if the @this field is used.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@argc
\family default
Number of parameters passed through
\family typewriter
\SpecialChar ldots
\family default
in vararg functions.
Not valid elsewhere.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@argv
\family default
Array of vectors representing the parameters passed through
\family typewriter
\SpecialChar ldots
\family default
in vararg functions.
Not valid elsewhere.
\end_layout
\begin_layout Chapter
Code constructs
\end_layout
\begin_layout Section
\family typewriter
break
\end_layout
\begin_layout Standard
The
\family typewriter
break
\family default
statement can be used to leave a loop (
\family typewriter
while
\family default
,
\family typewriter
do
\family default
\SpecialChar ldots
\family typewriter
while
\family default
,
or
\family typewriter
for
\family default
) prematurely.
The
\family typewriter
break
\family default
statement is also used to leave a
\family typewriter
switch
\family default
statement.
\end_layout
\begin_layout Section
\family typewriter
continue
\end_layout
\begin_layout Standard
The
\family typewriter
continue
\family default
statement is used to jump to the beginning of a loop.
In
\family typewriter
for
\family default
loops,
the test and post expressions are evaluated before continuing with the loop.
\end_layout
\begin_layout Section
\family typewriter
for
\end_layout
\begin_layout Standard
The
\family typewriter
for
\family default
loop is:
\end_layout
\begin_layout LyX-Code
for (
\emph on
initialization-expression
\emph default
;
\emph on
test-expression
\emph default
;
\emph on
post-expression
\emph default
)
\end_layout
\begin_layout LyX-Code
\emph on
statement
\end_layout
\begin_layout Standard
and is equivalent to
\end_layout
\begin_layout LyX-Code
\emph on
initialization expression
\end_layout
\begin_layout LyX-Code
while (
\emph on
test expression
\emph default
) {
\end_layout
\begin_layout LyX-Code
\emph on
statement
\end_layout
\begin_layout LyX-Code
\emph on
post expression
\end_layout
\begin_layout LyX-Code
}
\end_layout
\begin_layout Section
\family typewriter
switch
\end_layout
\begin_layout Standard
The
\family typewriter
switch
\family default
statement is used to select between multiple code blocks based on the value of an expression.
\end_layout
\begin_layout LyX-Code
switch (
\emph on
test expression
\emph default
) {
\begin_inset Newline newline
\end_inset
case
\emph on
value
\emph default
:
\begin_inset Newline newline
\end_inset
\emph on
optional statements
\begin_inset Newline newline
\end_inset
\emph default
case
\emph on
value
\emph default
:
\begin_inset Newline newline
\end_inset
\emph on
optional statements
\emph default
\begin_inset Newline newline
\end_inset
default:
\begin_inset Newline newline
\end_inset
\emph on
optional statements
\emph default
\begin_inset Newline newline
\end_inset
}
\end_layout
\begin_layout Standard
Code execution starts at the selected
\family typewriter
case
\family default
and continues on to the end of the switch block.
Following
\family typewriter
case
\family default
s do
\emph on
not
\emph default
affect code execution.
If this behavior is not desired,
as is usual,
then a
\family typewriter
break
\family default
statement is required to cause the code to jump to the end of the
\family typewriter
switch
\family default
,
skipping any intervening code.
That is,
just like C.
\end_layout
\begin_layout Subsubsection
\family typewriter
\emph on
test expression
\end_layout
\begin_layout Standard
The test expression may result in a float,
string or integer value.
\end_layout
\begin_layout Subsubsection
\family typewriter
case
\family default
\family typewriter
\emph on
value
\end_layout
\begin_layout Verse
\family typewriter
case
\family default
\family typewriter
\emph on
value
\emph default
:
\end_layout
\begin_layout Standard
The case value may be of any constant type consistent with the test expression of the
\family typewriter
switch
\family default
.
\end_layout
\begin_layout Subsubsection
\family typewriter
default
\end_layout
\begin_layout Standard
If specified,
this is where execution will go when no
\family typewriter
case
\family default
has been selected by the test expression.
If not specified,
and no
\family typewriter
case
\family default
has been selected by the test expression,
the
\family typewriter
switch
\family default
does not execute any code within the block.
\end_layout
\begin_layout Section
Expressions
\end_layout
\begin_layout Subsection
Binary
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
<<
\begin_inset space ~
\end_inset
>>
\family default
bit shift left and right
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
^
\family default
bitwise exclusive or
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
%
\family default
modulus
\end_layout
\begin_layout Subsubsection
Assignment
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
\emph on
op
\emph default
=
\family default
equivalent to
\family typewriter
a = a
\family default
\family typewriter
\emph on
op
\family default
\emph default
\family typewriter
b
\family default
.
\end_layout
\begin_layout Subsection
Unary
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
~
\family default
bitwise not
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
&
\family default
address
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
++
\emph on
e
\emph default
\begin_inset space ~
\end_inset
--
\emph on
e
\family default
\emph default
pre-increment and decrement
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
\emph on
e
\emph default
++
\begin_inset space ~
\end_inset
\emph on
e
\emph default
--
\family default
post-increment and decrement
\end_layout
\begin_layout Subsection
Other
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
\emph on
type
\begin_inset space ~
\end_inset
\emph default
(
\emph on
expr
\emph default
)
\family default
cast expression.
Works only for converting between integer and float types and between pointer types.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
\emph on
expr
\emph default
[
\emph on
expr
\emph default
]
\family default
array indexing.
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
\emph on
expr
\emph default
?
\emph on
expr
\emph default
:
\emph on
expr
\family default
\emph default
C's trinary expression
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
[
\emph on
expr
\emph default
\begin_inset space ~
\end_inset
\emph on
exprs
\emph default
]
\family default
Objective-QC message
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@selector(
\emph on
exprs
\emph default
)
\family default
Objective-QC selector expression
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@protocol(
\emph on
name
\emph default
)
\family default
Objective-QC protocol expression
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@encode(
\emph on
type
\emph default
)
\family default
Objective-QC type encoding expression
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
\family typewriter
@
\emph on
string
\family default
\emph default
Objective-QC string object.
Currently identical to a normal QC string.
\end_layout
\begin_layout Standard
\begin_inset CommandInset index_print
LatexCommand printindex
type "idx"
name "Index"
literal "true"
\end_inset
\end_layout
\end_body
\end_document
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