Writing Joystick Code: Part 3: Difference between revisions

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Use Nasal highlighter
m (Update forum links)
m (Use Nasal highlighter)
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In Nasal, we write "then" as "{" and "endif" as "}". Each "action" (or statement) is terminated by a semicolon:
In Nasal, we write "then" as "{" and "endif" as "}". Each "action" (or statement) is terminated by a semicolon:


<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (condition)
if (condition)
{ # the opening curly brace means THEN
{ # the opening curly brace means THEN
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==== An example ====
==== An example ====
Lets say that if x is less than 5 we want to add 2 to it. We write:
Lets say that if x is less than 5 we want to add 2 to it. We write:
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5)  { x = x + 2;  }
if (x < 5)  { x = x + 2;  }
</syntaxhighlight>
</syntaxhighlight>


The more readable way of writing it is
The more readable way of writing it is
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) {
if (x < 5) {
   x = x + 2;
   x = x + 2;
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And we can even omit the braces if there's only one action:
And we can even omit the braces if there's only one action:
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) # no opening brace...
if (x < 5) # no opening brace...
   x = x + 2; # ...so the if statement ends at the first semicolon
   x = x + 2; # ...so the if statement ends at the first semicolon
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If we also want to add 1 to y if the condition is true, we write
If we also want to add 1 to y if the condition is true, we write
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) {
if (x < 5) {
   x = x + 2;
   x = x + 2;
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For example:
For example:


<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) {
if (x < 5) {
   x += 2; # means x = x + 2
   x += 2; # means x = x + 2
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Now lets pretend that we still want to increase x by 2 if it less than 5, and if it is 5 or more we want to add 1 to it. We use else.
Now lets pretend that we still want to increase x by 2 if it less than 5, and if it is 5 or more we want to add 1 to it. We use else.
It looks like this
It looks like this
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) {
if (x < 5) {
   x = x + 2;
   x = x + 2;
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Writing our code properly we get
Writing our code properly we get
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) {
if (x < 5) {
   x = x + 2;
   x = x + 2;
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Easier to understand each condition separately and much less chance of an error.
Easier to understand each condition separately and much less chance of an error.
Our above example would become
Our above example would become
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (x < 5) {
if (x < 5) {
   x = x + 2;
   x = x + 2;
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Lets say that you want something to happen only if the gear is up. But the only property you can read is GearDown. Then you write
Lets say that you want something to happen only if the gear is up. But the only property you can read is GearDown. Then you write
<syntaxhighlight lang="php">
<syntaxhighlight lang="nasal">
if (!GearDown) {
if (!GearDown) {
   action;
   action;