Michael Fabain Dirks
110 lines
3.3 KiB
HTML
110 lines
3.3 KiB
HTML
<html>
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<head>
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<meta http-equiv="Content-Type"
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content="text/html; charset=iso-8859-1">
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<title>Language Reference - Variables</title>
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<link rel="stylesheet" href="lang_ref.css" type="text/css">
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</head>
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<body><br>
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<span class="Command"> Variables </span><br>
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<blockquote>
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<p>Variables may be of any basic data type, or a custom type. A variable's type
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is determined by a special character that follows its identifier.<br>
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<br>
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<span class="header"> Variable Types</span></p>
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<blockquote>
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<p>These special characters are called 'type tags' and are: </p>
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</blockquote>
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</blockquote>
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<table width="90%" border="0" cellspacing="0" cellpadding="0" align="center">
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<tr>
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<td>
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<blockquote><br>
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<p> % = For integer variables </p>
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<p> # = For floating point variables </p>
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<p> $ = For string variables </p>
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<p> .{typename} For custom type variables</p>
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</blockquote>
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</td>
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</tr>
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</table>
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<blockquote>
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<blockquote>
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<p> Here are some examples of valid variables: </p>
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</blockquote>
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</blockquote
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>
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<table width="90%" border="0" cellspacing="0" cellpadding="0" align="center">
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<tr>
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<td height="268">
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<p><br>
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</p>
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<blockquote>
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<p>Score%</p>
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<p>Lives% </p>
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<p>x_speed# </p>
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<p>y_speed# </p>
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<p>name$ </p>
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<p>title$ </p>
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<p>ali.Alien </p>
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<p>player.Player</p>
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</blockquote>
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</td>
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</tr>
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</table>
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<blockquote>
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<blockquote>
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<p>The type tag only needs to be added the first time you use a variable,
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after that you can leave the type tag off if you wish. <br>
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<br>
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If you don't supply a type tag the first time a variable is used, the variable
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defaults to an integer. <br>
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</p>
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<p>It is illegal to use the same variable name with a different type. For
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example, if you already have an integer variable called 'name%', it is illegal
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to also have a string variable called 'name$' <br>
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</p>
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</blockquote>
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<p class="header">Setting Variables</p>
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<blockquote>
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<p>The '=' keyword is used to assign a value to a variable. For example: </p>
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<blockquote>
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<p><i>score%=0 </i></p>
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</blockquote>
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<p> ... assigns the value '0' to the integer variable 'score'.</p>
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</blockquote>
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<p><span class="header">Variable Scope</span><br>
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</p>
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<blockquote>
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<p>Variables may also be either '<b>global</b>', or '<b>local</b>'. This refers
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to where in a program a variable may be used.</p>
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<blockquote>
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<p>- <b>Global variables</b> can be used from anywhere in the program. <br>
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<br>
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- <b>Local variables</b> can only be used within the function they are
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created in. </p>
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</blockquote>
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<p> The '<b>Global</b>' keyword is used to define one or more global variables.
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For example: </p>
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<blockquote>
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<p><i>Global Score=0,Lives=3,Player_up=1 </i></p>
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</blockquote>
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<p> ... defines 3 global variables. </p>
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<p> Similarly, '<b>Local</b>' is used to define local variables: </p>
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<blockquote>
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<p><i>Local temp_x=x,temp_y=y </i></p>
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</blockquote>
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<p>If you use a variable without defining it as either local or global, it
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defaults to being local. </p>
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</blockquote>
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</blockquote>
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</body>
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</html> |