basic_stmt.htm

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</blockquote>
<blockquote>
<i>Default</i>
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<font color="black"><i>Optional</i></font>. Specifies an indexed property which is array property. A class can have only one <font color="black"><i>default</i></font> property.
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</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Class</b></font> AClass
   <font color="blue"><b>Dim</b></font> fZ = [10, 20, 30, 40, 50]
   <font color="blue"><b>Sub</b></font> <font color="blue"><b>New</b></font>()
   <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
   <font color="blue"><b>Default</b></font> <font color="blue"><b>Property</b></font> Z(I)
     <font color="blue"><b>Get</b></font>
       <font color="blue"><b>return</b></font> fZ(I)
     <font color="blue"><b>End</b></font> <font color="blue"><b>Get</b></font>
     <font color="blue"><b>Set</b></font>
       fZ(I) = Value
     <font color="blue"><b>End</b></font> <font color="blue"><b>Set</b></font>
   <font color="blue"><b>End</b></font> <font color="blue"><b>Property</b></font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Class</b></font>

<font color="blue"><b>Dim</b></font> X = <font color="blue"><b>new</b></font> AClass()
X(1) = 90
<font color="blue"><b>print</b></font> X
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Class Statements">Class Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Structure Statements"><h3>Structure Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Declares the name of a structure type, as well as a definition of the variables, properties, and methods that comprise the structure.
<H4>
Grammar
</H4>
<blockquote>
<pre>
StructureStmt -> <font color="blue"><b>Structure</b></font> Ident 
                 [<font color="blue"><b>Inherits</b></font> Ancestor]
                 MemberStatement /...
                 <font color="blue"><b>End</b></font> <font color="blue"><b>Structure</b></font>
		 
MemberStatement -> DimStmt |
                   SubStmt |
                   PropertyStmt |
</pre>
</blockquote>
<H4>
Arguments
</H4>
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<i>Ident</i>
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Name of structure
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<i>Ancestor</i>
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Optional. Name of <font color="black"><i>ancestor</i></font> structure type.
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</blockquote>
<blockquote>
<i>MemberStatement</i>
<blockquote>
One or more statements that define the variables, properties, and methods of the structure.
</blockquote>
</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Structure</b></font> RandomPoint
  <font color="blue"><b>Dim</b></font> X <font color="blue"><b>As</b></font> <font color="blue"><b>Integer</b></font> = rnd(0, 100)
  <font color="blue"><b>Dim</b></font> Y <font color="blue"><b>As</b></font> <font color="blue"><b>Integer</b></font> = rnd(0, 100)
<font color="blue"><b>End</b></font> <font color="blue"><b>Structure</b></font>

<font color="blue"><b>Structure</b></font> RandomCircle
  <font color="blue"><b>Dim</b></font> R <font color="blue"><b>As</b></font> <font color="blue"><b>Integer</b></font> = rnd(0, 100)
<font color="blue"><b>End</b></font> <font color="blue"><b>Structure</b></font>

<font color="blue"><b>Dim</b></font> C <font color="blue"><b>As</b></font> RandomCircle
<font color="blue"><b>print</b></font> C
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Class Statements">Class Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Throw Statements"><h3>Throw Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Generates an error condition that can be handled by a try...except or try...finally statement.
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Try-catch Statements">Try-catch Statements</a></li>
<li><a href="#Try-finally statements">Try-finally statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Try-catch Statements"><h3>Try-catch Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Exceptions are handled within try...catch statements.
<H4>
Grammar
</H4>
<blockquote>
<pre>
TryExceptStmt -> <font color="blue"><b>Try</b></font> 
                   TryStatements    
                 <font color="blue"><b>Catch</b></font> [Expression]
                   [CatchStatements]
                 <font color="blue"><b>End</b></font> <font color="blue"><b>Try</b></font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>TryStatements</i>
<blockquote>
Required. Statements where an error can occur.
</blockquote>
</blockquote>
<blockquote>
<i>Expression</i>
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Optional. Represents an exception object.
</blockquote>
</blockquote>
<blockquote>
<i>CatchStatements</i>
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Optional. Statements to handle errors occurring in the associated <font color="black"><i>TryStatements</i></font>.
</blockquote>
</blockquote>
The <font color="black"><i>TryStatements</i></font> contain code where an error can occur, while <font color="black"><i>CatchStatements</i></font> contain the code to handle any error that does occur. If an error occurs in the <font color="black"><i>TryStatements</i></font>, program control is passed to <font color="black"><i>CatchStatements</i></font> for processing. The initial value of exception is the value of the error that occurred in <font color="black"><i>TryStatements</i></font>. If no error occurs, <font color="black"><i>CatchStatements</i></font> are never executed.
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Try</b></font>
  <font color="blue"><b>Try</b></font>
    <font color="blue"><b>Throw</b></font> 100
  <font color="blue"><b>Catch</b></font> E
    <font color="blue"><b>print</b></font> <font color="Red">"catch"</font>
    <font color="blue"><b>print</b></font> E
  <font color="blue"><b>End</b></font> <font color="blue"><b>Try</b></font>
<font color="blue"><b>Finally</b></font>
  <font color="blue"><b>print</b></font> <font color="Red">"finally"</font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Try</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Throw Statements">Throw Statements</a></li>
<li><a href="#Try-finally statements">Try-finally statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Try-finally statements"><h3>Try-finally statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Sometimes you want to ensure that specific parts of an operation are completed, whether or not the operation is interrupted by an exception. In these situations, you can use a try...finally statement.
<H4>
Grammar
</H4>
<blockquote>
<pre>
TryFinallyStmt -> <font color="blue"><b>Try</b></font> 
                    TryStatements 
                  <font color="blue"><b>Finally</b></font> 
                    FinallyStatements 
                  <font color="blue"><b>End</b></font> <font color="blue"><b>Try</b></font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>TryStatements</i>
<blockquote>
A sequence of statements (delimited by colons).
</blockquote>
</blockquote>
<blockquote>
<i>FinallyStatements</i>
<blockquote>
Optional. Statements that are unconditionally executed after all other error processing has occurred.
</blockquote>
</blockquote>
The try-finally statement executes the statements in <font color="black"><i>TryStatements</i></font> 
(the try clause). If <font color="black"><i>TryStatements</i></font> finishes without raising exceptions, 
<font color="black"><i>FinallyStatements</i></font> (the finally clause) is executed. If an exception is
raised during execution of <font color="black"><i>TryStatements</i></font>, control is transferred to 
<font color="black"><i>FinallyStatements</i></font>; once <font color="black"><i>FinallyStatements</i></font> finishes executing, the 
exception is re-raised. 

If an exception is raised but not handled in the finally clause, 
that exception is propagated out of the try...finally statement, 
and any exception already raised in the try clause is lost. 
The finally clause should therefore handle all locally raised 
exceptions, so as not to disturb propagation of other exceptions.
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Try</b></font>
  <font color="blue"><b>Try</b></font>
    <font color="blue"><b>Throw</b></font> 100
  <font color="blue"><b>Catch</b></font> E
    <font color="blue"><b>print</b></font> <font color="Red">"catch"</font>
    <font color="blue"><b>print</b></font> E
  <font color="blue"><b>End</b></font> <font color="blue"><b>Try</b></font>
<font color="blue"><b>Finally</b></font>
  <font color="blue"><b>print</b></font> <font color="Red">"finally"</font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Try</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Throw Statements">Throw Statements</a></li>
<li><a href="#Try-catch Statements">Try-catch Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="While Statements"><h3>While Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
The while statement executes its constituent statement repeatedly, testing Condition 
expression before each iteration. As long as 
Condition returns True, execution continues.
<H4>
Grammar
</H4>
<blockquote>
<pre>
WhileStmt -> <font color="blue"><b>While</b></font> Condition 
               Statement
               /...
             <font color="blue"><b>End</b></font> <font color="blue"><b>While</b></font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>Condition</i>
<blockquote>
A Boolean expression. If <font color="black"><i>condition</i></font> is undefined, <font color="black"><i>condition</i></font> is treated as false.
</blockquote>
</blockquote>
<blockquote>
<i>Statement</i>
<blockquote>
Any <font color="black"><i>statement</i></font>
</blockquote>
</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Dim</b></font> i = 0
<font color="blue"><b>While</b></font> i <= 5
  <font color="blue"><b>Print</b></font> i
  i = i + 1
<font color="blue"><b>End</b></font> <font color="blue"><b>While</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Do-loop statements">Do-loop statements</a></li>
<li><a href="#For-Next Statements">For-Next Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="With Statements"><h3>With Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
The with statement is a shorthand for referencing the 
the fields, properties, and methods of an object.
<H4>
Grammar
</H4>
<blockquote>
<pre>
WithStmt -> <font color="blue"><b>With</b></font> Obj /<font color="Red">','</font>...
              Statement
              /...
            <font color="blue"><b>End</b></font> <font color="blue"><b>With</b></font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>Obj</i>
<blockquote>
A variable reference denoting an object.
</blockquote>
</blockquote>
<blockquote>
<i>Statement</i>
<blockquote>
Any <font color="black"><i>statement</i></font>
</blockquote>
</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>With</b></font> Form1 
  .Caption = <font color="Red">"My Form"</font>
  .Height = 200
  .Width = 300
<font color="blue"><b>End</b></font> <font color="blue"><b>With</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Class Statements">Class Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<p>
<HR>
<font size = 1 color ="gray">
Copyright &copy; 1999-2005
VIRT Laboratory. All rights reserved.
</font>
</body>
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