basic_stmt.htm

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<blockquote>
One or more <font color="black"><i>statements</i></font> separated by colons; executed if <font color="black"><i>Condition</i></font> is True.
</blockquote>
</blockquote>
<blockquote>
<i>ElseifStatements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> executed if the associated <font color="black"><i>Condition</i></font>-n is True.
</blockquote>
</blockquote>
<blockquote>
<i>ElseStatements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> executed if no previous <font color="black"><i>Condition</i></font> or <font color="black"><i>Condition</i></font>-n expression is True.
</blockquote>
</blockquote>
<H4>
Example 1
</H4>
<pre>
<font color="blue"><b>If</b></font> y = 6 <font color="blue"><b>Then</b></font>
  z = 17
<font color="blue"><b>End</b></font> <font color="blue"><b>If</b></font>
</pre>
<H4>
Example 2
</H4>
<pre>
<font color="blue"><b>If</b></font> x > 0 <font color="blue"><b>Then</b></font>
  s = 1
<font color="blue"><b>ElseIf</b></font> x < 0 <font color="blue"><b>Then</b></font>
  s = -1
<font color="blue"><b>Else</b></font>
  s = 0
<font color="blue"><b>End</b></font> <font color="blue"><b>If</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Select-case Statements">Select-case Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Imports Statements"><h3>Imports Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Imports statements are provided to facilitate the use of namespaces.
<H4>
Grammar
</H4>
<blockquote>
<pre>
ImportsStmt -> <font color="blue"><b>imports</b></font> NamespaceName, /<font color="Red">','</font>... <font color="Red">';'</font>
</pre>
</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Imports</b></font> StdCtrls, Forms

<font color="blue"><b>Dim</b></font> F = <font color="blue"><b>new</b></font> TForm(<font color="blue"><b>NULL</b></font>), B = <font color="blue"><b>new</b></font> TButton(F)

F.Show
B.Parent = F
B.OnClick = <font color="blue"><b>AddressOf</b></font> AHandler
B.Caption = <font color="Red">"Click Me"</font>

<font color="blue"><b>Function</b></font> AHandler(Sender)
  <font color="blue"><b>print</b></font> <font color="Red">"You have clicked the button"</font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Function</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Namespace Statements">Namespace Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Namespace Statements"><h3>Namespace Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Programs are organized using namespaces. You can consider the namespace as a class which contains only static (shared) members.
<H4>
Grammar
</H4>
<blockquote>
<pre>
NamespaceStmt -> <font color="blue"><b>Namespace</b></font> 
                   Statements
                 <font color="blue"><b>End</b></font> <font color="blue"><b>Namespace</b></font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>Statements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> separated by colons.
</blockquote>
</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Namespace</b></font> Shapes
  <font color="blue"><b>Dim</b></font> ShapeCount, ShapeList[100]

  <font color="blue"><b>Sub</b></font> RegisterShape(S)
    ShapeCount += 1
    ShapeList[ShapeCount] = S 
  <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
   
  <font color="blue"><b>Class</b></font> Point
    <font color="blue"><b>Dim</b></font> X, Y
    <font color="blue"><b>Sub</b></font> <font color="blue"><b>New</b></font>(X, Y)
      <font color="blue"><b>Me</b></font>.X = X
      <font color="blue"><b>Me</b></font>.Y = Y
      RegisterShape(<font color="blue"><b>Me</b></font>)
    <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
  <font color="blue"><b>End</b></font> <font color="blue"><b>Class</b></font>
  <font color="blue"><b>Class</b></font> Square
    <font color="blue"><b>Dim</b></font> X1, Y1, X2, Y2
    <font color="blue"><b>Sub</b></font> <font color="blue"><b>New</b></font>(X1, Y1, X2, Y2)
      <font color="blue"><b>Me</b></font>.X1 = X1
      <font color="blue"><b>Me</b></font>.Y1 = Y1
      <font color="blue"><b>Me</b></font>.X2 = X2
      <font color="blue"><b>Me</b></font>.Y2 = Y2
      RegisterShape(<font color="blue"><b>Me</b></font>)
    <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
  <font color="blue"><b>End</b></font> <font color="blue"><b>Class</b></font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Namespace</b></font>

<font color="blue"><b>Dim</b></font> P = Shapes.Point(3, 5)
<font color="blue"><b>print</b></font> P
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Imports Statements">Imports Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Print Statements"><h3>Print Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Prints value of an expression.
<H4>
Grammar
</H4>
<blockquote>
<pre>
PrintStmt -> <font color="blue"><b>print</b></font> Expression /<font color="Red">','</font>...
</pre>
</blockquote>
<H4>
Example
</H4>
<pre>
<font color="blue"><b>print</b></font> 4 * 100 div 7
</pre>
</blockquote>
<a name="Select-case Statements"><h3>Select-case Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Executes one of several groups of statements, depending on the value of an expression.
<H4>
Grammar
</H4>
<blockquote>
<pre>
<font color="blue"><b>Select</b></font> <font color="blue"><b>Case</b></font> TestExpression
   [<font color="blue"><b>Case</b></font> ExpressionList
      [Statements]]
   /...
   [<font color="blue"><b>Case</b></font> <font color="blue"><b>Else</b></font> ExpressionList
      [ElseStatements]]
<font color="blue"><b>End</b></font> <font color="blue"><b>Select</b></font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>TestExpression</i>
<blockquote>
Any numeric or string expression.
</blockquote>
</blockquote>
<blockquote>
<i>ExpressionList</i>
<blockquote>
Delimited list of one or more expressions.
</blockquote>
</blockquote>
<blockquote>
<i>Statements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> executed if <font color="black"><i>testexpression</i></font> matches any part of <font color="black"><i>ExpressionList</i></font>.
</blockquote>
</blockquote>
<blockquote>
<i>ElseStatements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> executed if <font color="black"><i>testexpression</i></font> doesn't match any of the Case clauses.
</blockquote>
</blockquote>
If <font color="black"><i>TestExpression</i></font> matches any Case <font color="black"><i>ExpressionList</i></font> expression, the <font color="black"><i>statements</i></font> following that Case clause are executed up to the next Case clause, or for the last clause, up to End Select. Control then passes to the statement following End Select. If <font color="black"><i>TestExpression</i></font> matches an <font color="black"><i>ExpressionList</i></font> expression in more than one Case clause, only the <font color="black"><i>statements</i></font> following the first match are executed.

The Case Else clause is used to indicate the <font color="black"><i>ElseStatements</i></font> to be executed if no match is found between the <font color="black"><i>TestExpression</i></font> and an <font color="black"><i>expressionlist</i></font> in any of the other Case selections. Although not required, it is a good idea to have a Case Else statement in your Select Case block to handle unforeseen <font color="black"><i>TestExpression</i></font> values. If no Case <font color="black"><i>ExpressionList</i></font> matches <font color="black"><i>TestExpression</i></font> and there is no Case Else statement, execution continues at the statement following End Select.
<H4>
Example
</H4>
<pre>
<font color="blue"><b>Dim</b></font> x = 10
<font color="blue"><b>Select</b></font> <font color="blue"><b>Case</b></font> x
  <font color="blue"><b>Case</b></font> 1 <font color="blue"><b>print</b></font> <font color="Red">"one"</font>
  <font color="blue"><b>Case</b></font> 2 <font color="blue"><b>print</b></font> <font color="Red">"two"</font>
  <font color="blue"><b>Case</b></font> 3 <font color="blue"><b>print</b></font> <font color="Red">"three"</font>
  <font color="blue"><b>Case</b></font> <font color="blue"><b>Else</b></font> <font color="blue"><b>print</b></font> <font color="Red">"else"</font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Select</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#If Statements">If Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Sub Statements"><h3>Sub Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
Declares the name, arguments, and code that form the body of a procedure.
<H4>
Grammar
</H4>
<blockquote>
<pre>
SubStmt -> [<font color="blue"><b>Shared</b></font>] procedure Ident [<font color="Red">'('</font> FormalParam/<font color="Red">','</font>... <font color="Red">')'</font>] <font color="Red">';'</font>
                   Statements 
                 <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
FormalParam -> [<font color="blue"><b>ByRef</b></font>] Parameter
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>Ident</i>
<blockquote>
Name of procedure.
</blockquote>
</blockquote>
<blockquote>
<i>Parameter</i>
<blockquote>
Represents formal <font color="black"><i>parameter</i></font> of procedure. The ByRef keyword indicates that the 
argument is passed by reference.
</blockquote>
</blockquote>
<blockquote>
<i>Statements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> separated by colons.
</blockquote>
</blockquote>
<blockquote>
<i>Shared</i>
<blockquote>
Optional. The class keyword specifies a static (<font color="black"><i>shared</i></font>) method of a class. Can be used only inside of a class body.
</blockquote>
</blockquote>
<H4>
Example 1
</H4>
<pre>
<font color="blue"><b>Sub</b></font> Hanoi(N, X, Y, Z)
  <font color="blue"><b>If</b></font> N > 0 <font color="blue"><b>Then</b></font>
    Hanoi N - 1, X, Z, Y
    <font color="blue"><b>print</b></font> <font color="Red">"Transfer a ring from        "</font> + X + <font color="Red">" to "</font> + Y
    Hanoi N - 1, Z, Y, X
  <font color="blue"><b>End</b></font> <font color="blue"><b>If</b></font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
</pre>
You can use the sub statement inside of a class body. In such case the statement declares a method of the class.
<H4>
Example 2
</H4>
<pre>
<font color="blue"><b>Class</b></font> <font color="blue"><b>MyClass</b></font>
  <font color="blue"><b>Dim</b></font> Z = <font color="Red">"abc"</font>
  <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>Sub</b></font> PrintZ()
    <font color="blue"><b>print</b></font> Z
  <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
  <font color="blue"><b>Shared</b></font> <font color="blue"><b>Sub</b></font> PrintHello()
    <font color="blue"><b>print</b></font> <font color="Red">"Hello "</font>
  <font color="blue"><b>End</b></font> <font color="blue"><b>Sub</b></font>
<font color="blue"><b>End</b></font> <font color="blue"><b>Class</b></font>
</pre>
<H4>
See Also
</H4>
<blockquote>
<ul>
<li><a href="#Class Statements">Class Statements</a></li>
<li><a href="#Function Statements">Function Statements</a></li>
<//ul>
</blockquote>
</blockquote>
<a name="Property Statements"><h3>Property Statements</h3></a>
<!-------------------------------------------------------------------->
<blockquote>
A property, like a field, defines an attribute of an object. But while a field is merely a storage location whose contents can be examined and changed, a property associates specific actions with reading or modifying its data. Properties provide control over access to an object抯 attributes, and they allow attributes to be computed.
<H4>
Grammar
</H4>
<blockquote>
<pre>
PropertyStmt -> [<font color="blue"><b>Default</b></font>] <font color="blue"><b>property</b></font> Ident [ParamList] 
                 [ <font color="blue"><b>Get</b></font>
                    Statements 
                  <font color="blue"><b>End</b></font> <font color="blue"><b>Get</b></font> ]
                 [ <font color="blue"><b>Set</b></font> 
                    Statements
                  <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>
           
ParamList -> <font color="Red">'('</font> Param/<font color="Red">','</font>... <font color="Red">')'</font>
</pre>
</blockquote>
<H4>
Arguments
</H4>
<blockquote>
<i>Ident</i>
<blockquote>
Name of property
</blockquote>
</blockquote>
<blockquote>
<i>Optional</i>
<blockquote>
<font color="black"><i>Optional</i></font>. Parameter of indexed property.
</blockquote>
</blockquote>
<blockquote>
<i>Statements</i>
<blockquote>
One or more <font color="black"><i>statements</i></font> separated by colons.
</blockquote>