[Tams]

This thread is about the EasyLanguage keywords Switch and Case.


Switch/Case (EasyLanguage)


Reserved word used to transfer control to an associated Case or Default statement.


Syntax

Switch ( expression )
Begin
Case case-expression: statements;
Default: statements;
End;

Control passes to the statements whose case-expression matches the value of the switch ( expression ).

The switch statement can include any number of case instances,
but no two case constants within the same switch statement can have the same constant value.


Note Once the statements associated with a matching case are evaluated,
control passes to the end of the switch statement.
This is an implied break and is different than a similar structure found in some other languages that require an explicit break.


Remarks

A single case statement can carry multiple values,
as the following example shows:

Case 1, 2, 3, 4, 5, 6, 20: Value1 = Lowest(Close,3);

Ranges like this are also valid:

Case 1 to 6, 20: Value2 = Highest(High,5);

In both of the above examples,
if case-expression equals any number between 1 and 6 or equal to 20,
a function is called and assigned to a value.

In addition,
logical operators may be used with case statements including: >, <, >=, <=, <> and =.

Case > Average( Close, 50 ): Value1 = Close ;

The “is” keyword is an EasyLanguage skip keyword and can be use for better clarity as in the following:

Case is < Average( High, 75 ): Value1 = High ;


Example

Switch(Value1)  
Begin 

    Case 1 to 5:         
        Value2 = Value2 + 1; 

    Case 10, 20, 30: 
        Value3 = Highest(High,10); 

    Case is > 40: 
        Value3 = Value3 + 1; 

    Default: 
     Value5 = Value5 + 1; 

End;

The above switch statement Increments Value2 when the switch expression (Value1) is a value from 1 to 5;
assigns Value3 to the highest high of 10 bars ago when the switch expression is either 10, 20 or 30;
increments Value4 for all switch expression values above 40;
and increments Value5 for any other values of the switch expression.



Source: EasyLanguage manual

[Tams]

Example...

switch (BarType)
begin

   case 0:
      {this is a Tick or Contract chart}

   case 1:
      {this is a Decond, Minute, or Hourly chart}

   case  2:
      {this is a Daily chart}

   case  3:
      {this is a Weekly chart}

   case 4:
      {this is a Months, Quarters, or Yearly chart}

   case 5: 
      {this is a Points or Changes chart}

end; // end of switch

[Tams]

The above code is a lot more elegant than the traditional way of filtering:

if BarType = 0 then
begin
      {this is a Tick or Contract chart}
end
else
if BarType = 1 then
begin
      {this is a Second, Minute, or Hourly chart}
end
else
if BarType = 2 then
begin
      {this is a Daily chart}
end
else
if BarType = 3 then
begin
      {this is a Weekly chart}
end
else
if BarType = 4 then
begin
      {this is a Months, Quarters, or Yearly chart}
end
else
if BarType = 5 then
begin
      {this is a Points or Changes chart}
end; 

// end of filtering