Difference between revisions of "MultiResult"

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=== Examples ===
 
=== Examples ===
  
The following function returns the R, G, B and Alpha components of a color integer, as separate return values.
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This function returns the R, G, B and Alpha components as separate return values given a color integer c.
  
:Function ColorComponents( c: Color ) := <code>
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:Function ColorComponents(c: Color ) := <code>
 
::[[MultiResult]](  
 
::[[MultiResult]](  
 
:::[[BitAnd]]( [ [[BitShift]]( c, 16), 0xFF] ),  
 
:::[[BitAnd]]( [ [[BitShift]]( c, 16), 0xFF] ),  

Latest revision as of 18:42, 4 March 2019

new to Analytica 5.2

Use this function when you want to return more than one distinct value from a User-Defined Function or expression. It is also sometimes convenient in certain looping scenarios when you want to set multiple local variables at the same time.

MultiResult( expr ... )

_( expr ... )

Accepts repeated expressions separated by commas, evaluates the only the ones that are captured by the caller or parent expression, and returns the results as multiple distinct return values. The dimensions of each return value are kept distinct -- they are not combined in any way. MultiResult(a,b,c) and _(a,b,c) are identical in functionality. Stylistically, the MultiResult(...) syntax is generally nicer when used for a UDF return value, whereas the _(...) lends itself to looping scenarios.

Examples

This function returns the R, G, B and Alpha components as separate return values given a color integer c.

Function ColorComponents(c: Color ) :=
MultiResult(
BitAnd( [ BitShift( c, 16), 0xFF] ),
BitAnd( [ BitShift( c, 8), 0xFF] ),
BitAnd( [ c, 0xFF] ),
BitAnd( [ BitShift( c, 24), 0xFF] ) )

You can then capture the separate return values in local values using, e.g.,

Local (r,g,b,a) := ColorComponents( 'Turquoise' );

When you don't need the alpha value,

Local (r,g,b) := ColorComponents( 'Turquoise' );

In this case, the final expression BitAnd( [ BitShift( c, 24), 0xFF] ) in the UDF does not get evaluated.

The next example illustrates its use in a looping construct. Here v is indexed by Time and In1, but the «bodyExpr» does something where it requires v to be indexed only by Time. At the same time, it also needs to know the corresponding index value from In1 for that slice of v.

Local ( vi[Time], i[ ] ) := _( v, In1);
«bodyExpr»

See Also

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