macro question

[bren36 <tk...@gmail.com>]

Hi ,

Is there a way that i can return a value from a  velocity macro

My macro looks something like so

#macro(returnField $fieldPath $varName)
#if($fieldPath.subfield)
 $$varName($fieldPath.field.id)
#returnField ($varName $fieldPath.subfield )
#end
#end

Where i need to return $$varName($fieldPath.field.id)

how can i call the returnField macro and assign it to a variable ??????

 
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Re: macro question

[ap...@recks.org]

Reconsidering the question, just use the velocity 1.6 #evaluate directive, see:
  http://velocity.apache.org/engine/releases/velocity-1.6.2/user-guide.html#Evaluate
applied to your example (note the single quotes):
  #evaluate('#set( $returnVal = $varName($fieldPath.field.id)')
  Returned value: $returnVal

Let us know if this worked for you.

:) Christoph

> bren36 wrote:
>> Hi ,
>>
>> Is there a way that i can return a value from a  velocity macro
>>
>> My macro looks something like so
>>
>> #macro(returnField $fieldPath $varName)
>> #if($fieldPath.subfield)
>>  $$varName($fieldPath.field.id)
>> #returnField ($varName $fieldPath.subfield )
>> #end
>> #end
>>
>> Where i need to return $$varName($fieldPath.field.id)
>>
>> how can i call the returnField macro and assign it to a variable ??????
>>
>>  
> 
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Re: macro question

[ap...@recks.org]

Hi,

if the macro returns a string, use the string-interpolation capability:
  #set( $myVar = "#returnField($fieldPath $varName)" )

if the $varname (note the single '$', more on this below) returns an object, I believe you can assign it either to a global variable (depends on the local scope behavior set in the velocity properties - some changes happened here towards release 1.6.2 - needs testing), or to one of the macro parameters (also release 1.6.x/1.7.x changes something here in the pass by reference functionality - needs testing):
  #macro( call $foo )#if($foo)#**##end#end
  #macro( returnField $fieldPath $varName )
    ...
    #set( #myGlobal = $varName($fieldPath.field.id) )
  #end
  ...
  #set( $myGlobal = false )
  #call( "#returnField($fieldPath $varName)" )
  Your macro updated: $myGlobal
or
  #macro( call $foo )#if($foo)#**##end#end
  #macro( returnField $fieldPath $varName $returnVal )
    ...
    #set( #returnVal = $varName($fieldPath.field.id) )
  #end
  ...
  #set( $returnVal = false )
  #call( "#returnField( $fieldPath $varName $returnVal )" )
  Your macro returned: $returnVal

Note 1: the call macro allows calling something but ignores any string output generated within the macro (or a java method call).

Note 2: you cannot do indirect variable access (see $$varName in your example). You could use the #evaluate directive or tool for this.

Note 3: this looks like too much programming in the template, it might be wise to reconsider the architecture. Consider placing the macro functionality into a java pojo tool and call it via the context - results in much cleaner template code:
  #set( $returnVal = $myTool.returnField( $fieldPath $varName )

Kind regards,
Christoph

bren36 wrote:
> Hi ,
> 
> Is there a way that i can return a value from a  velocity macro
> 
> My macro looks something like so
> 
> #macro(returnField $fieldPath $varName)
> #if($fieldPath.subfield)
>  $$varName($fieldPath.field.id)
> #returnField ($varName $fieldPath.subfield )
> #end
> #end
> 
> Where i need to return $$varName($fieldPath.field.id)
> 
> how can i call the returnField macro and assign it to a variable ??????
> 
>  

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