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[XPAND2] Learning basic [message #1703397]

Fri, 31 July 2015 09:41

Valentin Edai

Messages: 1
Registered: July 2015

Junior Member

Hi!

I'm learning XPAND2 and I'm trying to do something...
I have a list of elements :

- string name
- double age
- string adress.

In a FOREACH loop, I would like to do something once, just ONCE even if I found the same type after, when the type is a string, once when it's a double. How should I do?

Now, I have something like this but I can't do nothing with it...

 «FOREACH str.member AS mbr-»
            «LET mbr.type.toString() AS type-»
            «LET "true" AS value_str-»                        <==== How can I use this variable? comparing and change value...
                              «IF type == "string"-»
                                     DO SOMETHING()
                               «ENDIF-»
                                «IF type == "double"-»
                                     DO SOMETHING2()
                               «ENDIF-»
             «ENDLET-»
             «ENDLET-»
«ENDFOREACH-»

I'm not sure that my problem is comprehensible but wel...

Edai.

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Re: [XPAND2] Learning basic [message #1703570 is a reply to message #1703397]

Mon, 03 August 2015 08:38

Karsten Thoms

Messages: 762
Registered: July 2009
Location: Dortmund, Germany

Senior Member

You can create a Set and add the already processed types into it:

«LET {}.toSet() AS types»
   «IF !types.contains(type)»
     «types.add(type) -> ""»
            		DO ONCE
     «ENDIF»
«ENDLET»

The expression ->"" will suppress the output of the add operation result into the text.

Note that LET defines a final variable, you can't change the value. It is supposed to be used to evaluate (complex) statements once and cache the result within a block where the result is used multiple times (e.g. collect all fields that meet a certain criteria).

Need professional support for Xtext, EMF, Eclipse IDE?
Go to: http://devhub.karakun.com
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Blog : www.karsten-thoms.de

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