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[XTEND] Code generation [message #775657]

Fri, 06 January 2012 13:26

Peter Johnsen

Messages: 60
Registered: January 2012

Member

Hi,

I have a grammar that looks something like this (simplified):

Y:
('optional')? 'X' name = ID ...

In my template I would like to add optional to the generated file if this word
is present in the source file, e.g.:

optional X somename

should yield:

optional X somename

in the generated file as well. However, is it possible to test whether optional is used in the source file? This would probably appear at ??? below.

def compile( Y y )
'''
??? X <<y.name>>
'''

Any idea guys? Or would I need to rewrite the grammar?

Thanks!

[Updated on: Fri, 06 January 2012 13:27]

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Re: [XTEND] Code generation [message #775660 is a reply to message #775657]

Fri, 06 January 2012 13:31

Ingo Meyer

Messages: 162
Registered: July 2009

Senior Member

You can rewrite the grammar to

Y:
(optional ?= 'optional')? 'X' name = ID ...

and you get a boolean feature.

I think getting that information out of the parser/lexer is much more complicated, so this would be the fastest solution if you can change the grammar.

Ingo

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Re: [XTEND] Code generation [message #775681 is a reply to message #775660]

Fri, 06 January 2012 14:10

Peter Johnsen

Messages: 60
Registered: January 2012

Member

Thanks Sir for your ultra-rapid reply! And your solution works excellent! Smile

A small follow-up (not that related though).

I have this rule (again very simplified):

Var:
  name = ('XVar', 'YVar', 'ZVar')

In the template I want to add the value of name to the target file (either of the three alternatives as they appear in the source file), like this:

def compile( Var v )
'''
«v.name»
'''

However, I only get the address to the object of the Var class. The XTend API has a method getName() that returns this name, but I want the name of the name attribute (of the grammar) written to the file, not the name of the object. Any suggestion?

[Updated on: Fri, 06 January 2012 14:11]

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Re: [XTEND] Code generation [message #775717 is a reply to message #775681]

Fri, 06 January 2012 15:22

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

i do not understand this. can you show us a sample model and a sample output you want to have?
if you want to do some reflection/introspection you can ask every EObject for its eClass
and the EClass for its EStructuralFeatures

~Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: [XTEND] Code generation [message #775732 is a reply to message #775717]

Fri, 06 January 2012 15:51

Peter Johnsen

Messages: 60
Registered: January 2012

Member

Hi Christian,

I'll try to exemplify this. It is probably a simple thing for you pros. Smile

First the grammar:

Class:
  '{' ... '}'

Variable:
  'var' name = ID '->' type = ClassOrType

ClassOrType:
  type = [Class] | Type

Type:
  name = ('int' | 'float')

Input file:

class X {}
   
var varA -> int
var varB -> X

Desirable output file:

int varA
X varB

In text, I would like to generate a file where the type of variable is put in front of the variable name. It may be that my grammar is incorrect?

[Updated on: Fri, 06 January 2012 15:53]

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Re: [XTEND] Code generation [message #775743 is a reply to message #775732]

Fri, 06 January 2012 16:04

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

let us say your grammar is a bit "strange since the or (|) has implications on the type hierarchy too in your case

never the less you can test in your case if the ClassOrType is a Type and then ask it for its name or if not for its type and the type for its name

maybe a grammar like:

ClassOrType:
ClassRef | Type;

Type:
name = ('int' | 'float');

ClassRef: type = [Class] ;

makes it more easy for you.

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: [XTEND] Code generation [message #775758 is a reply to message #775743]

Fri, 06 January 2012 16:33

Peter Johnsen

Messages: 60
Registered: January 2012

Member

Splendid! Thanks very much! Smile

Works great now!

Now I only have one small issue to resolve: when the code is generated and added to my target file, unwanted
new lines are introduced. For instance, I get something like this:

op( int param1, 
    float param2,
  )

when it would be cleaner with:

op( int param1, float param2 )

Is there a fix for this?

[Updated on: Fri, 06 January 2012 16:34]

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Re: [XTEND] Code generation [message #775783 is a reply to message #775758]

Fri, 06 January 2012 17:05

Peter Johnsen

Messages: 60
Registered: January 2012

Member

Update: this happens when the compile(...) methods are invoked. How can these new lines be removed? Smile

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Re: [XTEND] Code generation [message #775789 is a reply to message #775758]

Fri, 06 January 2012 17:13

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi you have to format the xtend file right

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: [XTEND] Code generation [message #775803 is a reply to message #775789]

Fri, 06 January 2012 17:39

Peter Johnsen

Messages: 60
Registered: January 2012

Member

I see. But if I have methods for generating operation and parameter code like this:

def compile( Operation o )
'''
(«FOR p : o.params» «p.compile» «ENDFOR»)
'''

def compile( Param p )
'''
«p.type.compile» «p.name»
'''

How can I format it differently so that new lines don't appear in the parameter list?

[Updated on: Fri, 06 January 2012 17:39]

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Re: [XTEND] Code generation [message #775831 is a reply to message #775803]

Fri, 06 January 2012 18:41

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

def compile( Param p )
'''«p.type.compile» «p.name»'''

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: [XTEND] Code generation [message #775856 is a reply to message #775831]

Fri, 06 January 2012 19:55

Peter Johnsen

Messages: 60
Registered: January 2012

Member

Thanks very much for being patient with a xtext/template newbie and your very rapid and correct answers! Have a great weekend! Smile

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