Extra ATL information Extra ATL information Assigning attributes in - - PowerPoint PPT Presentation

Extra ATL information

• Assigning attributes in ATL rules:

Meta model identification Meta model element identification In/out pattern Attribute assignment

rule example1{ from in: MM1!MetaClassA to

• ut:

MM2!MetaClass1( to

• ut:

MM2!MetaClass1( attr <- in.attr ) }

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Extra ATL information

Assigning references g g

• Three cases:
• Model target element generated by current rule
• Default target model element generated by another rule
• Non-default target model element generated by another

rule

Extra ATL information

• Assigning references:

g g

• Model target element generated by current rule

rule example{ from in: MM1!MetaClass to

• ut1:

MM2!MetaClass1( RefToMetaClass2 <

• ut2

RefToMetaClass2 <- out2 ),

• ut2:

MM2!MetaClass2( ) }

Extra ATL information

• Assigning references

D f l d l l d b h l

• Default target model element generated by another rule

rule example1{ from in: MM1!MetaClassA from in: MM1!MetaClassA to

• ut:

MM2!MetaClass1( RefToMetaClass2 <- in.RefToMetaClassB ) } rule example2{ from in: MM1!MetaClassB to

• ut:

MM2!MetaClass2( ) }

Extra ATL information

• Assigning references

Non defa lt target model element generated b another r le

• Non-default target model element generated by another rule

rule example1{ from in: MM1!MetaClassA to

• ut:

MM2!MetaClass1( RefToMetaClassN <- thisModule.resolveTemp(in.RefToMetaClassB, ‘out_n’) ) } rule example2{ from in: MM1!MetaClassB to

• ut:

MM2!MetaClass1( ),

• ut n:

MM2!MetaClassN( _ ) }

Extra ATL information

• Assigning enums

g g

rule example{ from in: MM1!MetaClassB to t MM2!M t Cl 1( to

• ut:

MM2!MetaClass1( enum <- #”Integer” ) }

• Quotes are only needed in case of reserved words

Rules

• Matched rules

rule rule_name{ from in: MM1!MetaClass(<matching condition>) using{<variable definitions>} to

• ut1:

MM2!MetaClass1( <bindings1> ),

• ut2:

MM2!MetaClass2( <bindings2> <bindings2> ) do{<imperative block>} }

M t h ll d l l t f t

• Matches on all model elements of type MM1!MetaClass,

similar to ASF’s traversal functions

ATL matched rules

• ATL matched rule mechanism provides a mean to

specify the way target model elements must be generated from source model elements.

• A matched rule enables to specify:
• A matched rule enables to specify:

1. which source model element must be matched, 2. the number and the type of the generated target model yp g g elements, and 3. the way these target model elements must be initialized from the matched source elements initialized from the matched source elements

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ATL matched rules

• Each matched rule is identified by its name (rule_name).
• A matched rule name must be unique within an ATL

transformation.

• An ATL matched rule is composed of
• two mandatory sections

− from and to parts.

• two optional sections:

two optional sections:

− using and do parts.

• The different variables that may be declared in the scope of a

rule (the source and target pattern elements and the local rule (the source and target pattern elements and the local variables) must have a unique name.

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Rules

• Lazy matched rules

lazy rule rule_name{ from in: MM1!MetaClass using{<variable definitions>} to

• ut1:

MM2!MetaClass1( <bindings1> ),

• ut2:

MM2!MetaClass2( <bindings2> <bindings2> ) do{<imperative block>} }

G t t t l t f ll t th l

• Generates new target elements for every call to the rule
• Invoked from other rules as follows:

thisModule.rule_name(<model element of type MM1!MetaClass>)

Rules

• Unique lazy matched rules

unique lazy rule rule_name{ from in: MM1!MetaClass using{<variable definitions>} to

• ut1:

MM2!MetaClass1( <bindings1> ),

• ut2:

MM2!MetaClass2( <bindings2> <bindings2> ) do{<imperative block>} }

Al t th t t l t f i

• Always returns the same target elements for a given

source element, i.e., target elements are generated only

• nce per source element

Rules

• Called rules

[entrypoint]? rule rule_name(<parameters>){ using{<variable definitions>} to

• ut1:

MM2!MetaClass1( <bindings1> ),

• ut2:

MM2!MetaClass2( <bindings2> <bindings2> ) do{<imperative block>} }

• For generating target elements from imperative code
• No from clause

Called rules

• Besides matched rules, ATL defines an additional

kind of rules enabling to explicitly generate target model elements from imperative code.

• Except for the entrypoint called rule this kind of
• Except for the entrypoint called rule, this kind of

rules must be explicitly called from an ATL imperative block.

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Called rules

• A called rule is identified by its name (rule_name).
• A called rule name must be unique within an ATL

transformation,

• must not collide with a helper name
• a called rule cannot be called "main".
• A called rule can optionally be declared as the transformation

entrypoint. entrypoint.

• an ATL transformation can include one entrypoint called rule.
• it is implicitly invoked at the beginning of the transformation

execution once the module initialization phase has execution, once the module initialization phase has completed.

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Called rules

• A called rule can accept parameters.
• It is composed of three optional sections:
• the using,
• the to and
• the do sections.
• Compared to a matched rule, a called rule has no from

Compared to a matched rule, a called rule has no from section, and its to section is optional.

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Helpers

• Helper with context

helper context MM!MetaClass def: helper_name(<parameters>): return_type = let <variable definition> in <expression>;

• Invocation:

Invocation:

<model element of type MM!MetaClass>.helper_name(<parameters>)

• The context should never be of a collection type
• Helper without context

p

helper def: helper_name(<parameters>): return_type = let <variable definition> in <expression>;

• Invocation:
• Invocation:

thisModule.helper_name(<parameters>)

• For OCL functions refer to the ATL user guide
• For OCL functions refer to the ATL user guide