ATL: Atlas Transformation Language Specification of the ... - Eclipse

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Operation Create new object. Format Operand Stack Description New type-encoding … ⇒ …, reference Specification of the ATL Virtual Machine This instruction is used to create new model elements and new composite objects. The type of the object (the element) is resolved from the inline type-encoding argument. If resolution completes successfully, memory for the new object instance is allocated. As a result, type-encoding is popped from the operand stack and replaced by a reference to the allocated object. 7.2 Evolving the asm File Format As the ATL virtual machine instruction set, the asm file format has been primarily designed to encode compiled ATL transformations. At the present time, it is already generic enough to support the encoding of different languages. However, some points may still be improved in order to provide language compilers with even more encoding options. The asm format makes it possible to define a set of fields. These fields are used to store variables. As opposed to the operations, they currently cannot be associated with a specific context. As a matter of fact, they all have to be associated with a default context. In the scope of the ATL language, this context is the ATL module. It may be interesting to allow the declaration of fields in different context. For this purpose, the context in which a field is defined has to be encoded into the asm format. This context may be encoded in the same way that the operation context, as illustrated by the following extract of then asm structure: ... ]> With such a definition, the col field generated for an ATL transformation (see Section N) would be encoded by the following asm structure: Encoding the context of fields into the asm format would provide support for some possible ATL language extensions. We may, for instance, allow ATL programmers to associate attribute helpers with input model elements. These attribute helpers would therefore be encoded in asm as fields that would be defined into the context of input model elements. Finally, the asm format does not encode the operations return type. As this kind of information may be useful, it is possible to include it into the operation definition along with the operation context and parameters. As for the context element, the only required information is the type of the returned value. This information could be encoded in the asm structure in the following way:
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ATL: Atlas Transformation Language
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4.2.2 The pushi instruction........
Page 5 and 6: 1 Introduction Specification of the
Page 7 and 8: Boolean operations: true or false 2
Page 9 and 10: • Removing an element from the ba
Page 11 and 12: Specification of the ATL Virtual Ma
Page 13 and 14: 2.2.1 Preparation Specification of
Page 17 and 18: 2.3.2 Libraries Specification of th
Page 23 and 24: 3.3.1 Local Variables Specification
Page 27 and 28: Push int constant. Format Operand S
Page 29 and 30: Duplicate the top operand stack val
Page 31 and 32: Description Specification of the AT
Page 33 and 34: 4.4.5 The getasm instruction Operat
Page 37 and 38: ]> Specification of the ATL Virtua
Page 39 and 40: ]> Specification of the ATL Vi
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Page 55: 7 Future developments Specification
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ATL: Atlas Transformation Language Specification of the ... - Eclipse

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