HowTos¶

Modeling hierarchical data structures: referencing attributes¶

The idea is to model a structure with attributes (which may again be structures).

struct A {
    val x
}
struct B {
    val a: A
}
struct C {
    val b: B
    val a: A
}
struct D {
    val c: C
    val b1: B
    val a: A
}

instance d: D
reference d.c.b.a.x
reference d.b1.a.x

• Unittest tests/functional/examples/test_hierarchical_data_structures_referencing_attributes.py

Modeling classes and objects: class inheritance¶

Inherited attributes or methods can be accumulated with the textx.scoping.providers.ExtRelativeName scope provider:

• Unittest (classes with pseudo inherited methods) tests/functional/test_scoping/test_metamodel_provider3.py

  • test_metamodel_provider_advanced_test3_inheritance2
  • test_metamodel_provider_advanced_test3_diamond

• Unittest (components with inherited slots) tests/functional/test_scoping/test_inheritance.py

Modeling Wiki-like texts with references inside¶

The idea is to model a string with an arbitrary content and links to other objects (the links are encoded with a special symbol, e.g. "[myref]" or - like in the exmample referenced below "@[myref]"):

ENTRY Hello:    """a way to say hello\@mail (see @[Hi])"""
ENTRY Hi:       """another way to say hello (see @[Hello])"""
ENTRY Salut:    """french "hello" (@[Hello]@[Hi]@[Bonjour]@[Salut]@[Hallo])"""
ENTRY Hallo:    """german way to say hello (see ""@[Hello]"")"""
ENTRY Bonjour:  """another french "\@@[Hello]", see @[Salut]"""
ENTRY NoLink:   """Just text"""
ENTRY Empty:    """"""

• Unittest tests/functional/examples/test_free_text_with_references.py

Referncing a JSON database from within a textX model¶

Here, we link a textX model with a non textX database (could be any database or data structure available in python). If you have, e.g., a DOORS binding, you could also reference such information sources.

• JSON-File "data.json":

  {
    "name": "pierre",
    "gender": "male"
  }
  

• TextX-model:

  import "data.json" as data
  access A1 data.name
  access A2 data.gender
  

• Unittest tests/functional/test_scoping/test_reference_to_nontextx_attribute.py

Referencing global data using full qualified names¶

• Example model:

  package P1 {
      class Part1 {
      }
  }
  package P2 {
      class Part2 {
          attr C2 rec;
      }
      class C2 {
          attr P1.Part1 p1;
          attr Part2 p2a;
          attr P2.Part2 p2b;
      }
  }
  

• Unittest tests/functional/test_scoping/test_full_qualified_name.py

Multi-file models¶

• Unittest (global import) tests/functional/test_scoping/test_global_import_modules.py

• Unittest (explicit import, "importURI") tests/functional/test_scoping/test_import_module.py

• Unittest (explicit import, "importURI" with custom search path) tests/functional/test_scoping/test_import_module_search_path_issue66.py

Multi-metamodel multi-file models¶

Here, we focus on referencing model elements from models based on other textX meta models. These other meta models are typically imported from other python modules (e.g. deployed separately).

In the example referenced below, we simulate three modules with three classes in the unittest. Each class take the role of one module and defines one concrete DSL. These DLS reference each other.

• Model example (types.type) - "Type"-DSL

  type int
  type string
  

• Model example (data_structures.data) - "Data"-DSL

  #include "types.type"
  
  data Point { x: int y: int}
  data City { name: string }
  data Population { count: int}
  

• Model example (data_flow.flow) - "Flow"-DSL

  #include "data_structures.data"
  #include "types.type" // double include, loaded 1x only
  
  algo A1 : Point -> City
  algo A2 : City -> Population
  connect A1 -> A2
  

• Model example (data_flow.flow) - "Flow"-DSL with validation error

  #include "data_structures.data"
  
  algo A1 : Point -> City
  algo A2 : City -> Population
  connect A2 -> A1 // Error, must be A1 -> A2
  

• Unittest tests/functional/test_metamodel/test_multi_metamodel_refs.py

Enable and distinguish float and int values for attributes¶

• Model text:

  x1 = 1
  x2 = -1
  y1 = 1.0
  y2 = 1.1e-2
  y3 = -1.1e+2
  

• Unittest tests/functional/examples/test_modeling_float_int_variables.py

Parsing structures inside arbitrary surrounding text¶

See this StackOverflow question.