--- /dev/null
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Simple visitor framework for Nit models.
+#
+# This module provides the `ModelVisitor` abstract class and
+# refines the classes of the `MEntity` hierarchy to add visiting related methods.
+#
+# A standard approach on complex visitor is to dispatch the `ModelVisitor::visit` on the
+# entities to do specific things.
+#
+# ~~~nitish
+# class FooVisitor
+# super ModelVisitor
+# redef fun visit(e) do e.foo_visit(self)
+# end
+#
+# redef class MEntity
+# do
+# fun foo_vist(v: FooVisitor) do visit_all(v)
+# end
+#
+# redef class MClass
+# do
+# redef fun foo_visit(v) do
+# print self
+# super
+# end
+# end
+# ~~~
+module model_visitor
+
+import model
+
+# The abstract model visitor template.
+#
+# Specific visitor must implement the `visit` method to perform the work.
+abstract class ModelVisitor
+ # Visit the entity `e`.
+ #
+ # This method setups `current_entity` and call `visit`.
+ # If `e` is null, nothing is done.
+ fun enter_visit(e: nullable MEntity) do
+ if e == null then return
+ var old_entity = current_entity
+ current_entity = e
+ visit(e)
+ current_entity = old_entity
+ end
+
+ # The current visited entity
+ var current_entity: nullable MEntity = null
+
+ # Method to define in specific visitor.
+ #
+ # It should not be called directly but used by `enter_visit`
+ protected fun visit(e: MEntity) is abstract
+
+ # Filter classes and method on the visibility.
+ #
+ # If set, only the classes and method with at least the given
+ # visibility level will be visited.
+ var min_visibility: nullable MVisibility = null is writable
+
+ # Is `visibility` acceptable with regard to `min_visibility`?
+ private fun accept_visitibily(visibility: MVisibility): Bool
+ do
+ var min = min_visibility
+ return min == null or min <= visibility
+ end
+end
+
+redef class MEntity
+ # Call `v.enter_visit` on all nested entities.
+ #
+ # See the specific implementation in the subclasses.
+ fun visit_all(v: ModelVisitor) do end
+end
+
+redef class Model
+ # Visit all the packages of the model.
+ redef fun visit_all(v) do
+ for x in mpackages do v.enter_visit(x)
+ end
+end
+
+redef class MPackage
+ # Visit the root group of the package.
+ redef fun visit_all(v) do
+ v.enter_visit(root)
+ end
+end
+
+redef class MGroup
+ # Visit all the subgroups and modules of the group.
+ redef fun visit_all(v) do
+ for x in in_nesting.direct_smallers do v.enter_visit(x)
+ for x in mmodules do v.enter_visit(x)
+ end
+end
+
+redef class MModule
+ # Visit all the classes and class definitions of the module.
+ #
+ # On class introduction, the `MClass` then the `MClassDef` are visited.
+ # On class refinement, only the `MClassDef` is visited (the `MClass` is visited in an imported module).
+ # On class importation, nothing is visited (the `MClass` and the `MClassDef` are visited in imported modules).
+ redef fun visit_all(v) do
+ for x in mclassdefs do
+ if not v.accept_visitibily(x.mclass.visibility) then return
+ if x.is_intro then v.enter_visit(x.mclass)
+ v.enter_visit(x)
+ end
+ end
+end
+
+redef class MClassDef
+ # Visit all the classes and class definitions of the module.
+ #
+ # On property introduction, the `MProperty` then the `MPropDef` are visited.
+ # On property redefinition, only the `MPropDef` is visited (the `MProperty` is visited in an inherited class).
+ # On property inheritance, nothing is visited (the `MProperty` and the `MPropDef` are visited in inherited classes).
+ redef fun visit_all(v) do
+ for x in mpropdefs do
+ if not v.accept_visitibily(x.mproperty.visibility) then return
+ if x.is_intro then v.enter_visit(x.mproperty)
+ v.enter_visit(x)
+ end
+ end
+end
--- /dev/null
+# This file is part of NIT ( http://www.nitlanguage.org ).
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Example of model_visitor
+module test_model_visitor
+
+import test_phase
+import frontend
+import model_visitor
+import counter
+
+# Example visitor that just count kind of entities.
+class TestModelVisitor
+ super ModelVisitor
+
+ redef fun visit(e) do
+ if not doc_only or e.mdoc != null then
+ cpt.inc(e.class_name)
+ end
+ e.visit_all(self)
+ end
+
+ # Counter of visited entities (by classnames)
+ var cpt = new Counter[String]
+
+ # Do the visitor only count entities with a documentation?
+ var doc_only = false
+end
+
+# The body of the specific work.
+# The main entry point is provided by `test_phase`,
+# This function is then automatically (unless errors where found).
+redef fun do_work(mainmodule, given_mmodules, modelbuilder)
+do
+ var model = modelbuilder.model
+
+ print "All entities:"
+ var v = new TestModelVisitor
+ v.enter_visit(model)
+ v.cpt.print_elements(10)
+
+ print "\nAll non-private entities:"
+ v = new TestModelVisitor
+ v.min_visibility = protected_visibility
+ v.enter_visit(model)
+ v.cpt.print_elements(10)
+
+ print "\nAll documented non-private entities:"
+ v = new TestModelVisitor
+ v.min_visibility = protected_visibility
+ v.doc_only = true
+ v.enter_visit(model)
+ v.cpt.print_elements(10)
+end
nitlanguage / nit.git / commitdiff