X-Git-Url: http://nitlanguage.org

diff --git a/src/model/model_contract.nit b/src/model/model_contract.nit
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+# 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.
+
+# The abstract concept of a contract in the model
+module model_contract
+
+import model
+import scope
+
+# The root of all contracts
+abstract class MContract
+	super MMethod
+
+	# Is the contract is it already applied on the given `mfacet`
+	fun is_already_applied(mfacet: MFacet): Bool is abstract
+end
+
+# An expect (precondition) contract representation
+class MExpect
+	super MContract
+
+	redef fun is_already_applied(mfacet: MFacet): Bool do return mfacet.has_applied_expect
+end
+
+# The root of all contracts where the call is after the execution of the original method (`invariant` and `ensure`).
+abstract class BottomMContract
+	super MContract
+end
+
+# A ensure (postcondition) representation
+class MEnsure
+	super BottomMContract
+
+	redef fun is_already_applied(mfacet: MFacet): Bool do return mfacet.has_applied_ensure
+end
+
+# A facet contract representation
+# This class is created to keep the information of which method is a contract facet
+class MFacet
+	super MMethod
+
+	# Is there an `expect` contract applied?
+	var has_applied_expect: Bool = false
+
+	# Is there an `ensure` contract applied?
+	var has_applied_ensure: Bool = false
+end
+
+redef class MMethod
+
+	# The contract facet of the method
+	# is representing the method with a contract
+	# This method calls contracts (expect, ensure) and the method
+	var mcontract_facet: nullable MFacet = null
+
+	# The `MExpect` contract if any
+	var mexpect: nullable MExpect = null
+
+	# The `MEnsure` contract if any
+	var mensure: nullable MEnsure = null
+
+	# Build `mensure` if is not exist and return it
+	private fun build_ensure: MEnsure
+	do
+		var m_mensure = self.mensure
+		# build a new `MEnsure` contract
+		if m_mensure == null then m_mensure = new MEnsure(intro_mclassdef, "_ensure_{name}", intro_mclassdef.location, public_visibility)
+		self.mensure = m_mensure
+		return m_mensure
+	end
+
+	# Is there an ensure contract?
+	fun has_ensure: Bool
+	do
+		return self.mensure != null
+	end
+
+	# Build `mexpect` if is not exist and return it
+	private fun build_expect: MExpect
+	do
+		var m_mexpect = self.mexpect
+		# build a new `MExpect` contract
+		if m_mexpect == null then m_mexpect = new MExpect(intro_mclassdef, "_expect_{name}", intro_mclassdef.location, public_visibility)
+		self.mexpect = m_mexpect
+		return m_mexpect
+	end
+
+	# Is there an expect contract?
+	fun has_expect: Bool
+	do
+		return self.mexpect != null
+	end
+
+	# Build `mcontract_facet` if is not exist and return it
+	private fun build_contract_facet: MFacet
+	do
+		var m_mcontract_facet = self.mcontract_facet
+		# build a new `MFacet` contract
+		if m_mcontract_facet == null then m_mcontract_facet = new MFacet(intro_mclassdef, "_contract_{name}", intro_mclassdef.location, public_visibility)
+		self.mcontract_facet = m_mcontract_facet
+		return m_mcontract_facet
+	end
+
+	# Is there an contract facet?
+	fun has_contract_facet: Bool
+	do
+		return self.mcontract_facet != null
+	end
+end