Implement the optional call operator

org.osate.contract.help/markdown/ContractAnnex.md

@@ -357,6 +357,53 @@ val threadsAndProcesses = self.allSubcomponents
   .filter { (subcomponent, name, category) -> subcomponent.isThread || subcomponent.isProcess };
 ```
 
+### Optional Member Calls
+
+The optional member call operator (`?.`) is used on optional types such as `ComponentInstance?` or `FeatureInstance?` to
+call a member on the optional's base type if the optional has a value. Optional member calls take the following form:
+
+```
+<expression>?.<function_name>
+```
+
+The resulting type of an optional member call is always an optional type. If the expression to the left of the operator
+has a value, then the member call is executed and the return value is wrapped in an optional. If the expression to the
+left of the operator does not have a value, then the result of the operation is an empty optional.
+
+This is an example of an optional member call:
+
+```
+val minimum = self#Compute_Execution_Time?.minimum;
+```
+
+An optional member call is syntactic sugar for calling `map` on an optional type. The above example is equivalent to the
+following example:
+
+```
+val minimum = self#Compute_Execution_Time.map { property ->
+  property.minimum
+};
+```
+
+If an optional member call calls a member that itself returns an optional, then the optional member call is syntactic
+sugar for calling `flatMap` instead of `map` on the optional. This is an example of calling a member that returns an
+optional:
+
+```
+val cet_delta = self#Compute_Execution_Time?.getDelta;
+```
+
+The query `cet_delta` has the type `LongWithUnits<AADL_Project::Time_Units>?`. It does not have the type
+`LongWithUnits<AADL_Project::Time_Units>??`.
+
+The above example is equivalent to the following example:
+
+```
+val cet_delta = self#Compute_Execution_Time.flatMap { property ->
+  property.getDelta
+};
+```
+
 ### Types
 
 The query language is statically typed with type inference. Every val statement and lambda parameter has a type which is

org.osate.contract.ide/src-gen/org/osate/contract/ide/contentassist/antlr/ContractParser.java

@@ -81,6 +81,7 @@ private static void init(ImmutableMap.Builder<AbstractElement, String> builder,
 			builder.put(grammarAccess.getSignedRealAccess().getAlternatives_0(), "rule__SignedReal__Alternatives_0");
 			builder.put(grammarAccess.getNumAltAccess().getAlternatives(), "rule__NumAlt__Alternatives");
 			builder.put(grammarAccess.getLanguageAccess().getAlternatives(), "rule__Language__Alternatives");
+			builder.put(grammarAccess.getMemberCallOperatorAccess().getAlternatives(), "rule__MemberCallOperator__Alternatives");
 			builder.put(grammarAccess.getPredefinedAccess().getAlternatives(), "rule__Predefined__Alternatives");
 			builder.put(grammarAccess.getContractLibraryAccess().getGroup(), "rule__ContractLibrary__Group__0");
 			builder.put(grammarAccess.getContractAccess().getGroup(), "rule__Contract__Group__0");
@@ -245,6 +246,7 @@ private static void init(ImmutableMap.Builder<AbstractElement, String> builder,
 			builder.put(grammarAccess.getExpressionAccess().getRightAssignment_1_2(), "rule__Expression__RightAssignment_1_2");
 			builder.put(grammarAccess.getAndExpressionAccess().getRightAssignment_1_2(), "rule__AndExpression__RightAssignment_1_2");
 			builder.put(grammarAccess.getNotExpressionAccess().getOperandAssignment_1_2(), "rule__NotExpression__OperandAssignment_1_2");
+			builder.put(grammarAccess.getCallExpressionAccess().getOperatorAssignment_1_0_1(), "rule__CallExpression__OperatorAssignment_1_0_1");
 			builder.put(grammarAccess.getCallExpressionAccess().getRightAssignment_1_0_2(), "rule__CallExpression__RightAssignment_1_0_2");
 			builder.put(grammarAccess.getCallExpressionAccess().getTypeArgumentAssignment_1_0_3_1(), "rule__CallExpression__TypeArgumentAssignment_1_0_3_1");
 			builder.put(grammarAccess.getCallExpressionAccess().getArgumentAssignment_1_0_4_1(), "rule__CallExpression__ArgumentAssignment_1_0_4_1");

org.osate.contract.ide/src-gen/org/osate/contract/ide/contentassist/antlr/internal/InternalContract.g

@@ -1907,6 +1907,22 @@ finally {
 	restoreStackSize(stackSize);
 }
 
+// Rule MemberCallOperator
+ruleMemberCallOperator
+	@init {
+		int stackSize = keepStackSize();
+	}
+:
+	(
+		{ before(grammarAccess.getMemberCallOperatorAccess().getAlternatives()); }
+		(rule__MemberCallOperator__Alternatives)
+		{ after(grammarAccess.getMemberCallOperatorAccess().getAlternatives()); }
+	)
+;
+finally {
+	restoreStackSize(stackSize);
+}
+
 // Rule Predefined
 rulePredefined
 	@init {
@@ -2532,6 +2548,27 @@ finally {
 	restoreStackSize(stackSize);
 }
 
+rule__MemberCallOperator__Alternatives
+	@init {
+		int stackSize = keepStackSize();
+	}
+:
+	(
+		{ before(grammarAccess.getMemberCallOperatorAccess().getNORMALEnumLiteralDeclaration_0()); }
+		('.')
+		{ after(grammarAccess.getMemberCallOperatorAccess().getNORMALEnumLiteralDeclaration_0()); }
+	)
+	|
+	(
+		{ before(grammarAccess.getMemberCallOperatorAccess().getOPTIONALEnumLiteralDeclaration_1()); }
+		('?.')
+		{ after(grammarAccess.getMemberCallOperatorAccess().getOPTIONALEnumLiteralDeclaration_1()); }
+	)
+;
+finally {
+	restoreStackSize(stackSize);
+}
+
 rule__Predefined__Alternatives
 	@init {
 		int stackSize = keepStackSize();
@@ -6952,9 +6989,9 @@ rule__CallExpression__Group_1_0__1__Impl
 	}
 :
 (
-	{ before(grammarAccess.getCallExpressionAccess().getFullStopKeyword_1_0_1()); }
-	'.'
-	{ after(grammarAccess.getCallExpressionAccess().getFullStopKeyword_1_0_1()); }
+	{ before(grammarAccess.getCallExpressionAccess().getOperatorAssignment_1_0_1()); }
+	(rule__CallExpression__OperatorAssignment_1_0_1)
+	{ after(grammarAccess.getCallExpressionAccess().getOperatorAssignment_1_0_1()); }
 )
 ;
 finally {
@@ -12126,6 +12163,21 @@ finally {
 	restoreStackSize(stackSize);
 }
 
+rule__CallExpression__OperatorAssignment_1_0_1
+	@init {
+		int stackSize = keepStackSize();
+	}
+:
+	(
+		{ before(grammarAccess.getCallExpressionAccess().getOperatorMemberCallOperatorEnumRuleCall_1_0_1_0()); }
+		ruleMemberCallOperator
+		{ after(grammarAccess.getCallExpressionAccess().getOperatorMemberCallOperatorEnumRuleCall_1_0_1_0()); }
+	)
+;
+finally {
+	restoreStackSize(stackSize);
+}
+
 rule__CallExpression__RightAssignment_1_0_2
 	@init {
 		int stackSize = keepStackSize();

org.osate.contract.ide/src-gen/org/osate/contract/ide/contentassist/antlr/internal/InternalContract.tokens

@@ -1,71 +1,72 @@
-'!'=62
-'#'=66
-'&&'=61
-'('=47
-')'=48
+'!'=64
+'#'=67
+'&&'=63
+'('=49
+')'=50
 '*'=21
 '+'=26
-'+=>'=86
-','=49
+'+=>'=87
+','=51
 '-'=27
-'->'=67
-'.'=63
-'..'=78
-':'=55
-'::'=72
-';'=41
-'<'=64
-'<=>'=85
-'='=59
+'->'=68
+'.'=31
+'..'=79
+':'=57
+'::'=73
+';'=43
+'<'=65
+'<=>'=86
+'='=61
 '=>'=24
-'>'=65
-'['=74
-']'=75
+'>'=66
+'?.'=32
+'['=75
+']'=76
 'analysis'=23
-'and'=46
-'applies'=80
-'argument'=42
-'assumptions'=39
-'binding'=83
-'claims'=56
-'classifier'=77
-'component'=54
-'compute'=76
-'constant'=87
-'contract'=33
-'contracts'=57
-'declarations'=45
-'delta'=79
-'domain'=44
-'domains'=36
-'error0'=31
+'and'=48
+'applies'=81
+'argument'=44
+'assumptions'=41
+'binding'=84
+'claims'=58
+'classifier'=78
+'component'=56
+'compute'=77
+'constant'=88
+'contract'=35
+'contracts'=59
+'declarations'=47
+'delta'=80
+'domain'=46
+'domains'=38
+'error0'=33
 'false'=25
-'guarantee'=40
-'implementation'=43
-'in'=82
-'info0'=32
-'input'=38
+'guarantee'=42
+'implementation'=45
+'in'=83
+'info0'=34
+'input'=40
 'invocation'=22
 'java'=29
-'modes'=84
-'not'=51
-'or'=50
-'plan'=53
+'modes'=85
+'not'=53
+'or'=52
+'plan'=55
 'python'=28
-'queries'=37
-'reference'=73
-'root'=69
-'self'=68
+'queries'=39
+'reference'=74
+'root'=70
+'self'=69
 'smt'=30
-'to'=81
-'true'=88
-'use'=70
-'val'=58
-'verification'=52
-'verify'=71
-'{'=34
-'||'=60
-'}'=35
+'to'=82
+'true'=89
+'use'=71
+'val'=60
+'verification'=54
+'verify'=72
+'{'=36
+'||'=62
+'}'=37
 RULE_BASED_INTEGER=18
 RULE_DIGIT=15
 RULE_EXPONENT=16
@@ -151,3 +152,4 @@ T__85=85
 T__86=86
 T__87=87
 T__88=88
+T__89=89