Detecting duplicated components

Add check to detect duplicated components of a record
when parsing a TRLC file.
The Language Reference Manual has been updated accordingly,
and its version has been increased to 3.1

Example:
```
Something duplicated
{
	description = "This is fine!"
	description = "This is the duplicate."
}
```

The behavior of the `Record_Object` class is changed such that the `assign` method only
assigns components to the record if it has not been assigned already.
This is implemented by checking if the field type is different from `Implicit_Null`.

The `Parser` class asks the `Record_Object` if the component is `Implicit_Null`.
If no, then an error is sent to the message handler.

.gitignore

@@ -7,8 +7,11 @@ docs
 *.pyc
 *.egg-info
 .venv/
+venv/
 build
 dist
+launch.json
+settings.json
 
 # EMACS ignores
 *~

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Language support
 
-Up to date with version 3.0 of [TRLC language reference
+Up to date with version 3.1 of [TRLC language reference
 manual](https://bmw-software-engineering.github.io/trlc/lrm.html).
 
 ## Limitations
@@ -30,6 +30,18 @@ generated in the following situations:
 * [TRLC] Fix an UnboundLocalError when missing a term
   in an expression.
 
+* [LRM, TRLC] Add check to detect duplicated components of a record when parsing a TRLC file.
+  Below is an example of a `*.trlc` file demonstrating the new behavior.
+  ```
+  Something duplicated
+  {
+    description = "This is fine!"
+    description = "This is the duplicate."  // will be detected as an error
+  }
+  ```
+  The Language Reference Manual has been updated accordingly, and its version
+  has been increased to 3.1
+
 ### 2.0.0
 
 This new major release includes a number of incompatible

Makefile

@@ -111,3 +111,9 @@ tracing: report.lobster
 	mkdir -p docs
 	lobster-html-report report.lobster --out=docs/tracing.html
 	lobster-ci-report report.lobster
+
+clean-coverage:
+	@rm -rf htmlcov
+	@find . -name '.coverage*' -type f -delete
+	@find . -name '*.pyc' -type f -delete
+	@echo "All .coverage, .coverage.* and *.pyc files deleted."

documentation/LRM.md

@@ -1,6 +1,7 @@
 # TRLC LRM
 
-* [Version 3.0](https://bmw-software-engineering.github.io/trlc/lrm-3.0.html) (Current Stable)
+* [Version 3.1](https://bmw-software-engineering.github.io/trlc/lrm.html) (Current Stable)
+* [Version 3.0](https://bmw-software-engineering.github.io/trlc/lrm-3.0.html) 
 * [Version 2.9](https://bmw-software-engineering.github.io/trlc/lrm-2.9.html)
 * [Version 2.8](https://bmw-software-engineering.github.io/trlc/lrm-2.8.html)
 * [Version 2.7](https://bmw-software-engineering.github.io/trlc/lrm-2.7.html)

language-reference-manual/lrm.trlc

@@ -2,7 +2,7 @@ package LRM
 
 Versioning Version {
   major = 3
-  minor = 0
+  minor = 1
 }
 
 GFDL_License License {
@@ -1775,6 +1775,11 @@ section "Record object declarations" {
               references to R.)*'''
   }
 
+Dynamic_Semantics Single_Value_Assignment {
+  text = '''A value can be assigned to a component of a record object
+            only once.'''
+}
+
   Note Tuple_Checks {
     text = '''The checks for a tuple aggregate are immediately evaluated
               after the last value is parsed.'''

tests-system/rbt-single-value-assignment/foo.rsl

@@ -0,0 +1,6 @@
+package Example
+
+type Requirement {
+  description String
+  critical    Boolean
+}

tests-system/rbt-single-value-assignment/foo.trlc

@@ -0,0 +1,13 @@
+package Example
+
+Requirement safety {
+  critical    = false
+  description = "Is it critical, or is it not?"
+  critical    = true
+}
+
+Requirement duplicated {
+  description = "This is fine"
+  critical    = true
+  description = "This is not fine anymore"
+}

tests-system/rbt-single-value-assignment/output

@@ -0,0 +1,5 @@
+critical    = true
+^^^^^^^^ rbt-single-value-assignment/foo.trlc:6: error: component 'critical' already assigned at line 4
+description = "This is not fine anymore"
+^^^^^^^^^^^ rbt-single-value-assignment/foo.trlc:12: error: component 'description' already assigned at line 10
+Processed 1 model and 1 requirement file and found 2 errors

tests-system/rbt-single-value-assignment/output.brief

@@ -0,0 +1,2 @@
+rbt-single-value-assignment/foo.trlc:6:3: trlc error: component 'critical' already assigned at line 4
+rbt-single-value-assignment/foo.trlc:12:3: trlc error: component 'description' already assigned at line 10

tests-system/rbt-single-value-assignment/output.json

@@ -0,0 +1,5 @@
+critical    = true
+^^^^^^^^ rbt-single-value-assignment/foo.trlc:6: error: component 'critical' already assigned at line 4
+description = "This is not fine anymore"
+^^^^^^^^^^^ rbt-single-value-assignment/foo.trlc:12: error: component 'description' already assigned at line 10
+Processed 1 model and 1 requirement file and found 2 errors

tests-system/rbt-single-value-assignment/output.smtlib

@@ -0,0 +1,5 @@
+critical    = true
+^^^^^^^^ rbt-single-value-assignment/foo.trlc:6: error: component 'critical' already assigned at line 4
+description = "This is not fine anymore"
+^^^^^^^^^^^ rbt-single-value-assignment/foo.trlc:12: error: component 'description' already assigned at line 10
+Processed 1 model and 1 requirement file and found 2 errors

trlc/ast.py

@@ -2999,6 +2999,9 @@ def to_python_dict(self):
         return {name: value.to_python_object()
                 for name, value in self.field.items()}
 
+    def is_component_implicit_null(self, component) -> bool:
+        return not isinstance(self.field[component.name], Implicit_Null)
+
     def assign(self, component, value):
         assert isinstance(component, Composite_Component)
         assert isinstance(value, (Literal,
@@ -3008,6 +3011,9 @@ def assign(self, component, value):
                                   Implicit_Null,
                                   Unary_Expression)), \
                 "value is %s" % value.__class__.__name__
+        if self.is_component_implicit_null(component):
+            raise KeyError(f"Component {component.name} already \
+                           assigned to {self.n_typ.name} {self.name}!")
         self.field[component.name] = value
 
     def dump(self, indent=0):  # pragma: no cover

trlc/parser.py

@@ -1784,6 +1784,7 @@ def parse_record_object_declaration(self):
         # lobster-trace: LRM.Valid_Enumeration_Literals
         # lobster-trace: LRM.Mandatory_Components
         # lobster-trace: LRM.Evaluation_Of_Checks
+        # lobster-trace: LRM.Single_Value_Assignment
 
         r_typ = self.parse_qualified_name(self.default_scope,
                                           ast.Record_Type)
@@ -1810,6 +1811,11 @@ def parse_record_object_declaration(self):
             comp = r_typ.components.lookup(self.mh,
                                            self.ct,
                                            ast.Composite_Component)
+            if obj.is_component_implicit_null(comp):
+                self.mh.error(self.ct.location,
+                              "component '%s' already assigned at line %i" %
+                              (comp.name,
+                               obj.field[comp.name].location.line_no))
             comp.set_ast_link(self.ct)
             if r_typ.is_frozen(comp):
                 self.mh.error(self.ct.location,