CSY/reowolf Changeset - e16722f0d0ac · Centrum Wiskunde & Informatica (CWI)

Changeset - e16722f0d0ac

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Hans-Dieter Hiep - 5 years ago 2020-02-10 15:48:57
hdh@cwi.nl

Lift parser restriction on assignable expressions

3 files changed with 5 insertions and 8 deletions:

src/protocol/parser.rs

testdata/parser/negative/20.txt

testdata/parser/positive/20.pdl

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src/protocol/parser.rs

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@@ @@ -1554,51 +1554,49 @@ impl Visitor for AssignableExpressions { @@
         &mut self,
         h: &mut Heap,
         expr: ConstantExpressionId,
     ) -> VisitorResult {
         if self.assignable {
             self.error(h[expr].position)
         } else {
             Ok(())
+        }
+    }
     fn visit_variable_expression(
         &mut self,
         h: &mut Heap,
         expr: VariableExpressionId,
     ) -> VisitorResult {
         Ok(())
+    }
+}
 struct IndexableExpressions {
     indexable: bool,
+}
 impl IndexableExpressions {
     fn new() -> Self {
         IndexableExpressions { indexable: false }
+    }
     fn new() -> Self {  IndexableExpressions { indexable: false }  }
     fn error(&self, position: InputPosition) -> VisitorResult {
         Err(ParseError::new(position, "Unindexable expression"))
+    }
+}
 impl Visitor for IndexableExpressions {
     fn visit_assignment_expression(
         &mut self,
         h: &mut Heap,
         expr: AssignmentExpressionId,
     ) -> VisitorResult {
         if self.indexable {
             self.error(h[expr].position)
         } else {
             recursive_assignment_expression(self, h, expr)
+        }
+    }
     fn visit_conditional_expression(
         &mut self,
         h: &mut Heap,
         expr: ConditionalExpressionId,
     ) -> VisitorResult {
         let old = self.indexable;
         self.indexable = false;
@@ @@ -1606,52 +1604,54 @@ impl Visitor for IndexableExpressions { @@
         self.indexable = old;
         self.visit_expression(h, h[expr].true_expression)?;
         self.visit_expression(h, h[expr].false_expression)
+    }
     fn visit_binary_expression(&mut self, h: &mut Heap, expr: BinaryExpressionId) -> VisitorResult {
         if self.indexable && h[expr].operation != BinaryOperator::Concatenate {
             self.error(h[expr].position)
         } else {
             recursive_binary_expression(self, h, expr)
+        }
+    }
     fn visit_unary_expression(&mut self, h: &mut Heap, expr: UnaryExpressionId) -> VisitorResult {
         if self.indexable {
             self.error(h[expr].position)
         } else {
             recursive_unary_expression(self, h, expr)
+        }
+    }
     fn visit_indexing_expression(
         &mut self,
         h: &mut Heap,
         expr: IndexingExpressionId,
     ) -> VisitorResult {
         let old = self.indexable;
-        self.indexable = false;
+        self.indexable = true;
         self.visit_expression(h, h[expr].subject)?;
         self.indexable = false;
         self.visit_expression(h, h[expr].index)?;
         self.indexable = old;
-        self.visit_expression(h, h[expr].index)
+        Ok(())
+    }
     fn visit_slicing_expression(
         &mut self,
         h: &mut Heap,
         expr: SlicingExpressionId,
     ) -> VisitorResult {
         let old = self.indexable;
         self.indexable = true;
         self.visit_expression(h, h[expr].subject)?;
         self.indexable = false;
         self.visit_expression(h, h[expr].from_index)?;
         self.visit_expression(h, h[expr].to_index)?;
         self.indexable = old;
         Ok(())
+    }
     fn visit_select_expression(&mut self, h: &mut Heap, expr: SelectExpressionId) -> VisitorResult {
         let old = self.indexable;
         self.indexable = false;
         recursive_select_expression(self, h, expr)?;
         self.indexable = old;
         Ok(())
+    }
     fn visit_array_expression(&mut self, h: &mut Heap, expr: ArrayExpressionId) -> VisitorResult {
         let old = self.indexable;

testdata/parser/negative/20.txt

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deleted file

testdata/parser/positive/20.pdl

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file renamed from testdata/parser/negative/20.pdl to testdata/parser/positive/20.pdl

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