unified: Make switch_case pattern optional; add or_pattern disjunction node

Author: asgerf

unified/extractor/ast_types.yml

@@ -42,6 +42,7 @@ supertypes:
     - name_pattern
     - tuple_pattern
     - constructor_pattern
+    - or_pattern
     - ignore_pattern
     - expr_equality_pattern
     - bulk_importing_pattern
@@ -359,12 +360,12 @@ named:
     case*: switch_case
 
   # A single `case ...:` (or `default:`) entry in a switch.
-  # An entry with multiple `case p1, p2:` patterns has multiple `pattern`s.
-  # A `default:` entry has no patterns.
+  # An entry with multiple `case p1, p2:` patterns uses an `or_pattern`.
+  # A `default:` entry has no pattern.
   # An optional `guard` corresponds to a `where`-clause on the case.
   switch_case:
     modifier*: modifier
-    pattern*: pattern
+    pattern?: pattern
     guard?: expr
     body: block
 
@@ -421,6 +422,11 @@ named:
     constructor: expr_or_type
     element*: pattern_element
 
+  # A disjunction pattern that matches if any of its sub-patterns match.
+  or_pattern:
+    modifier*: modifier
+    pattern*: pattern
+
   # A pattern with an optional associated name.
   pattern_element:
     modifier*: modifier

unified/extractor/src/languages/swift/swift.rs

@@ -654,9 +654,9 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
         ),
         // Switch entry with patterns and body
         rule!(
-            (switch_entry pattern: (switch_pattern pattern: @pats)* statement: _* @body)
+            (switch_entry pattern: (switch_pattern pattern: @pats)+ statement: _* @body)
             =>
-            (switch_case pattern: {..pats} body: (block stmt: {..body}))
+            (switch_case pattern: (or_pattern pattern: {..pats}) body: (block stmt: {..body}))
         ),
         // Switch entry: default case (no patterns)
         rule!(

unified/extractor/tests/corpus/swift/control-flow.txt

@@ -559,8 +559,10 @@ top_level
                         name_expr
                           identifier: identifier "print"
               pattern:
-                expr_equality_pattern
-                  expr: int_literal "1"
+                or_pattern
+                  pattern:
+                    expr_equality_pattern
+                      expr: int_literal "1"
             switch_case
               body:
                 block
@@ -573,10 +575,12 @@ top_level
                         name_expr
                           identifier: identifier "print"
               pattern:
-                expr_equality_pattern
-                  expr: int_literal "2"
-                expr_equality_pattern
-                  expr: int_literal "3"
+                or_pattern
+                  pattern:
+                    expr_equality_pattern
+                      expr: int_literal "2"
+                    expr_equality_pattern
+                      expr: int_literal "3"
             switch_case
               body:
                 block
@@ -699,16 +703,18 @@ top_level
                         name_expr
                           identifier: identifier "print"
               pattern:
-                constructor_pattern
-                  element:
-                    pattern_element
-                      pattern:
-                        name_pattern
-                          identifier: identifier "r"
-                  constructor:
-                    member_access_expr
-                      base: inferred_type_expr "."
-                      member: identifier "circle"
+                or_pattern
+                  pattern:
+                    constructor_pattern
+                      element:
+                        pattern_element
+                          pattern:
+                            name_pattern
+                              identifier: identifier "r"
+                      constructor:
+                        member_access_expr
+                          base: inferred_type_expr "."
+                          member: identifier "circle"
             switch_case
               body:
                 block
@@ -723,16 +729,18 @@ top_level
                         name_expr
                           identifier: identifier "print"
               pattern:
-                constructor_pattern
-                  element:
-                    pattern_element
-                      pattern:
-                        name_pattern
-                          identifier: identifier "s"
-                  constructor:
-                    member_access_expr
-                      base: inferred_type_expr "."
-                      member: identifier "square"
+                or_pattern
+                  pattern:
+                    constructor_pattern
+                      element:
+                        pattern_element
+                          pattern:
+                            name_pattern
+                              identifier: identifier "s"
+                      constructor:
+                        member_access_expr
+                          base: inferred_type_expr "."
+                          member: identifier "square"
           value:
             name_expr
               identifier: identifier "shape"
@@ -844,17 +852,19 @@ top_level
                         name_expr
                           identifier: identifier "print"
               pattern:
-                constructor_pattern
-                  element:
-                    pattern_element
-                      key: identifier "isAcknowledged"
-                      pattern:
-                        expr_equality_pattern
-                          expr: boolean_literal "false"
-                  constructor:
-                    member_access_expr
-                      base: inferred_type_expr "."
-                      member: identifier "implicit"
+                or_pattern
+                  pattern:
+                    constructor_pattern
+                      element:
+                        pattern_element
+                          key: identifier "isAcknowledged"
+                          pattern:
+                            expr_equality_pattern
+                              expr: boolean_literal "false"
+                      constructor:
+                        member_access_expr
+                          base: inferred_type_expr "."
+                          member: identifier "implicit"
             switch_case
               body:
                 block
@@ -869,19 +879,21 @@ top_level
                         name_expr
                           identifier: identifier "print"
               pattern:
-                constructor_pattern
-                  element:
-                    pattern_element
-                      key: identifier "threadRowId"
-                      pattern: ignore_pattern "_"
-                    pattern_element
-                      pattern:
-                        name_pattern
-                          identifier: identifier "rowId"
-                  constructor:
-                    member_access_expr
-                      base: inferred_type_expr "."
-                      member: identifier "thread"
+                or_pattern
+                  pattern:
+                    constructor_pattern
+                      element:
+                        pattern_element
+                          key: identifier "threadRowId"
+                          pattern: ignore_pattern "_"
+                        pattern_element
+                          pattern:
+                            name_pattern
+                              identifier: identifier "rowId"
+                      constructor:
+                        member_access_expr
+                          base: inferred_type_expr "."
+                          member: identifier "thread"
           value:
             name_expr
               identifier: identifier "x"