+ ruby31.y: pin operator with expression

doc/AST_FORMAT.md

@@ -2112,6 +2112,24 @@ Format:
     ~~~~ expression
 ~~~
 
+### Pin operator with expression
+
+Format:
+
+~~~
+(pin
+  (begin
+    (send
+      (int 2) :+
+      (int 2))))
+"in ^(2 + 2)"
+    ~ selector
+    ~~~~~~~~ expression
+     ~ begin (begin)
+           ~ end (begin)
+     ~~~~~~~ expression (begin)
+~~~
+
 ### Match alternative
 
 Format:

lib/parser/ruby31.y

@@ -1946,6 +1946,7 @@ opt_block_args_tail:
                     }
 
     p_expr_basic: p_value
+                | p_variable
                 | p_const p_lparen p_args rparen
                     {
                       @pattern_hash_keys.pop
@@ -2191,8 +2192,8 @@ opt_block_args_tail:
                     {
                       result = @builder.range_exclusive(val[0], val[1], nil)
                     }
-                | p_variable
                 | p_var_ref
+                | p_expr_ref
                 | p_const
                 | tBDOT2 p_primitive
                     {
@@ -2233,6 +2234,12 @@ opt_block_args_tail:
                       result = @builder.pin(val[0], lvar)
                     }
 
+      p_expr_ref: tCARET tLPAREN expr_value tRPAREN
+                    {
+                      expr = @builder.begin(val[1], val[2], val[3])
+                      result = @builder.pin(val[0], expr)
+                    }
+
          p_const: tCOLON3 cname
                     {
                       result = @builder.const_global(val[0], val[1])

test/test_parser.rb

@@ -10171,4 +10171,53 @@ def test_parser_drops_truncated_parts_of_squiggly_heredoc
       %q{},
       SINCE_2_3)
   end
+
+  def test_pin_expr
+    assert_parses_pattern_match(
+      s(:in_pattern,
+        s(:pin,
+          s(:begin,
+            s(:int, 42))), nil,
+        s(:nil)),
+      %q{in ^(42) then nil},
+      %q{   ~ selector (in_pattern.pin)
+        |   ~~~~~ expression (in_pattern.pin)
+        |    ~ begin (in_pattern.pin.begin)
+        |       ~ end (in_pattern.pin.begin)
+        |    ~~~~ expression (in_pattern.pin.begin)},
+      SINCE_3_1)
+
+    assert_parses_pattern_match(
+      s(:in_pattern,
+        s(:hash_pattern,
+          s(:pair,
+            s(:sym, :foo),
+            s(:pin,
+              s(:begin,
+                s(:int, 42))))), nil,
+        s(:nil)),
+      %q{in { foo: ^(42) } then nil},
+      %q{          ~ selector (in_pattern.hash_pattern.pair.pin)
+        |          ~~~~~ expression (in_pattern.hash_pattern.pair.pin)
+        |           ~ begin (in_pattern.hash_pattern.pair.pin.begin)
+        |              ~ end (in_pattern.hash_pattern.pair.pin.begin)
+        |           ~~~~ expression (in_pattern.hash_pattern.pair.pin.begin)},
+      SINCE_3_1)
+
+    assert_parses_pattern_match(
+      s(:in_pattern,
+        s(:pin,
+          s(:begin,
+            s(:send,
+              s(:int, 0), :+,
+              s(:int, 0)))), nil,
+        s(:nil)),
+      %q{in ^(0+0) then nil},
+      %q{   ~ selector (in_pattern.pin)
+        |   ~~~~~~ expression (in_pattern.pin)
+        |    ~ begin (in_pattern.pin.begin)
+        |        ~ end (in_pattern.pin.begin)
+        |    ~~~~~ expression (in_pattern.pin.begin)},
+      SINCE_3_1)
+  end
 end