Support fndptn

fixtures/small/aryptn_actual.rb

@@ -10,7 +10,7 @@
 case ["And I shall have some peace there", "for peace", "comes dropping slow"]
 in String,;
   "Dropping from the veils of the morning to where the cricket sings;"
-in Midnight[*]
+in Midnight[*glow]
   "There midnight's all a glimmer, and noon a purple glow,"
 in 1, *, 2
   "And evening full of the linnet's wings."

fixtures/small/aryptn_expected.rb

@@ -10,7 +10,7 @@
 case ["And I shall have some peace there", "for peace", "comes dropping slow"]
 in [String, *]
   "Dropping from the veils of the morning to where the cricket sings;"
-in Midnight[*]
+in Midnight[*glow]
   "There midnight's all a glimmer, and noon a purple glow,"
 in [1, *, 2]
   "And evening full of the linnet's wings."

fixtures/small/fndptn_actual.rb

@@ -0,0 +1,7 @@
+case ["I will arise", "and go now", "for always night and day"]
+in Lake[*, "I hear lake water lapping", "with low sounds by the shore", *waves]
+    <<~YEATS
+        While I stand on the roadway, or on the pavements grey,
+        I hear it in the deep heart's core.
+    YEATS
+end

fixtures/small/fndptn_expected.rb

@@ -0,0 +1,7 @@
+case ["I will arise", "and go now", "for always night and day"]
+in Lake[*, "I hear lake water lapping", "with low sounds by the shore", *waves]
+  <<~YEATS
+    While I stand on the roadway, or on the pavements grey,
+    I hear it in the deep heart's core.
+  YEATS
+end

librubyfmt/src/format.rs

@@ -3402,6 +3402,7 @@ fn format_in_or_else(ps: &mut dyn ConcreteParserState, in_or_else: InOrElse) {
 fn format_pattern(ps: &mut dyn ConcreteParserState, pattern_node: PatternNode) {
     match pattern_node {
         PatternNode::Aryptn(aryptn) => format_aryptn(ps, aryptn),
+        PatternNode::Fndptn(fndptn) => format_fndptn(ps, fndptn),
     }
 }
 
@@ -3419,10 +3420,7 @@ fn format_aryptn(ps: &mut dyn ConcreteParserState, aryptn: Aryptn) {
                 vals.append(&mut pre_star_list.clone());
             }
             if let Some(star) = maybe_star {
-                vals.push(Expression::Ident(Ident::new(
-                    "*".to_string(),
-                    LineCol(star.2.start_line(), 0),
-                )));
+                vals.push(pattern_splat_as_expr(star));
             }
             if let Some(post_star_list) = maybe_post_star_list {
                 vals.append(&mut post_star_list.clone());
@@ -3432,6 +3430,31 @@ fn format_aryptn(ps: &mut dyn ConcreteParserState, aryptn: Aryptn) {
     );
 }
 
+fn format_fndptn(ps: &mut dyn ConcreteParserState, fndptn: Fndptn) {
+    let Fndptn(_, maybe_collection_name, pre_splat, values, post_splat) = fndptn;
+    if let Some(collection_name) = maybe_collection_name {
+        format_var_ref(ps, collection_name);
+    }
+    ps.breakable_of(
+        BreakableDelims::for_array(),
+        Box::new(|ps| {
+            let mut vals = values.clone();
+            vals.insert(0, pattern_splat_as_expr(pre_splat));
+            vals.push(pattern_splat_as_expr(post_splat));
+
+            format_list_like_thing_items(ps, vals, None, false);
+        }),
+    );
+}
+
+fn pattern_splat_as_expr(var_field: VarField) -> Expression {
+    let mut ident = "*".to_string();
+    if let Some(name) = var_field.1 {
+        ident.push_str(name.to_local_string().as_str());
+    }
+    Expression::Ident(Ident::new(ident, LineCol(var_field.2.start_line(), 0)))
+}
+
 pub fn format_retry(ps: &mut dyn ConcreteParserState, r: Retry) {
     format_keyword(
         ps,

librubyfmt/src/ripper_tree_types.rs

@@ -2384,18 +2384,29 @@ pub struct In(
 #[derive(RipperDeserialize, Debug, Clone)]
 pub enum PatternNode {
     Aryptn(Aryptn),
+    Fndptn(Fndptn),
 }
 
-def_tag!(arrayptn_tag, "aryptn");
+def_tag!(aryptn_tag, "aryptn");
 #[derive(Deserialize, Debug, Clone)]
 pub struct Aryptn(
-    pub arrayptn_tag,
+    pub aryptn_tag,
     pub Option<VarRef>,          // Container type, e.g. `in Foo["a", "b"]`
     pub Option<Vec<Expression>>, // list of values before the first *
     pub Option<VarField>,        // "*" pattern
     pub Option<Vec<Expression>>, // list of values the first *
 );
 
+def_tag!(fndptn_tag, "fndptn");
+#[derive(Deserialize, Debug, Clone)]
+pub struct Fndptn(
+    pub fndptn_tag,
+    pub Option<VarRef>,  // Container type, e.g. `in Foo["a", "b"]`
+    pub VarField,        // leading "*" pattern
+    pub Vec<Expression>, // inner values
+    pub VarField,        // trailing "*" pattern
+);
+
 #[derive(RipperDeserialize, Debug, Clone)]
 pub enum WhenOrElse {
     When(When),