diff --git a/src/imp/gen_map_get.rs b/src/imp/gen_map_get.rs
index e65409ae..f20ecdb4 100644
--- a/src/imp/gen_map_get.rs
+++ b/src/imp/gen_map_get.rs
@@ -107,7 +107,7 @@ impl Expr {
           go(lhs, substitutions, id);
           go(rhs, substitutions, id);
         }
-        Expr::Lst { els } | Expr::Tup { els } => {
+        Expr::Lst { els } | Expr::Tup { els } | Expr::Sup { els } => {
           for el in els {
             go(el, substitutions, id);
           }
diff --git a/src/imp/mod.rs b/src/imp/mod.rs
index 013ada4e..1131232a 100644
--- a/src/imp/mod.rs
+++ b/src/imp/mod.rs
@@ -28,6 +28,8 @@ pub enum Expr {
   Lst { els: Vec<Expr> },
   // "(" ... ")"
   Tup { els: Vec<Expr> },
+  // "{" {els} "}"
+  Sup { els: Vec<Expr> },
   // {name} "{" {kwargs} "}"
   Constructor { name: Name, args: Vec<Expr>, kwargs: Vec<(Name, Expr)> },
   // "[" {term} "for" {bind} "in" {iter} ("if" {cond})? "]"
@@ -53,6 +55,8 @@ pub enum AssignPattern {
   Var(Name),
   // "(" ... ")"
   Tup(Vec<Name>),
+  // "{" ... "}"
+  Sup(Vec<Name>),
   // {name} "[" {expr} "]"
   MapSet(Name, Expr),
 }
diff --git a/src/imp/order_kwargs.rs b/src/imp/order_kwargs.rs
index f24976a5..43c433f6 100644
--- a/src/imp/order_kwargs.rs
+++ b/src/imp/order_kwargs.rs
@@ -104,7 +104,7 @@ impl Expr {
         lhs.order_kwargs(book)?;
         rhs.order_kwargs(book)?;
       }
-      Expr::Lst { els } | Expr::Tup { els } => {
+      Expr::Lst { els } | Expr::Tup { els } | Expr::Sup { els } => {
         for el in els {
           el.order_kwargs(book)?;
         }
diff --git a/src/imp/parser.rs b/src/imp/parser.rs
index 112903bc..47bd6159 100644
--- a/src/imp/parser.rs
+++ b/src/imp/parser.rs
@@ -87,16 +87,18 @@ impl<'a> PyParser<'a> {
       }
       '{' => {
         self.consume("{")?;
-        let mut entries = Vec::new();
-        loop {
-          entries.push(self.parse_map_entry()?);
-          if self.skip_starts_with("}") {
-            break;
-          }
-          self.consume(",")?;
-        }
-        self.consume("}")?;
-        Expr::MapInit { entries }
+        let head = self.parse_infix_or_lambda()?;
+        if self.skip_starts_with(":") { self.parse_map_init(head)? } else { self.parse_sup(head)? }
+        // let mut entries = Vec::new();
+        // loop {
+        //   entries.push(self.parse_map_entry()?);
+        //   if self.skip_starts_with("}") {
+        //     break;
+        //   }
+        //   self.consume(",")?;
+        // }
+        // self.consume("}")?;
+        // Expr::MapInit { entries }
       }
       '[' => self.list_or_comprehension()?,
       '`' => Expr::Num { val: self.parse_symbol()? },
@@ -126,6 +128,39 @@ impl<'a> PyParser<'a> {
     Ok(res)
   }
 
+  fn parse_map_init(&mut self, head: Expr) -> Result<Expr, String> {
+    let mut entries = Vec::new();
+    let map_key = match head {
+      Expr::Num { val } => MapKey(val),
+      _ => self.expected("Number keyword")?,
+    };
+    self.consume(":")?;
+    let val = self.parse_expression()?;
+    entries.push((map_key, val));
+    self.try_consume(",");
+    loop {
+      if self.skip_starts_with("}") {
+        break;
+      }
+      entries.push(self.parse_map_entry()?);
+      self.consume(",")?;
+    }
+    self.consume("}")?;
+    Ok(Expr::MapInit { entries })
+  }
+
+  fn parse_sup(&mut self, head: Expr) -> Result<Expr, String> {
+    let mut els = vec![head];
+    loop {
+      if self.skip_starts_with("}") {
+        break;
+      }
+      els.push(self.parse_infix_or_lambda()?);
+    }
+    self.consume("}")?;
+    Ok(Expr::Sup { els })
+  }
+
   fn data_kwarg(&mut self) -> Result<(Name, Expr), String> {
     let nam = self.parse_bend_name()?;
     self.consume(":")?;
@@ -355,7 +390,7 @@ impl<'a> PyParser<'a> {
   }
 
   fn parse_in_place(&mut self, indent: &mut Indent) -> Result<Stmt, String> {
-    if self.starts_with("(") {
+    if self.starts_with("(") || self.starts_with("{") {
       self.parse_assignment(indent)
     } else {
       let name = self.parse_bend_name()?;
@@ -602,6 +637,9 @@ impl<'a> PyParser<'a> {
       } else {
         Ok(AssignPattern::Tup(binds))
       }
+    } else if self.skip_starts_with("{") {
+      let binds = self.list_like(|p| p.parse_bend_name(), "{", "}", "", false, 2)?;
+      Ok(AssignPattern::Sup(binds))
     } else {
       self.parse_bend_name().map(AssignPattern::Var)
     }
diff --git a/src/imp/to_fun.rs b/src/imp/to_fun.rs
index 7ed9a75d..547009e9 100644
--- a/src/imp/to_fun.rs
+++ b/src/imp/to_fun.rs
@@ -21,6 +21,11 @@ impl AssignPattern {
         fun::Tag::Static,
         names.into_iter().map(|name| fun::Pattern::Var(Some(name))).collect(),
       ),
+      AssignPattern::Sup(names) => fun::Pattern::Fan(
+        fun::FanKind::Dup,
+        fun::Tag::Auto,
+        names.into_iter().map(|name| fun::Pattern::Var(Some(name))).collect(),
+      ),
       AssignPattern::MapSet(..) => unreachable!(),
     }
   }
@@ -119,6 +124,11 @@ impl Expr {
         tag: fun::Tag::Static,
         els: els.into_iter().map(Self::to_fun).collect(),
       },
+      Expr::Sup { els } => fun::Term::Fan {
+        fan: fun::FanKind::Dup,
+        tag: fun::Tag::Auto,
+        els: els.into_iter().map(Self::to_fun).collect(),
+      },
       Expr::Constructor { name, args, kwargs } => {
         assert!(kwargs.is_empty());
         let args = args.into_iter().map(Self::to_fun);