diff --git a/src/frontend.rs b/src/frontend.rs
index a237bd4..f9bc00e 100644
--- a/src/frontend.rs
+++ b/src/frontend.rs
@@ -3,6 +3,7 @@ use std::collections::BTreeMap;
 use std::fmt::Write;
 
 use super::parser;
+use super::parser::block_expression::BlockExpr;
 use crate::rtlil;
 pub use callable::{Callable, CallableContext, CallableId};
 pub use types::{Type, TypeStruct, TypingContext};
@@ -119,11 +120,8 @@ impl Context {
         match &expr.kind {
             typed_ir::ExprKind::Literal(lit) => Ok(lit.clone()),
             typed_ir::ExprKind::Path(_) => todo!("evaluate path"),
-            typed_ir::ExprKind::Call {
-                called,
-                args,
-                genargs,
-            } => todo!("evaluate call"),
+            typed_ir::ExprKind::Call(_call) => todo!("evaluate call"),
+            typed_ir::ExprKind::Match(_) => todo!(),
         }
     }
 
@@ -144,10 +142,10 @@ impl Context {
             }
             Expression::Literal(lit) => {
                 // TODO: make this a proper enum instead of having to match on everything
-                let data = match lit.kind() {
-                    parser::tokens::TokenKind::Number => {
-                        let num = lit.span().fragment().parse().unwrap();
-                        self.types.make_elabnum_u32(num)
+                let data = match lit.kind {
+                    parser::expression::LiteralKind::Num(num) => self.types.make_elabnum_u32(num),
+                    parser::expression::LiteralKind::Const(width, val) => {
+                        self.types.make_const_u32(width, val as u32)
                     }
                     _ => unreachable!("non-literal token in literal?"),
                 };
@@ -161,11 +159,11 @@ impl Context {
                 let a = self.type_expression(&op.a)?;
                 typed_ir::Expr {
                     id,
-                    kind: typed_ir::ExprKind::Call {
+                    kind: typed_ir::ExprKind::Call(typed_ir::Call {
                         called: self.callables.builtins.bitnot,
                         args: vec![a],
                         genargs: vec![],
-                    },
+                    }),
                     typ: self.types.primitives.infer,
                 }
             }
@@ -173,11 +171,11 @@ impl Context {
                 let (a, b) = (self.type_expression(&op.a)?, self.type_expression(&op.b)?);
                 typed_ir::Expr {
                     id,
-                    kind: typed_ir::ExprKind::Call {
+                    kind: typed_ir::ExprKind::Call(typed_ir::Call {
                         called: self.callables.builtins.xor,
                         args: vec![a, b],
                         genargs: vec![],
-                    },
+                    }),
                     typ: self.types.primitives.infer,
                 }
             }
@@ -202,14 +200,34 @@ impl Context {
                     .collect();
                 typed_ir::Expr {
                     id,
-                    kind: typed_ir::ExprKind::Call {
+                    kind: typed_ir::ExprKind::Call(typed_ir::Call {
                         called,
                         args: args_resolved,
                         genargs: genargs_resolved,
-                    },
+                    }),
                     typ: self.types.primitives.infer,
                 }
             }
+            Expression::BlockExpr(block) => match &**block {
+                BlockExpr::IfElse(_) => todo!(),
+                BlockExpr::Match(match_) => {
+                    let expr = self.type_expression(&match_.expr)?;
+                    let arms = match_
+                        .arms
+                        .iter()
+                        .map(|(cond, val)| {
+                            Ok((self.type_expression(cond)?, self.type_expression(val)?))
+                        })
+                        .collect::<Result<_, _>>()?;
+                    let typed = typed_ir::Match { expr, arms };
+                    typed_ir::Expr {
+                        id,
+                        kind: typed_ir::ExprKind::Match(Box::new(typed)),
+                        typ: self.types.primitives.infer,
+                    }
+                }
+                BlockExpr::Block(_) => todo!(),
+            },
         };
         Ok(t_expr)
     }
@@ -317,13 +335,13 @@ impl Context {
             typed_ir::ExprKind::Literal(lit) => expr.clone().with_type(lit.typ),
             // we can not see beyond this expression right now
             typed_ir::ExprKind::Path(_) => expr.clone(),
-            typed_ir::ExprKind::Call {
-                called,
-                args,
-                genargs,
-            } => {
-                let args_typed: Vec<_> = args.iter().map(|ex| self.infer_expr_types(ex)).collect();
-                let callee_def = self.callables.get(*called);
+            typed_ir::ExprKind::Call(call) => {
+                let args_typed: Vec<_> = call
+                    .args
+                    .iter()
+                    .map(|ex| self.infer_expr_types(ex))
+                    .collect();
+                let callee_def = self.callables.get(call.called);
 
                 let param_types: Vec<_> = callee_def.args.iter().map(|param| param.1).collect();
                 let inferred_args: Vec<_> = param_types
@@ -358,11 +376,27 @@ impl Context {
 
                 let mut new_expr = expr.clone();
                 new_expr.typ = new_type;
-                new_expr.kind = typed_ir::ExprKind::Call {
-                    called: called.clone(),
+                new_expr.kind = typed_ir::ExprKind::Call(typed_ir::Call {
+                    called: call.called.clone(),
                     args: args_typed,
                     genargs,
+                });
+                new_expr
+            }
+            typed_ir::ExprKind::Match(match_) => {
+                let new_arms: Vec<_> = match_
+                    .arms
+                    .iter()
+                    .map(|(pat, val)| (self.infer_expr_types(pat), self.infer_expr_types(val)))
+                    .collect();
+                // TODO: hacky hacky hacky
+                let res_type = new_arms.first().unwrap().1.typ;
+                let new_match = typed_ir::Match {
+                    expr: self.infer_expr_types(&match_.expr),
+                    arms: new_arms,
                 };
+                let mut new_expr = expr.clone().with_type(res_type);
+                new_expr.kind = typed_ir::ExprKind::Match(Box::new(new_match));
                 new_expr
             }
         }
@@ -429,20 +463,18 @@ impl Context {
                 lit_str
             }
             typed_ir::ExprKind::Path(path) => format!("sig_{}", path.0),
-            typed_ir::ExprKind::Call {
-                called,
-                args,
-                genargs,
-            } => {
-                let args = args
+            typed_ir::ExprKind::Call(call) => {
+                let args = call
+                    .args
                     .iter()
                     .map(|arg| {
                         self.pretty_typed_expr(w, arg)?;
                         Ok(format!("_{}", arg.id.0))
                     })
                     .collect::<Result<Vec<_>, std::fmt::Error>>()?;
-                let callable = self.callables.get(*called);
-                let genargs = genargs
+                let callable = self.callables.get(call.called);
+                let genargs = call
+                    .genargs
                     .iter()
                     .map(|param| {
                         let mut type_str = String::new();
@@ -457,6 +489,23 @@ impl Context {
                     args.join(", ")
                 )
             }
+            typed_ir::ExprKind::Match(match_) => {
+                self.pretty_typed_expr(w, &match_.expr)?;
+                let arms = match_
+                    .arms
+                    .iter()
+                    .map(|(pat, val)| {
+                        self.pretty_typed_expr(w, pat)?;
+                        self.pretty_typed_expr(w, val)?;
+                        Ok(format!("   _{} =>  _{}", pat.id.0, val.id.0))
+                    })
+                    .collect::<Result<Vec<_>, _>>()?;
+                format!(
+                    "match (_{}) {{\n{}\n}}",
+                    &match_.expr.id.0,
+                    arms.join(",\n")
+                )
+            }
         };
         let mut type_pretty = String::new();
         self.types.pretty_type(&mut type_pretty, expr.typ)?;
diff --git a/src/frontend/lowering.rs b/src/frontend/lowering.rs
index 9a9b787..8fb1a61 100644
--- a/src/frontend/lowering.rs
+++ b/src/frontend/lowering.rs
@@ -17,22 +17,19 @@ fn lower_expression(
     module.add_wire(expr_wire);
     match &expr.kind {
         ExprKind::Path(def) => Ok(rtlil::SigSpec::Wire(format!("\\$sig_{}", def.0))),
-        ExprKind::Call {
-            called,
-            args,
-            genargs,
-        } => {
-            let args_resolved = args
+        ExprKind::Call(call) => {
+            let args_resolved = call
+                .args
                 .iter()
                 .map(|expr| lower_expression(ctx, module, expr))
                 .collect::<Result<Vec<_>, _>>()?;
 
-            let callable = ctx.callables.get(*called);
+            let callable = ctx.callables.get(call.called);
             let cell_id = module.make_genid(callable.name());
 
-            if *called == ctx.callables.builtins.xor {
-                let a_width = ctx.types.get_width(args[0].typ).unwrap();
-                let b_width = ctx.types.get_width(args[1].typ).unwrap();
+            if call.called == ctx.callables.builtins.xor {
+                let a_width = ctx.types.get_width(call.args[0].typ).unwrap();
+                let b_width = ctx.types.get_width(call.args[1].typ).unwrap();
                 let y_width = ctx.types.get_width(expr.typ).unwrap();
                 let mut cell = rtlil::Cell::new(&cell_id, "$xor");
                 cell.add_param("\\A_SIGNED", "0");
@@ -44,8 +41,8 @@ fn lower_expression(
                 cell.add_connection("\\B", &args_resolved[1]);
                 cell.add_connection("\\Y", &rtlil::SigSpec::Wire(expr_wire_name.clone()));
                 module.add_cell(cell);
-            } else if *called == ctx.callables.builtins.reduce_or {
-                let a_width = ctx.types.get_width(args[0].typ).unwrap();
+            } else if call.called == ctx.callables.builtins.reduce_or {
+                let a_width = ctx.types.get_width(call.args[0].typ).unwrap();
                 let y_width = ctx.types.get_width(expr.typ).unwrap();
                 let mut cell = rtlil::Cell::new(&cell_id, "$reduce_or");
                 cell.add_param("\\A_SIGNED", "0");
@@ -54,8 +51,8 @@ fn lower_expression(
                 cell.add_connection("\\A", &args_resolved[0]);
                 cell.add_connection("\\Y", &rtlil::SigSpec::Wire(expr_wire_name.clone()));
                 module.add_cell(cell);
-            } else if *called == ctx.callables.builtins.bitnot {
-                let a_width = ctx.types.get_width(args[0].typ).unwrap();
+            } else if call.called == ctx.callables.builtins.bitnot {
+                let a_width = ctx.types.get_width(call.args[0].typ).unwrap();
                 let y_width = ctx.types.get_width(expr.typ).unwrap();
                 let mut cell = rtlil::Cell::new(&cell_id, "$not");
                 cell.add_param("\\A_SIGNED", "0");
@@ -72,6 +69,7 @@ fn lower_expression(
             todo!(),
             ctx.types.get_width(expr.typ).expect("signal has no size"),
         )),
+        ExprKind::Match(_) => todo!(),
     }
 }
 
diff --git a/src/frontend/typed_ir.rs b/src/frontend/typed_ir.rs
index e177d87..95d0f51 100644
--- a/src/frontend/typed_ir.rs
+++ b/src/frontend/typed_ir.rs
@@ -28,15 +28,25 @@ pub struct Expr {
     pub typ: Type,
 }
 
+#[derive(Debug, Clone)]
+pub struct Call {
+    pub called: CallableId,
+    pub args: Vec<Expr>,
+    pub genargs: Vec<Type>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Match {
+    pub expr: Expr,
+    pub arms: Vec<(Expr, Expr)>,
+}
+
 #[derive(Debug, Clone)]
 pub enum ExprKind {
     Literal(ElabData),
     Path(DefId),
-    Call {
-        called: CallableId,
-        args: Vec<Expr>,
-        genargs: Vec<Type>,
-    },
+    Call(Call),
+    Match(Box<Match>),
 }
 
 #[derive(Debug, Clone)]
diff --git a/src/frontend/types.rs b/src/frontend/types.rs
index 0948983..602c3de 100644
--- a/src/frontend/types.rs
+++ b/src/frontend/types.rs
@@ -1,3 +1,4 @@
+use std::cell::RefCell;
 use std::fmt::Debug;
 /// Alias for &TypeStruct to reduce repetition
 /// and make futura migration to interning
@@ -13,12 +14,12 @@ impl Debug for InternedType {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct TypeStruct {
     kind: TypeKind,
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 enum TypeKind {
     /// Elaboration-time types
     ElabType(ElabKind),
@@ -62,7 +63,7 @@ enum ElabValueData {
 }
 
 /// Types that are only valid during Elaboration
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 enum ElabKind {
     /// general, unsized number type
     Num,
@@ -95,7 +96,7 @@ pub struct PrimitiveTypes {
 }
 
 pub struct TypingContext {
-    types: Vec<TypeStruct>,
+    types: RefCell<Vec<TypeStruct>>,
     pub primitives: PrimitiveTypes,
 }
 
@@ -107,7 +108,7 @@ impl TypingContext {
             infer: InternedType(2),
         };
         Self {
-            types: vec![
+            types: RefCell::new(vec![
                 TypeStruct {
                     kind: TypeKind::ElabType(ElabKind::Num),
                 },
@@ -120,19 +121,19 @@ impl TypingContext {
                 TypeStruct {
                     kind: TypeKind::Infer,
                 },
-            ],
+            ]),
             primitives,
         }
     }
 
-    pub fn add(&mut self, typ: TypeStruct) -> Type {
-        let id = self.types.len();
-        self.types.push(typ);
+    pub fn add(&self, typ: TypeStruct) -> Type {
+        let id = self.types.borrow().len();
+        self.types.borrow_mut().push(typ);
         InternedType(id)
     }
 
-    pub fn get(&self, typ: Type) -> &TypeStruct {
-        &self.types[typ.0]
+    pub fn get(&self, typ: Type) -> TypeStruct {
+        self.types.borrow()[typ.0].clone()
     }
 
     pub fn make_elabnum_u32(&self, num: u32) -> ElabData {
@@ -142,7 +143,14 @@ impl TypingContext {
         }
     }
 
-    pub fn make_logic_size(&mut self, width: u32) -> Type {
+    pub fn make_const_u32(&self, width: u32, num: u32) -> ElabData {
+        ElabData {
+            typ: self.make_logic_size(width),
+            value: ElabValue::Concrete(ElabValueData::U32(num)),
+        }
+    }
+
+    pub fn make_logic_size(&self, width: u32) -> Type {
         let widthnum = self.make_elabnum_u32(width);
         self.parameterize(self.primitives.logic, &[GenericArg::Elab(widthnum)])
             .unwrap()
@@ -171,7 +179,7 @@ impl TypingContext {
         }
     }
 
-    pub fn parameterize(&mut self, typ: Type, params: &[GenericArg]) -> Option<Type> {
+    pub fn parameterize(&self, typ: Type, params: &[GenericArg]) -> Option<Type> {
         // TODO: return proper error type here
         match &self.get(typ).kind {
             // Elab types have no params yet
diff --git a/src/parser/block_expression.rs b/src/parser/block_expression.rs
new file mode 100644
index 0000000..cc3bc09
--- /dev/null
+++ b/src/parser/block_expression.rs
@@ -0,0 +1,57 @@
+use nom::{
+    branch::alt,
+    combinator::map,
+    error::context,
+    multi::{many1, separated_list1},
+    sequence::{delimited, separated_pair, tuple},
+};
+
+use crate::parser::{
+    assign_statement, expression,
+    expression::{expression, Expression},
+    tokens::{token, TokenKind as tk, TokenSpan},
+    Assign, IResult, Span,
+};
+
+#[derive(Debug, Clone)]
+pub enum BlockExpr<'a> {
+    IfElse(IfElseBlock),
+    Match(MatchBlock<'a>),
+    Block(Vec<BlockExpr<'a>>),
+}
+
+// TODO: postponed because annoying to implement
+#[derive(Debug, Clone)]
+pub struct IfElseBlock {}
+
+#[derive(Debug, Clone)]
+pub struct MatchBlock<'a> {
+    pub expr: Expression<'a>,
+    pub arms: Vec<(Expression<'a>, Expression<'a>)>,
+}
+
+fn match_arm(input: TokenSpan) -> IResult<TokenSpan, (Expression, Expression)> {
+    separated_pair(expression, token(tk::FatArrow), expression)(input)
+}
+
+fn match_block(input: TokenSpan) -> IResult<TokenSpan, MatchBlock> {
+    context(
+        "match block",
+        map(
+            tuple((
+                token(tk::Match),
+                delimited(token(tk::LParen), expression, token(tk::RParen)),
+                delimited(
+                    token(tk::LBrace),
+                    separated_list1(token(tk::Comma), match_arm),
+                    token(tk::RBrace),
+                ),
+            )),
+            |(_, expr, arms)| MatchBlock { expr, arms },
+        ),
+    )(input)
+}
+
+pub fn block_expr(input: TokenSpan) -> IResult<TokenSpan, BlockExpr> {
+    alt((map(match_block, BlockExpr::Match),))(input)
+}
diff --git a/src/parser/expression.rs b/src/parser/expression.rs
index 77d48b6..5408544 100644
--- a/src/parser/expression.rs
+++ b/src/parser/expression.rs
@@ -1,3 +1,5 @@
+use super::block_expression::{block_expr, BlockExpr};
+use super::literals;
 use super::tokens::{token, Token, TokenKind as tk, TokenSpan};
 use super::{IResult, Span};
 use nom::{
@@ -7,6 +9,18 @@ use nom::{
     sequence::{delimited, preceded, separated_pair, tuple},
 };
 
+#[derive(Debug, Clone)]
+pub struct Literal<'a> {
+    pub tok: Token<'a>,
+    pub kind: LiteralKind,
+}
+
+#[derive(Debug, Clone)]
+pub enum LiteralKind {
+    Num(u32),
+    Const(u32, u64),
+}
+
 #[derive(Debug, Clone)]
 pub struct Call<'a> {
     pub name: Span<'a>,
@@ -42,10 +56,11 @@ pub struct UnOp<'a> {
 #[derive(Debug, Clone)]
 pub enum Expression<'a> {
     Path(&'a str),
-    Literal(Token<'a>),
+    Literal(Literal<'a>),
     UnOp(Box<UnOp<'a>>),
     BinOp(Box<BinOp<'a>>),
     Call(Box<Call<'a>>),
+    BlockExpr(Box<BlockExpr<'a>>),
 }
 
 /// expressions that can't be subdivided further
@@ -55,7 +70,19 @@ fn atom(input: TokenSpan) -> IResult<TokenSpan, Expression> {
         map(token(tk::Ident), |it| {
             Expression::Path(it.span().fragment())
         }),
-        map(token(tk::Number), Expression::Literal),
+        map(token(tk::Number), |tok| {
+            Expression::Literal(Literal {
+                tok,
+                kind: LiteralKind::Num(tok.span().parse().expect("invalid literal")),
+            })
+        }),
+        map(token(tk::Constant), |tok| {
+            let (_, (width, val)) = literals::const_bits(tok.span()).expect("invalid literal");
+            Expression::Literal(Literal {
+                tok,
+                kind: LiteralKind::Const(width, val),
+            })
+        }),
         delimited(token(tk::LParen), expression, token(tk::RParen)),
     ))(input)
 }
@@ -119,11 +146,11 @@ pub fn call_item(input: TokenSpan) -> IResult<TokenSpan, Call> {
     )(input)
 }
 
-/// parser combinators can not parse left-recursive grammars. To work around this, we split
-/// expressions into a recursive and non-recursive portion.
-/// Parsers reachable from this point must call expression_nonrecurse instead
 pub fn expression(input: TokenSpan) -> IResult<TokenSpan, Expression> {
-    bitop(input)
+    alt((
+        bitop,
+        map(block_expr, |blk| Expression::BlockExpr(Box::new(blk))),
+    ))(input)
 }
 
 #[cfg(test)]
diff --git a/src/parser/literals.rs b/src/parser/literals.rs
index 13301a4..89273b2 100644
--- a/src/parser/literals.rs
+++ b/src/parser/literals.rs
@@ -1,15 +1,27 @@
 use nom::{
     branch::alt,
     bytes::complete::tag,
-    character::complete::{alpha1, alphanumeric1, char, multispace0, one_of},
+    character::complete::{alpha1, alphanumeric1, char, digit1, multispace0, one_of},
     combinator::{map, recognize},
     error::ParseError,
     multi::{many0, many1},
-    sequence::{delimited, pair, preceded, terminated},
+    sequence::{delimited, pair, preceded, separated_pair, terminated},
 };
 
 use crate::parser::{IResult, Span};
 
+pub fn const_bits(input: Span) -> IResult<Span, (u32, u64)> {
+    map(
+        separated_pair(digit1, char('\''), digit1),
+        |(width, value): (Span, Span)| {
+            (
+                width.fragment().parse().expect("error parsing literal"),
+                value.fragment().parse().expect("error parsing literal"),
+            )
+        },
+    )(input)
+}
+
 pub fn hexadecimal(input: Span) -> IResult<Span, u64> {
     map(
         preceded(
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index d1ece5f..f154915 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -1,4 +1,5 @@
 pub mod adt;
+pub mod block_expression;
 pub mod comb;
 pub mod declaration;
 pub mod error;
diff --git a/src/parser/proc.rs b/src/parser/proc.rs
index 1008f09..7bfc1e1 100644
--- a/src/parser/proc.rs
+++ b/src/parser/proc.rs
@@ -3,12 +3,11 @@ use nom::{
     combinator::map,
     error::context,
     multi::{many1, separated_list1},
-    sequence::{delimited, separated_pair, tuple},
+    sequence::{delimited, tuple},
 };
 
 use crate::parser::{
-    assign_statement, expression,
-    expression::{expression, Expression},
+    assign_statement,
     tokens::{token, TokenKind as tk, TokenSpan},
     Assign, IResult, Span,
 };
@@ -21,42 +20,7 @@ pub struct ProcBlock<'a> {
 
 #[derive(Debug)]
 pub enum ProcStatement<'a> {
-    IfElse(IfElseBlock),
     Assign(Assign<'a>),
-    Match(MatchBlock<'a>),
-    Block(Vec<ProcStatement<'a>>),
-}
-
-// TODO: postponed because annoying to implement
-#[derive(Debug)]
-pub struct IfElseBlock {}
-
-#[derive(Debug)]
-pub struct MatchBlock<'a> {
-    pub expr: Expression<'a>,
-    pub arms: Vec<(Expression<'a>, ProcStatement<'a>)>,
-}
-
-fn match_arm(input: TokenSpan) -> IResult<TokenSpan, (Expression, ProcStatement)> {
-    separated_pair(expression, token(tk::FatArrow), proc_statement)(input)
-}
-
-fn match_block(input: TokenSpan) -> IResult<TokenSpan, MatchBlock> {
-    context(
-        "match block",
-        map(
-            tuple((
-                token(tk::Match),
-                delimited(token(tk::LParen), expression, token(tk::RParen)),
-                delimited(
-                    token(tk::LBrace),
-                    separated_list1(token(tk::Comma), match_arm),
-                    token(tk::RBrace),
-                ),
-            )),
-            |(_, expr, arms)| MatchBlock { expr, arms },
-        ),
-    )(input)
 }
 
 fn statement_block(input: TokenSpan) -> IResult<TokenSpan, Vec<ProcStatement>> {
@@ -69,11 +33,7 @@ fn statement_block(input: TokenSpan) -> IResult<TokenSpan, Vec<ProcStatement>> {
 
 /// parse a statement that is valid inside a proc block
 fn proc_statement(input: TokenSpan) -> IResult<TokenSpan, ProcStatement> {
-    alt((
-        map(match_block, ProcStatement::Match),
-        map(statement_block, ProcStatement::Block),
-        map(assign_statement, ProcStatement::Assign),
-    ))(input)
+    alt((map(assign_statement, ProcStatement::Assign),))(input)
 }
 
 pub fn proc_block(input: TokenSpan) -> IResult<TokenSpan, ProcBlock> {
diff --git a/src/parser/tokens.rs b/src/parser/tokens.rs
index 59734c1..ecf048d 100644
--- a/src/parser/tokens.rs
+++ b/src/parser/tokens.rs
@@ -2,7 +2,7 @@
 
 use super::{
     error::{Error, InputPos},
-    literals::{identifier, ws0},
+    literals::{const_bits, identifier, ws0},
     IResult, Span,
 };
 use nom::{
@@ -77,6 +77,7 @@ pub enum TokenKind {
     // Literals
     Ident,
     Number,
+    Constant,
     // Keywords
     Module,
     Assign,
@@ -186,6 +187,7 @@ fn lex_braces(input: Span) -> IResult<Span, Token> {
 fn lex_literals(input: Span) -> IResult<Span, Token> {
     map(
         consumed(alt((
+            map(const_bits, |_| TokenKind::Constant),
             map(identifier, |_| TokenKind::Ident),
             map(digit1, |_| TokenKind::Number),
         ))),