Teach the compiler to handle syntax objects as input

src/common.cpp

@@ -527,7 +527,9 @@ Result<Dict> Dict::create(const Array& arr) {
 
 Result<Value> Dict::get(const Value& key) const {
   auto pos = TRY(find(key));
-  if (pos >= size()) return ERROR(KeyError);
+  if (pos >= size()) {
+    return ERROR(KeyError);
+  }
   auto k = TRY(Value::create(_value->data[pos * 2].get()));
 
   if (TRY(k.cmp(key)) != 0) {
@@ -751,3 +753,51 @@ Result<Value> Object::second() const { return ERROR(TypeMismatch); }
 Result<Value> Object::third() const { return ERROR(TypeMismatch); }
 
 Result<Value> Object::rest() const { return ERROR(TypeMismatch); }
+
+Result<bool> syntax_is_list(const Value& value) {
+  if (!value.is<Syntax>()) return value.is<Pair>();
+
+  auto val = TRY(value.to<Syntax>()->expression());
+  return val.is<Pair>();
+}
+
+Result<bool> syntax_is_nil(const Value& value) {
+  if (!value.is<Syntax>()) return value.is<Nil>();
+
+  auto val = TRY(value.to<Syntax>()->expression());
+  return val.is<Nil>();
+}
+
+Result<Value> syntax_first(const Value& value) {
+  if (!value.is<Syntax>()) return value.first();
+
+  auto val = TRY(value.to<Syntax>()->expression());
+  return val.first();
+}
+
+Result<Value> syntax_second(const Value& value) {
+  if (!value.is<Syntax>()) return value.second();
+
+  auto val = TRY(value.to<Syntax>()->expression());
+  return val.second();
+}
+
+Result<Value> syntax_third(const Value& value) {
+  if (!value.is<Syntax>()) return value.third();
+
+  auto val = TRY(value.to<Syntax>()->expression());
+  return val.third();
+}
+
+Result<Value> syntax_rest(const Value& value) {
+  if (!value.is<Syntax>()) return value.rest();
+
+  auto val = TRY(value.to<Syntax>()->expression());
+  return val.rest();
+}
+
+Result<Value> syntax_unwrap(const Value& value) {
+  if (!value.is<Syntax>()) return value.copy();
+
+  return TRY(value.to<Syntax>()->expression());
+}

src/common.hpp

@@ -1243,3 +1243,11 @@ Result<Array> Array::append(const V& value) const {
   Value v = TRY(Value::create(value));
   return append(v);
 }
+
+Result<bool> syntax_is_list(const Value& value);
+Result<bool> syntax_is_nil(const Value& value);
+Result<Value> syntax_first(const Value& value);
+Result<Value> syntax_second(const Value& value);
+Result<Value> syntax_third(const Value& value);
+Result<Value> syntax_rest(const Value& value);
+Result<Value> syntax_unwrap(const Value& value);

src/compiler.cpp

@@ -192,7 +192,7 @@ Result<Value> Compiler::compile(Value& expr) {
   }
 
   // Otherwise perform actual compilation of the expression
-  if (!expr.is<Pair>()) {
+  if (!TRY(syntax_is_list(expr))) {
     return ERROR(CompilationError);
   }
 
@@ -212,7 +212,8 @@ Result<Value> Compiler::compile(Value& expr) {
 }
 
 Result<Expression> Compiler::compile_expr(Context& context, const Value& expr) {
-  switch (expr.tag()) {
+  auto unwrapped = TRY(syntax_unwrap(expr));
+  switch (unwrapped.tag()) {
     case Tag::Pair:
       return compile_list(context, expr);
     case Tag::Int64:
@@ -244,7 +245,7 @@ Result<Expression> Compiler::compile_expr(Context& context, const Value& expr) {
 
 Result<Expression> Compiler::compile_primop(Context& context, Symbol& op,
                                             const Value& expr) {
-  Value cur = TRY(expr.rest());
+  Value cur = TRY(syntax_rest(expr));
   Expression ex = TRY(Expression::create());
 
   Oc opcode = Oc::Unknown;
@@ -269,7 +270,7 @@ Result<Expression> Compiler::compile_primop(Context& context, Symbol& op,
     return ex;
   }
 
-  auto subexpr = TRY(cur.first());
+  auto subexpr = TRY(syntax_first(cur));
 
   auto comp = TRY(compile_expr(context, subexpr));
 
@@ -277,16 +278,16 @@ Result<Expression> Compiler::compile_primop(Context& context, Symbol& op,
   uint64_t firstreg = comp.reg;
   uint64_t reg = firstreg;
 
-  cur = TRY(cur.rest());
+  cur = TRY(syntax_rest(cur));
 
   while (!cur.is<Nil>()) {
-    auto subexpr = TRY(cur.first());
+    auto subexpr = TRY(syntax_first(cur));
 
     auto comp = TRY(compile_expr(context, subexpr));
 
     ex.add_code(comp.code);
 
-    auto rest = TRY(cur.rest());
+    auto rest = TRY(syntax_rest(cur));
 
     uint64_t res = 0;
     if (rest.is<Nil>())
@@ -308,7 +309,7 @@ Result<Expression> Compiler::compile_primop(Context& context, Symbol& op,
 
 Result<Expression> Compiler::compile_comparison(Context& context, Symbol& op,
                                                 const Value& expr) {
-  Value cur = TRY(expr.rest());
+  Value cur = TRY(syntax_rest(expr));
   Expression ex = TRY(Expression::create());
 
   Oc opcode = Oc::Unknown;
@@ -345,7 +346,7 @@ Result<Expression> Compiler::compile_comparison(Context& context, Symbol& op,
   int64_t false_c = TRY(context.add_const(TRY(Bool::create(false))));
   TRY(ex.add_opcode(Oc::Mov, {0, (int64_t)result}, {1, true_c}));
 
-  auto subexpr = TRY(cur.first());
+  auto subexpr = TRY(syntax_first(cur));
 
   auto comp = TRY(compile_expr(context, subexpr));
 
@@ -353,16 +354,16 @@ Result<Expression> Compiler::compile_comparison(Context& context, Symbol& op,
   uint64_t firstreg = comp.reg;
   uint64_t reg = firstreg;
 
-  cur = TRY(cur.rest());
+  cur = TRY(syntax_rest(cur));
 
   while (!cur.is<Nil>()) {
-    auto subexpr = TRY(cur.first());
+    auto subexpr = TRY(syntax_first(cur));
 
     auto comp = TRY(compile_expr(context, subexpr));
 
     ex.add_code(comp.code);
 
-    auto rest = TRY(cur.rest());
+    auto rest = TRY(syntax_rest(cur));
 
     TRY(ex.add_opcode(opcode, {0, (int64_t)reg}, {0, (int64_t)comp.reg},
                       {0, (int64_t)cmp_expected}));
@@ -380,25 +381,25 @@ Result<Expression> Compiler::compile_comparison(Context& context, Symbol& op,
 
 Result<Expression> Compiler::compile_if(Context& context, Symbol& op,
                                         const Value& expr) {
-  Value first = TRY(expr.rest());
+  Value first = TRY(syntax_rest(expr));
   Expression ex = TRY(Expression::create());
-  if (!first.is<Pair>()) {
+  if (!TRY(syntax_is_list(first))) {
     return ERROR(CompilationError);
   }
 
-  Value second = TRY(first.rest());
+  Value second = TRY(syntax_rest(first));
 
-  if (!second.is<Pair>()) {
+  if (!TRY(syntax_is_list(second))) {
     return ERROR(CompilationError);
   }
 
-  Value third = TRY(second.rest());
+  Value third = TRY(syntax_rest(second));
 
-  if (!third.is<Pair>()) {
+  if (!TRY(syntax_is_list(third))) {
     return ERROR(CompilationError);
   }
 
-  auto condition = TRY(first.first());
+  auto condition = TRY(syntax_first(first));
 
   auto condition_comp = TRY(compile_expr(context, condition));
 
@@ -406,14 +407,14 @@ Result<Expression> Compiler::compile_if(Context& context, Symbol& op,
   uint64_t firstreg = condition_comp.reg;
   uint64_t reg = firstreg;
 
-  auto option1 = TRY(second.first());
+  auto option1 = TRY(syntax_first(second));
   auto option1_comp = TRY(compile_expr(context, option1));
 
   uint64_t option1_reg = option1_comp.reg;
 
   context.maxreg = firstreg + 1;
 
-  auto option2 = TRY(third.first());
+  auto option2 = TRY(syntax_first(third));
   auto option2_comp = TRY(compile_expr(context, option2));
 
   int64_t true_const = TRY(context.add_const(TRY(Bool::create(true))));
@@ -439,9 +440,9 @@ Result<Expression> Compiler::compile_if(Context& context, Symbol& op,
 
 Result<Expression> Compiler::compile_and(Context& context, Symbol& op,
                                          const Value& expr) {
-  Value param = TRY(expr.rest());
+  Value param = TRY(syntax_rest(expr));
   Expression ex = TRY(Expression::create());
-  if (param.is<Nil>() || !param.is<Pair>()) {
+  if (!TRY(syntax_is_list(param))) {
     return ERROR(CompilationError);
   }
 
@@ -454,12 +455,12 @@ Result<Expression> Compiler::compile_and(Context& context, Symbol& op,
   bool is_first = true;
 
   while (!param.is<Nil>()) {
-    if (!param.is<Pair>()) {
+    if (!TRY(syntax_is_list(param))) {
       return ERROR(CompilationError);
     }
 
-    auto rest = TRY(param.rest());
+    auto rest = TRY(syntax_rest(param));
-    Value param_val = TRY(param.first());
+    Value param_val = TRY(syntax_first(param));
 
     auto param_ex = TRY(compile_expr(context, param_val));
 
@@ -486,9 +487,9 @@ Result<Expression> Compiler::compile_and(Context& context, Symbol& op,
 
 Result<Expression> Compiler::compile_or(Context& context, Symbol& op,
                                         const Value& expr) {
-  Value param = TRY(expr.rest());
+  Value param = TRY(syntax_rest(expr));
   Expression ex = TRY(Expression::create());
-  if (param.is<Nil>() || !param.is<Pair>()) {
+  if (!TRY(syntax_is_list(param))) {
     return ERROR(CompilationError);
   }
 
@@ -501,12 +502,12 @@ Result<Expression> Compiler::compile_or(Context& context, Symbol& op,
   bool is_first = true;
 
   while (!param.is<Nil>()) {
-    if (!param.is<Pair>()) {
+    if (!TRY(syntax_is_list(param))) {
       return ERROR(CompilationError);
     }
 
-    auto rest = TRY(param.rest());
+    auto rest = TRY(syntax_rest(param));
-    Value param_val = TRY(param.first());
+    Value param_val = TRY(syntax_first(param));
 
     auto param_ex = TRY(compile_expr(context, param_val));
 
@@ -533,13 +534,13 @@ Result<Expression> Compiler::compile_or(Context& context, Symbol& op,
 
 Result<Expression> Compiler::compile_not(Context& context, Symbol& op,
                                          const Value& expr) {
-  Value first = TRY(expr.rest());
+  Value first = TRY(syntax_rest(expr));
   Expression ex = TRY(Expression::create());
-  if (first.is<Nil>() || !first.is<Pair>()) {
+  if (!TRY(syntax_is_list(first))) {
     return ERROR(CompilationError);
   }
 
-  auto first_expr = TRY(first.first());
+  auto first_expr = TRY(syntax_first(first));
 
   uint64_t result = context.alloc_reg();
   int64_t true_c = TRY(context.add_const(TRY(Bool::create(true))));
@@ -560,10 +561,11 @@ Result<Expression> Compiler::compile_not(Context& context, Symbol& op,
 
 Result<Expression> Compiler::compile_def(Context& context, Symbol& op,
                                          const Value& expr) {
-  auto varname = TRY(expr.second());
+  auto varname = TRY(syntax_second(expr));
-  if (!varname.is<Symbol>()) return ERROR(CompilationError);
+  auto varname_unwrapped = TRY(syntax_unwrap(varname));
+  if (!varname_unwrapped.is<Symbol>()) return ERROR(CompilationError);
 
-  auto var_expr = TRY(expr.third());
+  auto var_expr = TRY(syntax_third(expr));
 
   uint64_t maxreg = context.maxreg;
   Expression ex = TRY(Expression::create());
@@ -571,7 +573,7 @@ Result<Expression> Compiler::compile_def(Context& context, Symbol& op,
   auto comp = TRY(compile_expr(context, var_expr));
   ex.add_code(comp.code);
 
-  int64_t gname = TRY(context.add_const(varname));
+  int64_t gname = TRY(context.add_const(varname_unwrapped));
   TRY(ex.add_opcode(Oc::GlobalStore, {1, (int64_t)gname},
                     {0, (int64_t)comp.reg}));
 
@@ -586,49 +588,51 @@ Result<Expression> Compiler::compile_fn(Context& context, Symbol& op,
   Context ctx = TRY(Context::create(context));
   ctx.maxreg = 1;  // Reserve the slot for function itself
 
-  auto first = TRY(expr.rest());
+  auto first = TRY(syntax_rest(expr));
 
-  if (!first.is<Pair>()) {
+  if (!TRY(syntax_is_list(first))) {
     return ERROR(CompilationError);
   }
 
   Value name = TRY(Nil::create());
 
-  auto maybe_name = TRY(first.first());
+  auto maybe_name = TRY(syntax_first(first));
+  auto maybe_name_unwrapped = TRY(syntax_unwrap(maybe_name));
 
-  if (maybe_name.is<Symbol>()) {
+  if (maybe_name_unwrapped.is<Symbol>()) {
-    name = TRY(maybe_name.copy());
+    name = TRY(maybe_name_unwrapped.copy());
     ctx.fname = TRY(name.copy());
 
-    first = TRY(first.rest());
+    first = TRY(syntax_rest(first));
 
-    if (first.is<Nil>() || !first.is<Pair>()) {
+    if (!TRY(syntax_is_list(first))) {
       return ERROR(CompilationError);
     }
   }
 
-  auto param = TRY(first.first());
+  auto param = TRY(syntax_first(first));
 
   uint64_t arity = 0;
-  while (!param.is<Nil>()) {
+  while (!TRY(syntax_is_nil(param))) {
-    if (!param.is<Pair>()) {
+    if (!TRY(syntax_is_list(param))) {
       return ERROR(CompilationError);
     }
-    auto param_name = TRY(param.first());
+    auto param_name = TRY(syntax_first(param));
+    auto param_name_unwrapped = TRY(syntax_unwrap(param_name));
 
-    if (!param_name.is<Symbol>()) {
+    if (!param_name_unwrapped.is<Symbol>()) {
       return ERROR(CompilationError);
     }
 
-    int64_t reg = TRY(ctx.add_var(param_name));
+    int64_t reg = TRY(ctx.add_var(param_name_unwrapped));
 
-    param = TRY(param.rest());
+    param = TRY(syntax_rest(param));
     arity++;
   }
 
-  Value second = TRY(first.rest());
+  Value second = TRY(syntax_rest(first));
 
-  if (second.is<Nil>() || !second.is<Pair>()) {
+  if (!TRY(syntax_is_list(second))) {
     return ERROR(CompilationError);
   }
 
@@ -720,43 +724,44 @@ Result<Expression> Compiler::compile_let(Context& context, Symbol& op,
   // Save the variable bindings to restore it later
   Dict saved_vars = TRY(context.variables_dict.copy());
 
-  auto first = TRY(expr.rest());
+  auto first = TRY(syntax_rest(expr));
 
-  if (first.is<Nil>() || !first.is<Pair>()) {
+  if (!TRY(syntax_is_list(first))) {
     return ERROR(CompilationError);
   }
 
   uint64_t maxreg = context.maxreg;
 
-  auto bindings = TRY(first.first());
+  auto bindings = TRY(syntax_first(first));
 
   Expression ex_res = TRY(Expression::create());
 
   while (!bindings.is<Nil>()) {
-    auto binding = TRY(bindings.first());
+    auto binding = TRY(syntax_first(bindings));
 
-    if (!binding.is<Pair>()) {
+    if (!TRY(syntax_is_list(binding))) {
       return ERROR(CompilationError);
     }
 
-    auto binding_name = TRY(binding.first());
+    auto binding_name = TRY(syntax_first(binding));
-    auto binding_expr = TRY(binding.second());
+    auto binding_name_unwrapped = TRY(syntax_unwrap(binding_name));
+    auto binding_expr = TRY(syntax_second(binding));
 
-    if (!binding_name.is<Symbol>()) return ERROR(CompilationError);
+    if (!binding_name_unwrapped.is<Symbol>()) return ERROR(CompilationError);
 
-    int64_t reg = TRY(context.update_var(binding_name));
+    int64_t reg = TRY(context.update_var(binding_name_unwrapped));
     auto ex = TRY(compile_expr(context, binding_expr));
     TRY(ex.add_opcode(Oc::Mov, {0, (int64_t)reg}, {0, (int64_t)ex.reg}));
     context.maxreg = reg + 1;
 
     ex_res.add_code(ex.code);
 
-    bindings = TRY(bindings.rest());
+    bindings = TRY(syntax_rest(bindings));
   }
 
-  Value second = TRY(first.rest());
+  Value second = TRY(syntax_rest(first));
 
-  if (!second.is<Pair>()) {
+  if (!TRY(syntax_is_list(second))) {
     return ERROR(CompilationError);
   }
 
@@ -780,10 +785,10 @@ Result<Expression> Compiler::compile_body(Context& context, const Value& expr) {
   int64_t maxreg = context.maxreg;
 
   while (!cur.is<Nil>()) {
-    if (!cur.is<Pair>()) {
+    if (!TRY(syntax_is_list(cur))) {
       return ERROR(CompilationError);
     }
-    auto expr_val = TRY(cur.first());
+    auto expr_val = TRY(syntax_first(cur));
 
     // debug_print(expr_val);
 
@@ -791,7 +796,7 @@ Result<Expression> Compiler::compile_body(Context& context, const Value& expr) {
 
     TRY(ex_res.add_code(expr.code));
 
-    cur = TRY(cur.rest());
+    cur = TRY(syntax_rest(cur));
 
     if (cur.is<Nil>()) {
       ex_res.reg = expr.reg;
@@ -807,12 +812,14 @@ Result<Expression> Compiler::compile_function_call(Context& context,
                                                    const Value& expr) {
   auto ex = TRY(Expression::create());
 
-  auto first = TRY(expr.first());
+  auto first = TRY(syntax_first(expr));
-  auto param = TRY(expr.rest());
+  auto first_unwrapped = TRY(syntax_unwrap(first));
+  auto param = TRY(syntax_rest(expr));
 
   bool is_self_call = false;
   uint64_t firstreg = context.maxreg;
-  if (first.is<Symbol>() && TRY(first.cmp(context.fname)) == 0) {
+  if (first_unwrapped.is<Symbol>() &&
+      TRY(first_unwrapped.cmp(context.fname)) == 0) {
     int64_t r = context.alloc_reg();
     int64_t c = TRY(context.add_const(TRY(Nil::create())));
     TRY(ex.add_opcode(Oc::Mov, {0, (int64_t)r}, {1, (int64_t)c}));
@@ -824,15 +831,15 @@ Result<Expression> Compiler::compile_function_call(Context& context,
 
   int64_t maxreg = context.maxreg;
   while (!param.is<Nil>()) {
-    if (!param.is<Pair>()) {
+    if (!TRY(syntax_is_list(param))) {
       return ERROR(CompilationError);
     }
-    Value param_val = TRY(param.first());
+    Value param_val = TRY(syntax_first(param));
 
     auto param_ex = TRY(compile_expr(context, param_val));
     TRY(ex.add_code(param_ex.code));
 
-    param = TRY(param.rest());
+    param = TRY(syntax_rest(param));
   }
 
   if (is_self_call) {
@@ -849,10 +856,11 @@ Result<Expression> Compiler::compile_function_call(Context& context,
 }
 
 Result<Expression> Compiler::compile_list(Context& context, const Value& expr) {
-  auto first = TRY(expr.first());
+  auto first = TRY(syntax_first(expr));
+  auto unwrapped = TRY(syntax_unwrap(first));
 
-  if (first.is<Symbol>()) {
+  if (unwrapped.is<Symbol>()) {
-    Symbol& sym = *first.to<Symbol>();
+    Symbol& sym = *unwrapped.to<Symbol>();
     if (TRY(is_primitive_op(sym))) {
       return compile_primop(context, sym, expr);
     } else if (TRY(is_comparison_op(sym))) {
@@ -874,7 +882,7 @@ Result<Expression> Compiler::compile_list(Context& context, const Value& expr) {
     } else {
       return compile_function_call(context, expr);
     }
-  } else if (first.is<Pair>()) {
+  } else if (TRY(syntax_is_list(first))) {
     return compile_function_call(context, expr);
   }
 
@@ -886,7 +894,8 @@ Result<Expression> Compiler::compile_constant(Context& context,
   Expression ex = TRY(Expression::create());
   uint64_t reg = context.alloc_reg();
 
-  int64_t c = TRY(context.add_const(value));
+  auto unwrapped = TRY(syntax_unwrap(value));
+  int64_t c = TRY(context.add_const(unwrapped));
 
   TRY(ex.add_opcode(Oc::Mov, {0, (int64_t)reg}, {1, (int64_t)c}));
 
@@ -898,14 +907,16 @@ Result<Expression> Compiler::compile_symbol(Context& context,
                                             const Value& value) {
   Expression ex = TRY(Expression::create());
 
+  auto unwrapped = TRY(syntax_unwrap(value));
+
   // Symbol may be self-evaluating (e.g. :foo), in which case we just use it as
   // its own value
 
-  if (value.is<Symbol>()) {
+  if (unwrapped.is<Symbol>()) {
-    Symbol& sym = *value.to<Symbol>();
+    Symbol& sym = *unwrapped.to<Symbol>();
 
     if (sym.size() > 0 && TRY(sym[0]) == ':') {
-      int64_t c = TRY(context.add_const(value));
+      int64_t c = TRY(context.add_const(unwrapped));
 
       uint64_t reg = context.alloc_reg();
       TRY(ex.add_opcode(Oc::Mov, {0, (int64_t)reg}, {1, (int64_t)c}));
@@ -915,7 +926,7 @@ Result<Expression> Compiler::compile_symbol(Context& context,
     }
   }
 
-  auto maybe_reg = context.get_var(TRY(value.copy()));
+  auto maybe_reg = context.get_var(TRY(unwrapped.copy()));
 
   if (!maybe_reg.has_error()) {
     auto var_reg = maybe_reg.value();
@@ -927,7 +938,8 @@ Result<Expression> Compiler::compile_symbol(Context& context,
     return std::move(ex);
   }
 
-  auto maybe_stdlib_fun = get_stdlib_function(*value.to<Symbol>());
+  if (unwrapped.is<Symbol>()) {
+    auto maybe_stdlib_fun = get_stdlib_function(*unwrapped.to<Symbol>());
 
     if (!maybe_stdlib_fun.has_error()) {
       auto stdlib_fun = TRY(StdlibFunction::create(maybe_stdlib_fun.value()));
@@ -939,11 +951,12 @@ Result<Expression> Compiler::compile_symbol(Context& context,
       ex.reg = reg;
       return std::move(ex);
     }
+  }
 
   // Most variable references in function bodies will fall back to loading the
   // accessed variables from parent closures.
   if (!context.toplevel) {
-    auto maybe_closure = context.get_closure(TRY(value.copy()));
+    auto maybe_closure = context.get_closure(TRY(unwrapped.copy()));
 
     if (!maybe_closure.has_error()) {
       auto var_closure = maybe_closure.value();
@@ -960,7 +973,7 @@ Result<Expression> Compiler::compile_symbol(Context& context,
   // Otherwise treat unknown symbol as a global and try to load it from the
   // global scope. This usually happens in toplevel expressions.
 
-  int64_t c = TRY(context.add_const(TRY(value.copy())));
+  int64_t c = TRY(context.add_const(TRY(unwrapped.copy())));
 
   uint64_t reg = context.alloc_reg();
   TRY(ex.add_opcode(Oc::GlobalLoad, {0, (int64_t)reg}, {1, (int64_t)c}));

src/valeri.cpp

@@ -13,7 +13,7 @@
 StaticArena<64 * 1024 * 1024> arena;
 
 Result<Value> run_string(const String& src) {
-  auto parsed = TRY(read_multiple(src, false));
+  auto parsed = TRY(read_multiple(src));
 
   TRY(arena_gc());
 
@@ -32,7 +32,7 @@ Result<void> run_repl() {
 
   while (true) {
     auto src = TRY(read_line("valeri> "));
-    auto parsed = TRY(read_multiple(src, false));
+    auto parsed = TRY(read_multiple(src));
     auto compiled = TRY(compile(parsed));
     Module& mod = *compiled.to<Module>();
     auto vm = TRY(VM::create());

src/writer.cpp

@@ -1,5 +1,6 @@
 #include "writer.hpp"
 
+#include "common.hpp"
 #include "error.hpp"
 #include "opcode.hpp"
 #include "sourcerange.hpp"
@@ -196,7 +197,15 @@ Result<String> Writer::write_srcloc(const SrcLoc& val) {
 }
 
 Result<String> Writer::write_syntax(const Syntax& val) {
-  return TRY(String::create("#<syntax>"));
+  auto res = TRY(String::create("#<syntax "));
+
+  auto unwrapped = TRY(syntax_unwrap(TRY(val.copy_value())));
+  auto str = TRY(write_one(unwrapped));
+
+  res = TRY(res.concat(str));
+
+  res = TRY(res.concat(">"));
+  return res;
 }
 
 Result<String> Writer::write_pair(const Pair& val) {