diff --git a/bin/compiler.js b/bin/compiler.js
index 5fc68f2..0114e69 100644
--- a/bin/compiler.js
+++ b/bin/compiler.js
@@ -27,7 +27,7 @@ var special63 = function (k) {
   return is63(getenv(k, "special"));
 };
 var special_form63 = function (form) {
-  return ! atom63(form) && special63(hd(form));
+  return hd63(form, special63);
 };
 var statement63 = function (k) {
   return special63(k) && getenv(k, "stmt");
@@ -197,7 +197,7 @@ var can_unquote63 = function (depth) {
   return quoting63(depth) && depth === 1;
 };
 var quasisplice63 = function (x, depth) {
-  return can_unquote63(depth) && ! atom63(x) && hd(x) === "unquote-splicing";
+  return can_unquote63(depth) && hd63(x, "unquote-splicing");
 };
 var expand_local = function (__x38) {
   var ____id1 = __x38;
@@ -576,7 +576,7 @@ var infix63 = function (x) {
   return is63(getop(x));
 };
 infix_operator63 = function (x) {
-  return obj63(x) && infix63(hd(x));
+  return hd63(x, infix63);
 };
 var compile_args = function (args) {
   var __s1 = "(";
@@ -683,7 +683,7 @@ var compile_special = function (form, stmt63) {
   return apply(__special, __args2) + __tr;
 };
 var parenthesize_call63 = function (x) {
-  return ! atom63(x) && hd(x) === "%function" || precedence(x) > 0;
+  return hd63(x, "%function") || precedence(x) > 0;
 };
 var compile_call = function (form) {
   var __f = hd(form);
@@ -811,7 +811,7 @@ compile = function (form) {
         __e45 = compile_atom(__form);
       } else {
         var __e46 = undefined;
-        if (infix63(hd(__form))) {
+        if (infix_operator63(__form)) {
           __e46 = compile_infix(__form);
         } else {
           __e46 = compile_call(__form);
@@ -853,7 +853,7 @@ var literal63 = function (form) {
   return atom63(form) || hd(form) === "%array" || hd(form) === "%object";
 };
 var standalone63 = function (form) {
-  return ! atom63(form) && ! infix63(hd(form)) && ! literal63(form) && !( "get" === hd(form)) || id_literal63(form);
+  return ! atom63(form) && ! infix_operator63(form) && ! literal63(form) && ! hd63(form, "get") || id_literal63(form);
 };
 var lower_do = function (args, hoist, stmt63, tail63) {
   var ____x95 = almost(args);
@@ -992,7 +992,7 @@ var lower_pairwise = function (form) {
   }
 };
 var lower_infix63 = function (form) {
-  return infix63(hd(form)) && _35(form) > 3;
+  return infix_operator63(form) && _35(form) > 3;
 };
 var lower_infix = function (form, hoist) {
   var __form3 = lower_pairwise(form);
@@ -1090,7 +1090,9 @@ _eval = function (form) {
   return _37result;
 };
 immediate_call63 = function (x) {
-  return obj63(x) && obj63(hd(x)) && hd(hd(x)) === "%function";
+  return hd63(x, function (x) {
+    return hd63(x, "%function");
+  });
 };
 setenv("do", {_stash: true, special: function () {
   var __forms1 = unstash(Array.prototype.slice.call(arguments, 0));
@@ -1103,10 +1105,8 @@ setenv("do", {_stash: true, special: function () {
       __s3 = clip(__s3, 0, edge(__s3)) + ";\n";
     }
     __s3 = __s3 + compile(__x137, {_stash: true, stmt: true});
-    if (! atom63(__x137)) {
-      if (hd(__x137) === "return" || hd(__x137) === "break") {
-        break;
-      }
+    if (hd63(__x137, "return") || hd63(__x137, "break")) {
+      break;
     }
     ____i19 = ____i19 + 1;
   }
diff --git a/bin/compiler.lua b/bin/compiler.lua
index c1ba3f0..7d59200 100644
--- a/bin/compiler.lua
+++ b/bin/compiler.lua
@@ -27,7 +27,7 @@ local function special63(k)
   return is63(getenv(k, "special"))
 end
 local function special_form63(form)
-  return not atom63(form) and special63(hd(form))
+  return hd63(form, special63)
 end
 local function statement63(k)
   return special63(k) and getenv(k, "stmt")
@@ -176,7 +176,7 @@ local function can_unquote63(depth)
   return quoting63(depth) and depth == 1
 end
 local function quasisplice63(x, depth)
-  return can_unquote63(depth) and not atom63(x) and hd(x) == "unquote-splicing"
+  return can_unquote63(depth) and hd63(x, "unquote-splicing")
 end
 local function expand_local(__x38)
   local ____id1 = __x38
@@ -522,7 +522,7 @@ local function infix63(x)
   return is63(getop(x))
 end
 function infix_operator63(x)
-  return obj63(x) and infix63(hd(x))
+  return hd63(x, infix63)
 end
 local function compile_args(args)
   local __s1 = "("
@@ -629,7 +629,7 @@ local function compile_special(form, stmt63)
   return apply(__special, __args2) .. __tr
 end
 local function parenthesize_call63(x)
-  return not atom63(x) and hd(x) == "%function" or precedence(x) > 0
+  return hd63(x, "%function") or precedence(x) > 0
 end
 local function compile_call(form)
   local __f = hd(form)
@@ -757,7 +757,7 @@ function compile(form, ...)
         __e37 = compile_atom(__form)
       else
         local __e38 = nil
-        if infix63(hd(__form)) then
+        if infix_operator63(__form) then
           __e38 = compile_infix(__form)
         else
           __e38 = compile_call(__form)
@@ -799,7 +799,7 @@ local function literal63(form)
   return atom63(form) or hd(form) == "%array" or hd(form) == "%object"
 end
 local function standalone63(form)
-  return not atom63(form) and not infix63(hd(form)) and not literal63(form) and not( "get" == hd(form)) or id_literal63(form)
+  return not atom63(form) and not infix_operator63(form) and not literal63(form) and not hd63(form, "get") or id_literal63(form)
 end
 local function lower_do(args, hoist, stmt63, tail63)
   local ____x98 = almost(args)
@@ -938,7 +938,7 @@ local function lower_pairwise(form)
   end
 end
 local function lower_infix63(form)
-  return infix63(hd(form)) and _35(form) > 3
+  return infix_operator63(form) and _35(form) > 3
 end
 local function lower_infix(form, hoist)
   local __form3 = lower_pairwise(form)
@@ -1043,7 +1043,9 @@ function _eval(form)
   return _37result
 end
 function immediate_call63(x)
-  return obj63(x) and obj63(hd(x)) and hd(hd(x)) == "%function"
+  return hd63(x, function (x)
+    return hd63(x, "%function")
+  end)
 end
 setenv("do", {_stash = true, special = function (...)
   local __forms1 = unstash({...})
@@ -1056,10 +1058,8 @@ setenv("do", {_stash = true, special = function (...)
       __s3 = clip(__s3, 0, edge(__s3)) .. ";\n"
     end
     __s3 = __s3 .. compile(__x141, {_stash = true, stmt = true})
-    if not atom63(__x141) then
-      if hd(__x141) == "return" or hd(__x141) == "break" then
-        break
-      end
+    if hd63(__x141, "return") or hd63(__x141, "break") then
+      break
     end
     ____i19 = ____i19 + 1
   end
diff --git a/bin/lumen.js b/bin/lumen.js
index f760831..dc44614 100644
--- a/bin/lumen.js
+++ b/bin/lumen.js
@@ -62,7 +62,20 @@ atom63 = function (x) {
   return nil63(x) || string63(x) || number63(x) || boolean63(x);
 };
 hd63 = function (l, x) {
-  return obj63(l) && hd(l) === x;
+  var __id2 = obj63(l);
+  var __e1 = undefined;
+  if (__id2) {
+    var __e2 = undefined;
+    if (function63(x)) {
+      __e2 = x(hd(l));
+    } else {
+      __e2 = hd(l) === x;
+    }
+    __e1 = __e2;
+  } else {
+    __e1 = __id2;
+  }
+  return __e1;
 };
 nan = 0 / 0;
 inf = 1 / 0;
@@ -79,21 +92,21 @@ clip = function (s, from, upto) {
 cut = function (x, from, upto) {
   var __l = [];
   var __j = 0;
-  var __e = undefined;
+  var __e3 = undefined;
   if (nil63(from) || from < 0) {
-    __e = 0;
+    __e3 = 0;
   } else {
-    __e = from;
+    __e3 = from;
   }
-  var __i = __e;
+  var __i = __e3;
   var __n = _35(x);
-  var __e1 = undefined;
+  var __e4 = undefined;
   if (nil63(upto) || upto > __n) {
-    __e1 = __n;
+    __e4 = __n;
   } else {
-    __e1 = upto;
+    __e4 = upto;
   }
-  var __upto = __e1;
+  var __upto = __e4;
   while (__i < __upto) {
     __l[__j] = x[__i];
     __i = __i + 1;
@@ -103,13 +116,13 @@ cut = function (x, from, upto) {
   var __k = undefined;
   for (__k in ____o) {
     var __v = ____o[__k];
-    var __e2 = undefined;
+    var __e5 = undefined;
     if (numeric63(__k)) {
-      __e2 = parseInt(__k);
+      __e5 = parseInt(__k);
     } else {
-      __e2 = __k;
+      __e5 = __k;
     }
-    var __k1 = __e2;
+    var __k1 = __e5;
     if (! number63(__k1)) {
       __l[__k1] = __v;
     }
@@ -122,13 +135,13 @@ keys = function (x) {
   var __k2 = undefined;
   for (__k2 in ____o1) {
     var __v1 = ____o1[__k2];
-    var __e3 = undefined;
+    var __e6 = undefined;
     if (numeric63(__k2)) {
-      __e3 = parseInt(__k2);
+      __e6 = parseInt(__k2);
     } else {
-      __e3 = __k2;
+      __e6 = __k2;
     }
-    var __k3 = __e3;
+    var __k3 = __e6;
     if (! number63(__k3)) {
       __t[__k3] = __v1;
     }
@@ -202,13 +215,13 @@ join = function () {
       var __k4 = undefined;
       for (__k4 in ____o2) {
         var __v2 = ____o2[__k4];
-        var __e4 = undefined;
+        var __e7 = undefined;
         if (numeric63(__k4)) {
-          __e4 = parseInt(__k4);
+          __e7 = parseInt(__k4);
         } else {
-          __e4 = __k4;
+          __e7 = __k4;
         }
-        var __k5 = __e4;
+        var __k5 = __e7;
         if (number63(__k5)) {
           __k5 = __k5 + __n3;
         }
@@ -224,13 +237,13 @@ find = function (f, t) {
   var ____i6 = undefined;
   for (____i6 in ____o3) {
     var __x2 = ____o3[____i6];
-    var __e5 = undefined;
+    var __e8 = undefined;
     if (numeric63(____i6)) {
-      __e5 = parseInt(____i6);
+      __e8 = parseInt(____i6);
     } else {
-      __e5 = ____i6;
+      __e8 = ____i6;
     }
-    var ____i61 = __e5;
+    var ____i61 = __e8;
     var __y = f(__x2);
     if (__y) {
       return __y;
@@ -265,9 +278,9 @@ pair = function (l) {
   return __l12;
 };
 sort = function (l, f) {
-  var __e6 = undefined;
+  var __e9 = undefined;
   if (f) {
-    __e6 = function (a, b) {
+    __e9 = function (a, b) {
       if (f(a, b)) {
         return -1;
       } else {
@@ -275,7 +288,7 @@ sort = function (l, f) {
       }
     };
   }
-  return l.sort(__e6);
+  return l.sort(__e9);
 };
 map = function (f, x) {
   var __t1 = [];
@@ -293,13 +306,13 @@ map = function (f, x) {
   var __k6 = undefined;
   for (__k6 in ____o4) {
     var __v4 = ____o4[__k6];
-    var __e7 = undefined;
+    var __e10 = undefined;
     if (numeric63(__k6)) {
-      __e7 = parseInt(__k6);
+      __e10 = parseInt(__k6);
     } else {
-      __e7 = __k6;
+      __e10 = __k6;
     }
-    var __k7 = __e7;
+    var __k7 = __e10;
     if (! number63(__k7)) {
       var __y3 = f(__v4);
       if (is63(__y3)) {
@@ -321,13 +334,13 @@ keys63 = function (t) {
   var __k8 = undefined;
   for (__k8 in ____o5) {
     var __v5 = ____o5[__k8];
-    var __e8 = undefined;
+    var __e11 = undefined;
     if (numeric63(__k8)) {
-      __e8 = parseInt(__k8);
+      __e11 = parseInt(__k8);
     } else {
-      __e8 = __k8;
+      __e11 = __k8;
     }
-    var __k9 = __e8;
+    var __k9 = __e11;
     if (! number63(__k9)) {
       return true;
     }
@@ -339,13 +352,13 @@ empty63 = function (t) {
   var ____i12 = undefined;
   for (____i12 in ____o6) {
     var __x7 = ____o6[____i12];
-    var __e9 = undefined;
+    var __e12 = undefined;
     if (numeric63(____i12)) {
-      __e9 = parseInt(____i12);
+      __e12 = parseInt(____i12);
     } else {
-      __e9 = ____i12;
+      __e12 = ____i12;
     }
-    var ____i121 = __e9;
+    var ____i121 = __e12;
     return false;
   }
   return true;
@@ -357,13 +370,13 @@ stash = function (args) {
     var __k10 = undefined;
     for (__k10 in ____o7) {
       var __v6 = ____o7[__k10];
-      var __e10 = undefined;
+      var __e13 = undefined;
       if (numeric63(__k10)) {
-        __e10 = parseInt(__k10);
+        __e13 = parseInt(__k10);
       } else {
-        __e10 = __k10;
+        __e13 = __k10;
       }
-      var __k11 = __e10;
+      var __k11 = __e13;
       if (! number63(__k11)) {
         __p[__k11] = __v6;
       }
@@ -384,13 +397,13 @@ unstash = function (args) {
       var __k12 = undefined;
       for (__k12 in ____o8) {
         var __v7 = ____o8[__k12];
-        var __e11 = undefined;
+        var __e14 = undefined;
         if (numeric63(__k12)) {
-          __e11 = parseInt(__k12);
+          __e14 = parseInt(__k12);
         } else {
-          __e11 = __k12;
+          __e14 = __k12;
         }
-        var __k13 = __e11;
+        var __k13 = __e14;
         if (!( __k13 === "_stash")) {
           __args1[__k13] = __v7;
         }
@@ -407,13 +420,13 @@ destash33 = function (l, args1) {
     var __k14 = undefined;
     for (__k14 in ____o9) {
       var __v8 = ____o9[__k14];
-      var __e12 = undefined;
+      var __e15 = undefined;
       if (numeric63(__k14)) {
-        __e12 = parseInt(__k14);
+        __e15 = parseInt(__k14);
       } else {
-        __e12 = __k14;
+        __e15 = __k14;
       }
-      var __k15 = __e12;
+      var __k15 = __e15;
       if (!( __k15 === "_stash")) {
         args1[__k15] = __v8;
       }
@@ -553,31 +566,31 @@ escape = function (s) {
   var __i20 = 0;
   while (__i20 < _35(s)) {
     var __c = char(s, __i20);
-    var __e13 = undefined;
+    var __e16 = undefined;
     if (__c === "\n") {
-      __e13 = "\\n";
+      __e16 = "\\n";
     } else {
-      var __e14 = undefined;
+      var __e17 = undefined;
       if (__c === "\r") {
-        __e14 = "\\r";
+        __e17 = "\\r";
       } else {
-        var __e15 = undefined;
+        var __e18 = undefined;
         if (__c === "\"") {
-          __e15 = "\\\"";
+          __e18 = "\\\"";
         } else {
-          var __e16 = undefined;
+          var __e19 = undefined;
           if (__c === "\\") {
-            __e16 = "\\\\";
+            __e19 = "\\\\";
           } else {
-            __e16 = __c;
+            __e19 = __c;
           }
-          __e15 = __e16;
+          __e18 = __e19;
         }
-        __e14 = __e15;
+        __e17 = __e18;
       }
-      __e13 = __e14;
+      __e16 = __e17;
     }
-    var __c1 = __e13;
+    var __c1 = __e16;
     __s1 = __s1 + __c1;
     __i20 = __i20 + 1;
   }
@@ -628,13 +641,13 @@ str = function (x, stack) {
                       var __k16 = undefined;
                       for (__k16 in ____o10) {
                         var __v9 = ____o10[__k16];
-                        var __e17 = undefined;
+                        var __e20 = undefined;
                         if (numeric63(__k16)) {
-                          __e17 = parseInt(__k16);
+                          __e20 = parseInt(__k16);
                         } else {
-                          __e17 = __k16;
+                          __e20 = __k16;
                         }
-                        var __k17 = __e17;
+                        var __k17 = __e20;
                         if (number63(__k17)) {
                           __xs11[__k17] = str(__v9, __l4);
                         } else {
@@ -647,13 +660,13 @@ str = function (x, stack) {
                       var ____i22 = undefined;
                       for (____i22 in ____o11) {
                         var __v10 = ____o11[____i22];
-                        var __e18 = undefined;
+                        var __e21 = undefined;
                         if (numeric63(____i22)) {
-                          __e18 = parseInt(____i22);
+                          __e21 = parseInt(____i22);
                         } else {
-                          __e18 = ____i22;
+                          __e21 = ____i22;
                         }
-                        var ____i221 = __e18;
+                        var ____i221 = __e21;
                         __s = __s + __sp + __v10;
                         __sp = " ";
                       }
@@ -686,25 +699,25 @@ setenv = function (k) {
   var ____id1 = ____r76;
   var __keys = cut(____id1, 0);
   if (string63(__k18)) {
-    var __e19 = undefined;
+    var __e22 = undefined;
     if (__keys.toplevel) {
-      __e19 = hd(environment);
+      __e22 = hd(environment);
     } else {
-      __e19 = last(environment);
+      __e22 = last(environment);
     }
-    var __frame = __e19;
+    var __frame = __e22;
     var __entry = __frame[__k18] || {};
     var ____o12 = __keys;
     var __k19 = undefined;
     for (__k19 in ____o12) {
       var __v11 = ____o12[__k19];
-      var __e20 = undefined;
+      var __e23 = undefined;
       if (numeric63(__k19)) {
-        __e20 = parseInt(__k19);
+        __e23 = parseInt(__k19);
       } else {
-        __e20 = __k19;
+        __e23 = __k19;
       }
-      var __k20 = __e20;
+      var __k20 = __e23;
       __entry[__k20] = __v11;
     }
     __frame[__k18] = __entry;
diff --git a/bin/lumen.lua b/bin/lumen.lua
index 6478c38..4a1908e 100644
--- a/bin/lumen.lua
+++ b/bin/lumen.lua
@@ -59,7 +59,20 @@ function atom63(x)
   return nil63(x) or string63(x) or number63(x) or boolean63(x)
 end
 function hd63(l, x)
-  return obj63(l) and hd(l) == x
+  local __id2 = obj63(l)
+  local __e1 = nil
+  if __id2 then
+    local __e2 = nil
+    if function63(x) then
+      __e2 = x(hd(l))
+    else
+      __e2 = hd(l) == x
+    end
+    __e1 = __e2
+  else
+    __e1 = __id2
+  end
+  return __e1
 end
 nan = 0 / 0
 inf = 1 / 0
@@ -76,21 +89,21 @@ end
 function cut(x, from, upto)
   local __l = {}
   local __j = 0
-  local __e = nil
+  local __e3 = nil
   if nil63(from) or from < 0 then
-    __e = 0
+    __e3 = 0
   else
-    __e = from
+    __e3 = from
   end
-  local __i = __e
+  local __i = __e3
   local __n = _35(x)
-  local __e1 = nil
+  local __e4 = nil
   if nil63(upto) or upto > __n then
-    __e1 = __n
+    __e4 = __n
   else
-    __e1 = upto
+    __e4 = upto
   end
-  local __upto = __e1
+  local __upto = __e4
   while __i < __upto do
     __l[__j + 1] = x[__i + 1]
     __i = __i + 1
@@ -131,11 +144,11 @@ function char(s, n)
   return clip(s, n, n + 1)
 end
 function code(s, n)
-  local __e2 = nil
+  local __e5 = nil
   if n then
-    __e2 = n + 1
+    __e5 = n + 1
   end
-  return string.byte(s, __e2)
+  return string.byte(s, __e5)
 end
 function string_literal63(x)
   return string63(x) and char(x, 0) == "\""
@@ -344,11 +357,11 @@ function destash33(l, args1)
   end
 end
 function search(s, pattern, start)
-  local __e3 = nil
+  local __e6 = nil
   if start then
-    __e3 = start + 1
+    __e6 = start + 1
   end
-  local __start = __e3
+  local __start = __e6
   local __i16 = string.find(s, pattern, __start, true)
   return __i16 and __i16 - 1
 end
@@ -471,31 +484,31 @@ function escape(s)
   local __i20 = 0
   while __i20 < _35(s) do
     local __c = char(s, __i20)
-    local __e4 = nil
+    local __e7 = nil
     if __c == "\n" then
-      __e4 = "\\n"
+      __e7 = "\\n"
     else
-      local __e5 = nil
+      local __e8 = nil
       if __c == "\r" then
-        __e5 = "\\r"
+        __e8 = "\\r"
       else
-        local __e6 = nil
+        local __e9 = nil
         if __c == "\"" then
-          __e6 = "\\\""
+          __e9 = "\\\""
         else
-          local __e7 = nil
+          local __e10 = nil
           if __c == "\\" then
-            __e7 = "\\\\"
+            __e10 = "\\\\"
           else
-            __e7 = __c
+            __e10 = __c
           end
-          __e6 = __e7
+          __e9 = __e10
         end
-        __e5 = __e6
+        __e8 = __e9
       end
-      __e4 = __e5
+      __e7 = __e8
     end
-    local __c1 = __e4
+    local __c1 = __e7
     __s1 = __s1 .. __c1
     __i20 = __i20 + 1
   end
@@ -594,13 +607,13 @@ function setenv(k, ...)
   local ____id1 = ____r73
   local __keys = cut(____id1, 0)
   if string63(__k9) then
-    local __e8 = nil
+    local __e11 = nil
     if __keys.toplevel then
-      __e8 = hd(environment)
+      __e11 = hd(environment)
     else
-      __e8 = last(environment)
+      __e11 = last(environment)
     end
-    local __frame = __e8
+    local __frame = __e11
     local __entry = __frame[__k9] or {}
     local ____o12 = __keys
     local __k10 = nil
diff --git a/compiler.l b/compiler.l
index de2bbbd..59b5120 100644
--- a/compiler.l
+++ b/compiler.l
@@ -17,7 +17,7 @@
   (is? (getenv k 'special)))
 
 (define special-form? (form)
-  (and (not (atom? form)) (special? (hd form))))
+  (hd? form special?))
 
 (define statement? (k)
   (and (special? k) (getenv k 'stmt)))
@@ -115,8 +115,7 @@
 
 (define quasisplice? (x depth)
   (and (can-unquote? depth)
-       (not (atom? x))
-       (= (hd x) 'unquote-splicing)))
+       (hd? x 'unquote-splicing)))
 
 (define expand-local ((x name value))
   (setenv name :variable)
@@ -306,7 +305,7 @@
   (is? (getop x)))
 
 (define-global infix-operator? (x)
-  (and (obj? x) (infix? (hd x))))
+  (hd? x infix?))
 
 (define compile-args (args)
   (let (s "(" c "")
@@ -348,8 +347,7 @@
     (cat (apply special args) tr)))
 
 (define parenthesize-call? (x)
-  (or (and (not (atom? x))
-           (= (hd x) '%function))
+  (or (hd? x '%function)
       (> (precedence x) 0)))
 
 (define compile-call (form)
@@ -407,7 +405,7 @@
     (let (tr (terminator stmt)
           ind (if stmt (indentation) "")
           form (if (atom? form) (compile-atom form)
-                   (infix? (hd form)) (compile-infix form)
+                   (infix-operator? form) (compile-infix form)
                  (compile-call form)))
       (cat ind form tr))))
 
@@ -431,9 +429,9 @@
 
 (define standalone? (form)
   (or (and (not (atom? form))
-           (not (infix? (hd form)))
+           (not (infix-operator? form))
            (not (literal? form))
-           (not (= 'get (hd form))))
+           (not (hd? form 'get)))
       (id-literal? form)))
 
 (define lower-do (args hoist stmt? tail?)
@@ -530,7 +528,7 @@
     form))
 
 (define lower-infix? (form)
-  (and (infix? (hd form)) (> (# form) 3)))
+  (and (infix-operator? form) (> (# form) 3)))
 
 (define lower-infix (form hoist)
   (let (form (lower-pairwise form)
@@ -589,7 +587,7 @@
       %result)))
 
 (define-global immediate-call? (x)
-  (and (obj? x) (obj? (hd x)) (= (hd (hd x)) '%function)))
+  (hd? x (fn (x) (hd? x '%function))))
 
 (define-special do forms :stmt :tr
   (with s ""
@@ -599,10 +597,9 @@
                  (= "\n" (char s (edge s))))
         (set s (cat (clip s 0 (edge s)) ";\n")))
       (cat! s (compile x :stmt))
-      (unless (atom? x)
-        (if (or (= (hd x) 'return)
-                (= (hd x) 'break))
-            (break))))))
+      (when (or (hd? x 'return)
+                (hd? x 'break))
+        (break)))))
 
 (define-special %if (cond cons alt) :stmt :tr
   (let (cond (compile cond)
diff --git a/runtime.l b/runtime.l
index 50951c8..322f2cf 100644
--- a/runtime.l
+++ b/runtime.l
@@ -41,7 +41,10 @@
   (or (nil? x) (string? x) (number? x) (boolean? x)))
 
 (define-global hd? (l x)
-  (and (obj? l) (= (hd l) x)))
+  (and (obj? l)
+       (if (function? x)
+           (x (hd l))
+         (= (hd l) x))))
 
 (define-global nan (/ 0 0))
 (define-global inf (/ 1 0))