slight optimization of expression type determination

Builtin.pm

@@ -316,10 +316,11 @@ sub Blet_star {
                         ($def, $defs) = cxr($defs);
                         my $var;
                         my $value;
-                        if (symbolp($def)) {
+                        my $type = type_of($def);
+                        if ($type eq "Symbol") {
                                 $var = $def;
                                 $value = $Nil;
-                        } elsif (consp($def)) {
+                        } elsif ($type eq "Pair") {
                                 $var = is_sym(car($def));
                                 $value = Eval(is_def(cadr($def)));
                         } else {
@@ -358,10 +359,11 @@ sub Blet {
                         ($def, $defs) = cxr($defs);
                         my $var;
                         my $value;
-                        if (symbolp($def)) {
+                        my $type = type_of($def);
+                        if ($type eq "Symbol") {
                                 $var = $def;
                                 $value = $Nil;
-                        } elsif (consp($def)) {
+                        } elsif ($type eq "Pair") {
                                 $var = is_sym(car($def));
                                 $value = Eval(is_def(cadr($def)));
                         } else {
@@ -860,13 +862,10 @@ sub Bfmakunbound {
 
 sub Btype_of {
         my ($ob) = checkargs($_[0], 'e');
-        if (symbolp($ob)) {
-                return $t_Symbol;
-        } elsif (consp($ob)) {
-                return $t_Pair;
-        } elsif (functionp($ob)) {
-                return $t_Function;
-        } elsif (numberp($ob)) {
+        my $type = type_of($ob);
+        return intern(lc($type)) unless $type eq "scalar";
+        
+        if (numberp($ob)) {
                 return $t_Number;
         } else {
                 return $t_String;

Eval.pm

@@ -204,13 +204,14 @@ sub evalfun {
 
         my $result;
         while (--$max) {
-                if (functionp($ob)) {
+                my $type = type_of($ob);
+                if ($type eq "Function") {
                         #debugl("evalfun function: %s", $ob);
-                        $result =  $ob;
+                        $result = $ob;
                         last;
                 } elsif (is_nil($ob)) {
                         return error("nil function %s", $orig);
-                } elsif (symbolp($ob)) {
+                } elsif ($type eq "Symbol") {
                         my $symbol = $ob;
                         if (my $func = symbol_function($ob)) {
                                 $ob = $func;
@@ -224,14 +225,14 @@ sub evalfun {
                         return error("undefined function %s",
                                      symbol_name($symbol))
                             unless defined($ob);
-                } elsif (consp($ob)) {
+                } elsif ($type eq "Pair") {
                         my $form = $ob;
                         $ob = Eval($ob);
                         #debugl("evalfun form %s returns %s", $form, $ob);
                         return error("function form yields undefined: %s",
                                      $form)
                             unless defined($ob);
-                } elsif (!defined($ob)) {
+                } elsif ($type eq "undef") {
                         return error("undefined function %s", $orig);
                 } else {
                         return error("not a function: %s", $orig);
@@ -255,12 +256,13 @@ sub Eval {
         $eval_depth++;
         $eval_counter++;
         my $result;
-        if (symbolp($ob)) {
+        my $type = type_of($ob);
+        if ($type eq "Symbol") {
                 #debugl("expr is sym: %s", $ob);
                 $result = symbol_value($ob);
                 return error("unbound variable %s", symbol_name($ob))
                     unless defined($result);
-        } elsif (consp($ob)) {
+        } elsif ($type eq "Pair") {
                 #debugl("expr is cons: %s", $ob);
                 my $func = evalfun(car($ob));
                 my $args = cdr($ob);

Sexp.pm

@@ -17,7 +17,7 @@ use Exporter ();
 BEGIN {
         @ISA = qw(Exporter);
         @EXPORT = qw( intern cons list car cdr listp symbolp numberp stringp
-                      consp symbol_name symbol_function functionp cxr
+                      consp symbol_name symbol_function functionp cxr type_of
                       rplaca rplacd fset function put get symbol_plist
                       specialp caar cadr cdar cddr caaar caadr cadar caddr cdaar
                       cdadr cddar cdddr function_type function_code symbol_value
@@ -89,6 +89,12 @@ sub function_documentation {
         return $ob->{doc};
 }
 
+sub type_of {
+        my ($ob) = @_;
+        return "undef" unless defined($ob);
+        return ref($ob) || "scalar";
+}
+
 sub function {
         my ($func, $is_special, $doc, $name) = @_;
         my $type;