diff --git a/PTask.h b/PTask.h
index b06375dfc..4cd6a9a22 100644
--- a/PTask.h
+++ b/PTask.h
@@ -1,7 +1,7 @@
 #ifndef __PTask_H
 #define __PTask_H
 /*
- * Copyright (c) 1999-2008,2010 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 1999-2008,2010,2012 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -46,7 +46,7 @@ enum PTaskFuncEnum {
 
 struct PTaskFuncArg {
       PTaskFuncEnum type;
-      vector<PExpr*>*range;
+      std::list<index_component_t>*range;
 };
 
 /*
diff --git a/elab_scope.cc b/elab_scope.cc
index a93c9a08c..efce812c6 100644
--- a/elab_scope.cc
+++ b/elab_scope.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2011 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2000-2012 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -133,9 +133,10 @@ static void elaborate_scope_enumeration(Design*des, NetScope*scope,
 					enum_type_t*enum_type)
 {
       bool rc_flag;
-      assert(enum_type->range->size() == 2);
-      NetExpr*msb_ex = elab_and_eval(des, scope, enum_type->range->front(), -1);
-      NetExpr*lsb_ex = elab_and_eval(des, scope, enum_type->range->back(),  -1);
+      assert(enum_type->range->size() == 1);
+      index_component_t index = enum_type->range->front();
+      NetExpr*msb_ex = elab_and_eval(des, scope, index.msb, -1);
+      NetExpr*lsb_ex = elab_and_eval(des, scope, index.lsb,  -1);
 
       long msb = 0;
       rc_flag = eval_as_long(msb, msb_ex);
diff --git a/elab_sig.cc b/elab_sig.cc
index 42ed8c355..1a00cb786 100644
--- a/elab_sig.cc
+++ b/elab_sig.cc
@@ -476,15 +476,12 @@ void PFunction::elaborate_sig(Design*des, NetScope*scope) const
 	  case PTF_REG:
 	  case PTF_REG_S:
 	    if (return_type_.range) {
-		  ivl_assert(*this, return_type_.range->size() == 2);
+		  ivl_assert(*this, return_type_.range->size() == 1);
+		  index_component_t index = return_type_.range->front();
 
-		  NetExpr*me = elab_and_eval(des, scope,
-					     return_type_.range->at(0), -1,
-                                             true);
+		  NetExpr*me = elab_and_eval(des, scope, index.msb, -1, true);
 		  assert(me);
-		  NetExpr*le = elab_and_eval(des, scope,
-					     return_type_.range->at(1), -1,
-                                             true);
+		  NetExpr*le = elab_and_eval(des, scope, index.lsb, -1, true);
 		  assert(le);
 
 		  long mnum = 0, lnum = 0;
@@ -550,17 +547,14 @@ void PFunction::elaborate_sig(Design*des, NetScope*scope) const
 
 	  case PTF_ATOM2:
 	  case PTF_ATOM2_S:
-	    ivl_assert(*this, return_type_.range != 0);
 	    long use_wid;
 	    {
-		  NetExpr*me = elab_and_eval(des, scope,
-					     (*return_type_.range)[0], -1,
-                                             true);
-		  assert(me);
-		  NetExpr*le = elab_and_eval(des, scope,
-					     (*return_type_.range)[1], -1,
-                                             true);
-		  assert(le);
+		  ivl_assert(*this, return_type_.range->size() == 1);
+		  index_component_t index = return_type_.range->front();
+		  NetExpr*me = elab_and_eval(des, scope, index.msb, -1, true);
+		  ivl_assert(*this, me);
+		  NetExpr*le = elab_and_eval(des, scope, index.lsb, -1, true);
+		  ivl_assert(*this, le);
 
 		  long mnum = 0, lnum = 0;
 		  if ( ! get_const_argument(me, mnum) ) {
@@ -805,9 +799,10 @@ static netstruct_t* elaborate_struct_type(Design*des, NetScope*scope,
 	    long use_msb = 0;
 	    long use_lsb = 0;
 	    if (curp->range.get() && ! curp->range->empty()) {
-		  ivl_assert(*curp, curp->range->size() == 2);
-		  PExpr*msb_pex = curp->range->front();
-		  PExpr*lsb_pex = curp->range->back();
+		  ivl_assert(*curp, curp->range->size() == 1);
+		  index_component_t index = curp->range->front();
+		  PExpr*msb_pex = index.msb;
+		  PExpr*lsb_pex = index.lsb;
 
 		  NetExpr*tmp = elab_and_eval(des, scope, msb_pex, -2, true);
 		  ivl_assert(*curp, tmp);
diff --git a/parse.y b/parse.y
index 02a458b28..411875217 100644
--- a/parse.y
+++ b/parse.y
@@ -38,7 +38,7 @@ extern void lex_end_table();
 bool have_timeunit_decl = false;
 bool have_timeprec_decl = false;
 
-static list<PExpr*>* param_active_range = 0;
+static list<index_component_t>* param_active_range = 0;
 static bool param_active_signed = false;
 static ivl_variable_type_t param_active_type = IVL_VT_LOGIC;
 
@@ -48,7 +48,7 @@ static struct {
       NetNet::PortType port_type;
       ivl_variable_type_t var_type;
       bool sign_flag;
-      list<PExpr*>* range;
+      list<index_component_t>* range;
       data_type_t* data_type;
 } port_declaration_context = {NetNet::NONE, NetNet::NOT_A_PORT,
                               IVL_VT_NO_TYPE, false, 0, 0};
@@ -98,8 +98,7 @@ static list<pair<perm_string,PExpr*> >* make_port_list(char*id, PExpr*expr)
       delete[]id;
       return tmp;
 }
-static list<pair<perm_string,PExpr*> >* make_port_list(list<pair<perm_string,
-                                                                 PExpr*> >*tmp,
+static list<pair<perm_string,PExpr*> >* make_port_list(list<pair<perm_string, PExpr*> >*tmp,
                                                        char*id, PExpr*expr)
 {
       tmp->push_back(make_pair(lex_strings.make(id), expr));
@@ -107,16 +106,19 @@ static list<pair<perm_string,PExpr*> >* make_port_list(list<pair<perm_string,
       return tmp;
 }
 
-list<PExpr*>* make_range_from_width(uint64_t wid)
+list<index_component_t>* make_range_from_width(uint64_t wid)
 {
-      list<PExpr*>*range = new list<PExpr*>;
+      list<index_component_t>*range = new list<index_component_t>;
 
-      range->push_back(new PENumber(new verinum(wid-1, integer_width)));
-      range->push_back(new PENumber(new verinum((uint64_t)0, integer_width)));
+      index_component_t tmp;
+      tmp.msb = new PENumber(new verinum(wid-1, integer_width));
+      tmp.lsb = new PENumber(new verinum((uint64_t)0, integer_width));
+      range->push_back(tmp);
 
       return range;
 }
 
+#if 0
 /*
  * Make a range vector from an existing pair of expressions.
  */
@@ -129,7 +131,8 @@ static vector<PExpr*>* make_range_vector(list<PExpr*>*that)
       delete that;
       return tmp;
 }
-
+#endif
+#if 0
 /*
  * Make a range vector from a width. Generate the msb and lsb
  * expressions to get the canonical range for the given width.
@@ -141,7 +144,7 @@ static vector<PExpr*>* make_range_vector(uint64_t wid)
       tmp->at(1) = new PENumber(new verinum((uint64_t)0, integer_width));
       return tmp;
 }
-
+#endif
 static list<perm_string>* list_from_identifier(char*id)
 {
       list<perm_string>*tmp = new list<perm_string>;
@@ -157,12 +160,12 @@ static list<perm_string>* list_from_identifier(list<perm_string>*tmp, char*id)
       return tmp;
 }
 
-list<PExpr*>* copy_range(list<PExpr*>* orig)
+list<index_component_t>* copy_range(list<index_component_t>* orig)
 {
-      list<PExpr*>*copy = 0;
+      list<index_component_t>*copy = 0;
 
       if (orig)
-	    copy = new list<PExpr*> (*orig);
+	    copy = new list<index_component_t> (*orig);
 
       return copy;
 }
@@ -512,8 +515,8 @@ static void current_task_set_statement(vector<Statement*>*s)
 %type <struct_members> struct_union_member_list
 %type <struct_type>    struct_data_type
 
-%type <exprs> range range_opt variable_dimension
-%type <dimensions> dimensions_opt dimensions
+%type <dimensions> range range_opt
+%type <dimensions> dimensions_opt dimensions variable_dimension
 %type <nettype>  net_type var_type net_type_opt
 %type <gatetype> gatetype switchtype
 %type <porttype> port_direction port_direction_opt
@@ -1015,13 +1018,6 @@ variable_decl_assignment /* IEEE1800-2005 A.2.3 */
 	delete[]$1;
 	$$ = tmp;
       }
-  | IDENTIFIER '[' ']'
-      { decl_assignment_t*tmp = new decl_assignment_t;
-	tmp->name = lex_strings.make($1);
-	yyerror("sorry: Dynamic arrays not yet supported here.");
-	delete[]$1;
-	$$ = tmp;
-      }
   | IDENTIFIER '[' '$' ']'
       { decl_assignment_t*tmp = new decl_assignment_t;
 	tmp->name = lex_strings.make($1);
@@ -1272,7 +1268,7 @@ tf_port_item /* IEEE1800-2005: A.2.7 */
   /* Ports can be integer with a width of [31:0]. */
 
   : port_direction_opt K_integer IDENTIFIER range_opt tf_port_item_expr_opt
-      { list<PExpr*>*range_stub = make_range_from_width(integer_width);
+      { list<index_component_t>*range_stub = make_range_from_width(integer_width);
 	NetNet::PortType use_port_type = $1==NetNet::PIMPLICIT? NetNet::PINPUT : $1;
 
 	port_declaration_context.port_type = use_port_type;
@@ -1297,7 +1293,7 @@ tf_port_item /* IEEE1800-2005: A.2.7 */
   /* Ports can be time with a width of [63:0] (unsigned). */
 
   | port_direction_opt K_time IDENTIFIER range_opt tf_port_item_expr_opt
-      { list<PExpr*>*range_stub = make_range_from_width(64);
+      { list<index_component_t>*range_stub = make_range_from_width(64);
 	NetNet::PortType use_port_type = $1==NetNet::PIMPLICIT? NetNet::PINPUT : $1;
 
 	port_declaration_context.port_type = use_port_type;
@@ -1414,18 +1410,39 @@ tf_port_list /* IEEE1800-2005: A.2.7 */
 
 variable_dimension /* IEEE1800-2005: A.2.5 */
   : '[' expression ':' expression ']'
-      { list<PExpr*>*tmp = new list<PExpr*>;
-	tmp->push_back($2);
-	tmp->push_back($4);
+      { list<index_component_t> *tmp = new list<index_component_t>;
+	index_component_t index;
+	index.sel = index_component_t::SEL_PART;
+	index.msb = $2;
+	index.lsb = $4;
+	tmp->push_back(index);
+	$$ = tmp;
+      }
+  | '[' expression ']'
+      { // SystemVerilog canonical range
+	if (generation_flag < GN_VER2005_SV) {
+	      warn_count += 1;
+	      cerr << @2 << ": warning: Use of SystemVerilog [size] dimension. "
+		   << "Use at least -g2005-sv to remove this warning." << endl;
+	}
+	list<index_component_t> *tmp = new list<index_component_t>;
+	index_component_t index;
+	index.sel = index_component_t::SEL_PART;
+	index.lsb = new PENumber(new verinum((uint64_t)0, integer_width));
+	index.msb = new PEBinary('-', $2, new PENumber(new verinum((uint64_t)1, integer_width)));
+	tmp->push_back(index);
 	$$ = tmp;
       }
   | '[' ']'
-      { list<PExpr*>*tmp = new list<PExpr*>;
-	tmp->push_back(0);
-	tmp->push_back(0);
+      { list<index_component_t> *tmp = new list<index_component_t>;
+	index_component_t index;
+	index.msb = 0;
+	index.lsb = 0;
+	yyerror("sorry: Dynamic array ranges not supported.");
+	tmp->push_back(index);
 	$$ = tmp;
       }
-;
+  ;
 
   /* Verilog-2001 supports attribute lists, which can be attached to a
      variety of different objects. The syntax inside the (* *) is a
@@ -2822,20 +2839,21 @@ gate_instance
 		  $$ = tmp;
 		}
 
-	| IDENTIFIER range '(' expression_list_with_nuls ')'
-		{ lgate*tmp = new lgate;
-		  list<PExpr*>*rng = $2;
-		  tmp->name = $1;
-		  tmp->parms = $4;
-		  tmp->range[0] = rng->front(); rng->pop_front();
-		  tmp->range[1] = rng->front(); rng->pop_front();
-		  assert(rng->empty());
-		  tmp->file  = @1.text;
-		  tmp->lineno = @1.first_line;
-		  delete[]$1;
-		  delete rng;
-		  $$ = tmp;
-		}
+  | IDENTIFIER range '(' expression_list_with_nuls ')'
+      { lgate*tmp = new lgate;
+	list<index_component_t>*rng = $2;
+	tmp->name = $1;
+	tmp->parms = $4;
+	tmp->range = rng->front();
+	rng->pop_front();
+	assert(rng->empty());
+	tmp->file  = @1.text;
+	tmp->lineno = @1.first_line;
+	delete[]$1;
+	delete rng;
+	$$ = tmp;
+      }
+
 	| '(' expression_list_with_nuls ')'
 		{ lgate*tmp = new lgate;
 		  tmp->name = "";
@@ -2847,50 +2865,50 @@ gate_instance
 
   /* Degenerate modules can have no ports. */
 
-	| IDENTIFIER range
-		{ lgate*tmp = new lgate;
-		  list<PExpr*>*rng = $2;
-		  tmp->name = $1;
-		  tmp->parms = 0;
-		  tmp->parms_by_name = 0;
-		  tmp->range[0] = rng->front(); rng->pop_front();
-		  tmp->range[1] = rng->front(); rng->pop_front();
-		  assert(rng->empty());
-		  tmp->file  = @1.text;
-		  tmp->lineno = @1.first_line;
-		  delete[]$1;
-		  delete rng;
-		  $$ = tmp;
-		}
+  | IDENTIFIER range
+      { lgate*tmp = new lgate;
+	list<index_component_t>*rng = $2;
+	tmp->name = $1;
+	tmp->parms = 0;
+	tmp->parms_by_name = 0;
+	tmp->range = rng->front();
+	rng->pop_front();
+	assert(rng->empty());
+	tmp->file  = @1.text;
+	tmp->lineno = @1.first_line;
+	delete[]$1;
+	delete rng;
+	$$ = tmp;
+      }
 
   /* Modules can also take ports by port-name expressions. */
 
-	| IDENTIFIER '(' port_name_list ')'
-		{ lgate*tmp = new lgate;
-		  tmp->name = $1;
-		  tmp->parms = 0;
-		  tmp->parms_by_name = $3;
-		  tmp->file  = @1.text;
-		  tmp->lineno = @1.first_line;
-		  delete[]$1;
-		  $$ = tmp;
-		}
+  | IDENTIFIER '(' port_name_list ')'
+      { lgate*tmp = new lgate;
+	tmp->name = $1;
+	tmp->parms = 0;
+	tmp->parms_by_name = $3;
+	tmp->file  = @1.text;
+	tmp->lineno = @1.first_line;
+	delete[]$1;
+	$$ = tmp;
+      }
 
-	| IDENTIFIER range '(' port_name_list ')'
-		{ lgate*tmp = new lgate;
-		  list<PExpr*>*rng = $2;
-		  tmp->name = $1;
-		  tmp->parms = 0;
-		  tmp->parms_by_name = $4;
-		  tmp->range[0] = rng->front(); rng->pop_front();
-		  tmp->range[1] = rng->front(); rng->pop_front();
-		  assert(rng->empty());
-		  tmp->file  = @1.text;
-		  tmp->lineno = @1.first_line;
-		  delete[]$1;
-		  delete rng;
-		  $$ = tmp;
-		}
+  | IDENTIFIER range '(' port_name_list ')'
+      { lgate*tmp = new lgate;
+	list<index_component_t>*rng = $2;
+	tmp->name = $1;
+	tmp->parms = 0;
+	tmp->parms_by_name = $4;
+	tmp->range = rng->front();
+	rng->pop_front();
+	assert(rng->empty());
+	tmp->file  = @1.text;
+	tmp->lineno = @1.first_line;
+	delete[]$1;
+	delete rng;
+	$$ = tmp;
+      }
 
 	| IDENTIFIER '(' error ')'
 		{ lgate*tmp = new lgate;
@@ -3143,7 +3161,7 @@ port_declaration
     K_input atom2_type signed_unsigned_opt IDENTIFIER
       { Module::port_t*ptmp;
 	perm_string name = lex_strings.make($5);
-	list<PExpr*>*use_range = make_range_from_width($3);
+	list<index_component_t>*use_range = make_range_from_width($3);
 	ptmp = pform_module_port_reference(name, @2.text,
 					   @2.first_line);
 	pform_module_define_port(@2, name, NetNet::PINPUT,
@@ -3289,7 +3307,7 @@ port_declaration
     K_output atom2_type signed_unsigned_opt IDENTIFIER
       { Module::port_t*ptmp;
 	perm_string name = lex_strings.make($5);
-	list<PExpr*>*use_range = make_range_from_width($3);
+	list<index_component_t>*use_range = make_range_from_width($3);
 	ptmp = pform_module_port_reference(name, @2.text,
 					   @2.first_line);
 	pform_module_define_port(@2, name, NetNet::POUTPUT,
@@ -3308,7 +3326,7 @@ port_declaration
     K_output atom2_type signed_unsigned_opt IDENTIFIER '=' expression
       { Module::port_t*ptmp;
 	perm_string name = lex_strings.make($5);
-	list<PExpr*>*use_range = make_range_from_width($3);
+	list<index_component_t>*use_range = make_range_from_width($3);
 	ptmp = pform_module_port_reference(name, @2.text,
 					   @2.first_line);
 	pform_module_define_port(@2, name, NetNet::POUTPUT,
@@ -4606,9 +4624,13 @@ port_reference_list
   /* The range is a list of variable dimensions. */
 range
   : variable_dimension
+      { $$ = $1; }
   | range variable_dimension
-      { list<PExpr*>*tmp = $1;
-	if ($2) tmp->splice(tmp->end(), *$2);
+      { list<index_component_t>*tmp = $1;
+	if ($2) {
+	      tmp->splice(tmp->end(), *$2);
+	      delete $2;
+	}
 	$$ = tmp;
       }
   ;
@@ -4623,88 +4645,54 @@ dimensions_opt
 	| dimensions { $$ = $1; }
 
 dimensions
-	: '[' expression ':' expression ']'
-		{ list<index_component_t> *tmp = new list<index_component_t>;
-		  index_component_t index;
-		  index.msb = $2;
-		  index.lsb = $4;
-		  tmp->push_back(index);
-		  $$ = tmp;
-		}
-        | '[' expression ']'
-		{ if (generation_flag < GN_VER2005_SV) {
-			warn_count += 1;
-			cerr << @2 << ": warning: Use of SystemVerilog [size] dimension. "
-			     << "Use at least -g2005-sv to remove this warning." << endl;
-		  }
-		  list<index_component_t> *tmp = new list<index_component_t>;
-		  index_component_t index;
-		  index.msb = new PENumber(new verinum((uint64_t)0, integer_width));
-		  index.lsb = new PEBinary('-', $2, new PENumber(new verinum((uint64_t)1, integer_width)));
-		  tmp->push_back(index);
-		  $$ = tmp;
-		}
-	| dimensions '[' expression ':' expression ']'
-		{ list<index_component_t> *tmp = $1;
-		  index_component_t index;
-		  index.msb = $3;
-		  index.lsb = $5;
-		  tmp->push_back(index);
-		  $$ = tmp;
-		}
-        | dimensions '[' expression ']'
-		{ if (generation_flag < GN_VER2005_SV) {
-			warn_count += 1;
-			cerr << @2 << ": warning: Use of SystemVerilog [size] dimension. "
-			     << "Use at least -g2005-sv to remove this warning." << endl;
-		  }
-		  list<index_component_t> *tmp = $1;
-		  index_component_t index;
-		  index.msb = new PENumber(new verinum((uint64_t)0, integer_width));
-		  index.lsb = new PEBinary('-', $3, new PENumber(new verinum((uint64_t)1, integer_width)));
-		  tmp->push_back(index);
-		  $$ = tmp;
-		}
+  : variable_dimension
+      { $$ = $1; }
+  | dimensions variable_dimension
+      { list<index_component_t> *tmp = $1;
+	if ($2) {
+	      tmp->splice(tmp->end(), *$2);
+	      delete $2;
+	}
+	$$ = tmp;
+      }
+  ;
 
   /* This is used to express the return type of a function. */
 function_range_or_type_opt
   : unsigned_signed_opt range_opt
-				{
-				/* the default type is reg unsigned and no range */
-				$$.type = PTF_REG;
-				$$.range = 0;
-				if ($1)
-					$$.type = PTF_REG_S;
-				if ($2)
-					$$.range = make_range_vector($2);
-			}
+      { /* the default type is reg unsigned and no range */
+	$$.type = PTF_REG;
+	$$.range = 0;
+	if ($1)
+	      $$.type = PTF_REG_S;
+	if ($2)
+	      $$.range = $2;
+      }
   | K_reg unsigned_signed_opt range_opt
-			{
-				/* the default type is reg unsigned and no range */
-				$$.type = PTF_REG;
-				$$.range = 0;
-				if ($2)
-					$$.type = PTF_REG_S;
-				if ($3)
-					$$.range = make_range_vector($3);
-			}
+      { /* the default type is reg unsigned and no range */
+	$$.type = PTF_REG;
+	$$.range = 0;
+	if ($2)
+	      $$.type = PTF_REG_S;
+	if ($3)
+	      $$.range = $3;
+      }
   | bit_logic unsigned_signed_opt range_opt
-			{
-				/* the default type is bit/logic unsigned and no range */
-				$$.type  = PTF_REG;
-				$$.range = 0;
-				if ($2)
-					$$.type = PTF_REG_S;
-				if ($3)
-					$$.range = make_range_vector($3);
-			}
+      { /* the default type is bit/logic unsigned and no range */
+	$$.type  = PTF_REG;
+	$$.range = 0;
+	if ($2)
+	      $$.type = PTF_REG_S;
+	if ($3)
+	      $$.range = $3;
+      }
   | K_integer  { $$.range = 0;  $$.type = PTF_INTEGER; }
   | K_real     { $$.range = 0;  $$.type = PTF_REAL; }
   | K_realtime { $$.range = 0;  $$.type = PTF_REALTIME; }
   | K_time     { $$.range = 0;  $$.type = PTF_TIME; }
-  | atom2_type { $$.range = make_range_vector($1); $$.type = PTF_ATOM2_S; }
-  | atom2_type K_signed  { $$.range = make_range_vector($1); $$.type = PTF_ATOM2_S; }
-  | atom2_type K_unsigned { $$.range = make_range_vector($1); $$.type = PTF_ATOM2; }
+  | atom2_type { $$.range = make_range_from_width($1); $$.type = PTF_ATOM2_S; }
+  | atom2_type K_signed  { $$.range = make_range_from_width($1); $$.type = PTF_ATOM2_S; }
+  | atom2_type K_unsigned { $$.range = make_range_from_width($1); $$.type = PTF_ATOM2; }
   ;
 
   /* The register_variable rule is matched only when I am parsing
@@ -5577,7 +5565,7 @@ task_port_item
      shape. Generate a range ([31:0]) to make it work. */
 
   | port_direction K_integer list_of_identifiers ';'
-      { list<PExpr*>*range_stub = make_range_from_width(integer_width);
+      { list<index_component_t>*range_stub = make_range_from_width(integer_width);
 	svector<PWire*>*tmp = pform_make_task_ports(@1, $1, IVL_VT_LOGIC, true,
 						    range_stub, $3, true);
 	$$ = tmp;
@@ -5586,7 +5574,7 @@ task_port_item
   /* Ports can be time with a width of [63:0] (unsigned). */
 
   | port_direction K_time list_of_identifiers ';'
-      { list<PExpr*>*range_stub = make_range_from_width(64);
+      { list<index_component_t>*range_stub = make_range_from_width(64);
 	svector<PWire*>*tmp = pform_make_task_ports(@1, $1, IVL_VT_LOGIC, false,
 						    range_stub, $3);
 	$$ = tmp;
diff --git a/pform.cc b/pform.cc
index 2a8653c60..d500bf7ff 100644
--- a/pform.cc
+++ b/pform.cc
@@ -1480,16 +1480,15 @@ void pform_make_udp(perm_string name, bool synchronous_flag,
       delete init_expr;
 }
 
-static void ranges_from_list(list<PWire::range_t>&rlist, const list<PExpr*>*range)
+static void ranges_from_list(list<PWire::range_t>&rlist,
+			     const list<index_component_t>*range)
 {
-	// There must be an even number of expressions in the
-	// range. The parser will assure that for us.
-      assert(range->size()%2 == 0);
-      list<PExpr*>::const_iterator rcur = range->begin();
-      while (rcur != range->end()) {
+	// Convert a list of index_component_t to PWire::range_t.
+      for (list<index_component_t>::const_iterator rcur = range->begin()
+		 ; rcur != range->end() ; ++rcur) {
 	    PWire::range_t rng;
-	    rng.msb = *rcur; ++rcur;
-	    rng.lsb = *rcur; ++rcur;
+	    rng.msb = rcur->msb;
+	    rng.lsb = rcur->lsb;
 	    rlist.push_back(rng);
       }
 }
@@ -1500,7 +1499,7 @@ static void ranges_from_list(list<PWire::range_t>&rlist, const list<PExpr*>*rang
  * and the name that I receive only has the tail component.
  */
 static void pform_set_net_range(perm_string name,
-				const list<PExpr*>*range,
+				const list<index_component_t>*range,
 				bool signed_flag,
 				ivl_variable_type_t dt,
 				PWSRType rt)
@@ -1528,12 +1527,10 @@ static void pform_set_net_range(perm_string name,
 }
 
 static void pform_set_net_range(list<perm_string>*names,
-				list<PExpr*>*range,
+				list<index_component_t>*range,
 				bool signed_flag,
 				ivl_variable_type_t dt)
 {
-      assert((range == 0) || (range->size()%2 == 0));
-
       for (list<perm_string>::iterator cur = names->begin()
 		 ; cur != names->end() ; ++ cur ) {
 	    perm_string txt = *cur;
@@ -1601,8 +1598,8 @@ static void pform_makegate(PGBuiltin::Type type,
 
       perm_string dev_name = lex_strings.make(info.name);
       PGBuiltin*cur = new PGBuiltin(type, dev_name, info.parms, delay);
-      if (info.range[0])
-	    cur->set_range(info.range[0], info.range[1]);
+      if (info.range.msb)
+	    cur->set_range(info.range.msb, info.range.lsb);
 
 	// The pform_makegates() that calls me will take care of
 	// deleting the attr pointer, so tell the
@@ -1741,7 +1738,7 @@ void pform_make_modgates(perm_string type,
 	    if (cur.parms_by_name) {
 		  pform_make_modgate(type, cur_name, overrides,
 				     cur.parms_by_name,
-				     cur.range[0], cur.range[1],
+				     cur.range.msb, cur.range.lsb,
 				     cur.file, cur.lineno);
 
 	    } else if (cur.parms) {
@@ -1755,14 +1752,14 @@ void pform_make_modgates(perm_string type,
 		  }
 		  pform_make_modgate(type, cur_name, overrides,
 				     cur.parms,
-				     cur.range[0], cur.range[1],
+				     cur.range.msb, cur.range.lsb,
 				     cur.file, cur.lineno);
 
 	    } else {
 		  list<PExpr*>*wires = new list<PExpr*>;
 		  pform_make_modgate(type, cur_name, overrides,
 				     wires,
-				     cur.range[0], cur.range[1],
+				     cur.range.msb, cur.range.lsb,
 				     cur.file, cur.lineno);
 	    }
       }
@@ -1875,7 +1872,7 @@ void pform_module_define_port(const struct vlltype&li,
 			      NetNet::Type type,
 			      ivl_variable_type_t data_type,
 			      bool signed_flag,
-			      list<PExpr*>*range,
+			      list<index_component_t>*range,
 			      list<named_pexpr_t>*attr)
 {
       PWire*cur = pform_get_wire_in_scope(name);
@@ -2011,7 +2008,7 @@ void pform_makewire(const vlltype&li, perm_string name,
  * pform_makewire above.
  */
 void pform_makewire(const vlltype&li,
-		    list<PExpr*>*range,
+		    list<index_component_t>*range,
 		    bool signed_flag,
 		    list<perm_string>*names,
 		    NetNet::Type type,
@@ -2038,7 +2035,7 @@ void pform_makewire(const vlltype&li,
  * This form makes nets with delays and continuous assignments.
  */
 void pform_makewire(const vlltype&li,
-		    list<PExpr*>*range,
+		    list<index_component_t>*range,
 		    bool signed_flag,
 		    list<PExpr*>*delay,
 		    str_pair_t str,
@@ -2149,7 +2146,7 @@ svector<PWire*>*pform_make_task_ports(const struct vlltype&loc,
 				      NetNet::PortType pt,
 				      ivl_variable_type_t vtype,
 				      bool signed_flag,
-				      list<PExpr*>*range,
+				      list<index_component_t>*range,
 				      list<perm_string>*names,
 				      bool isint)
 {
@@ -2198,7 +2195,7 @@ svector<PWire*>*pform_make_task_ports(const struct vlltype&loc,
 				      list<perm_string>*names)
 {
       if (atom2_type_t*atype = dynamic_cast<atom2_type_t*> (vtype)) {
-	    list<PExpr*>*range_tmp = make_range_from_width(atype->type_code);
+	    list<index_component_t>*range_tmp = make_range_from_width(atype->type_code);
 	    return pform_make_task_ports(loc, pt, IVL_VT_BOOL,
 					 atype->signed_flag,
 					 range_tmp, names);
@@ -2211,7 +2208,7 @@ svector<PWire*>*pform_make_task_ports(const struct vlltype&loc,
 					 names);
       }
 
-      if (real_type_t*real_type = dynamic_cast<real_type_t*> (vtype)) {
+      if (/*real_type_t*real_type = */ dynamic_cast<real_type_t*> (vtype)) {
 	    return pform_make_task_ports(loc, pt, IVL_VT_REAL,
 					 true, 0, names);
       }
@@ -2325,7 +2322,7 @@ LexicalScope::range_t* pform_parameter_value_range(bool exclude_flag,
 
 void pform_set_parameter(const struct vlltype&loc,
 			 perm_string name, ivl_variable_type_t type,
-			 bool signed_flag, list<PExpr*>*range, PExpr*expr,
+			 bool signed_flag, list<index_component_t>*range, PExpr*expr,
 			 LexicalScope::range_t*value_range)
 {
       LexicalScope*scope = lexical_scope;
@@ -2360,11 +2357,12 @@ void pform_set_parameter(const struct vlltype&loc,
 
       parm.type = type;
       if (range) {
-	    assert(range->size() == 2);
-	    assert(range->front());
-	    assert(range->back());
-	    parm.msb = range->front();
-	    parm.lsb = range->back();
+	    assert(range->size() == 1);
+	    index_component_t index = range->front();
+	    assert(index.msb);
+	    assert(index.lsb);
+	    parm.msb = index.msb;
+	    parm.lsb = index.lsb;
       } else {
 	    parm.msb = 0;
 	    parm.lsb = 0;
@@ -2378,7 +2376,7 @@ void pform_set_parameter(const struct vlltype&loc,
 
 void pform_set_localparam(const struct vlltype&loc,
 			  perm_string name, ivl_variable_type_t type,
-			  bool signed_flag, list<PExpr*>*range, PExpr*expr)
+			  bool signed_flag, list<index_component_t>*range, PExpr*expr)
 {
       LexicalScope*scope = lexical_scope;
 
@@ -2408,11 +2406,12 @@ void pform_set_localparam(const struct vlltype&loc,
 
       parm.type = type;
       if (range) {
-	    assert(range->size() == 2);
-	    assert(range->front());
-	    assert(range->back());
-	    parm.msb = range->front();
-	    parm.lsb = range->back();
+	    assert(range->size() == 1);
+	    index_component_t index = range->front();
+	    assert(index.msb);
+	    assert(index.lsb);
+	    parm.msb = index.msb;
+	    parm.lsb = index.lsb;
       } else {
 	    parm.msb  = 0;
 	    parm.lsb  = 0;
@@ -2511,7 +2510,7 @@ extern void pform_module_specify_path(PSpecPath*obj)
 
 void pform_set_port_type(const struct vlltype&li,
 			 list<perm_string>*names,
-			 list<PExpr*>*range,
+			 list<index_component_t>*range,
 			 bool signed_flag,
 			 NetNet::PortType pt)
 {
@@ -2627,7 +2626,7 @@ void pform_set_data_type(const struct vlltype&li, data_type_t*data_type, list<pe
 	    return;
       }
 
-      if (real_type_t*real_type = dynamic_cast<real_type_t*> (data_type)) {
+      if (/*real_type_t*real_type =*/ dynamic_cast<real_type_t*> (data_type)) {
 	    pform_set_net_range(names, 0, true, IVL_VT_REAL);
 	    return;
       }
@@ -2645,7 +2644,7 @@ static void pform_set_enum(const struct vlltype&li, enum_type_t*enum_type,
       cur->set_signed(enum_type->signed_flag);
 
       assert(enum_type->range.get() != 0);
-      assert(enum_type->range->size() == 2);
+      assert(enum_type->range->size() == 1);
       list<PWire::range_t>rlist;
       ranges_from_list(rlist, enum_type->range.get());
       cur->set_range(rlist, SR_NET);
@@ -2659,7 +2658,7 @@ void pform_set_enum(const struct vlltype&li, enum_type_t*enum_type, list<perm_st
       assert(enum_type->base_type==IVL_VT_LOGIC || enum_type->base_type==IVL_VT_BOOL);
 
       assert(enum_type->range.get() != 0);
-      assert(enum_type->range->size() == 2);
+      assert(enum_type->range->size() == 1);
 
 	// Add the file and line information to the enumeration type.
       FILE_NAME(&(enum_type->li), li);
diff --git a/pform.h b/pform.h
index 0e2613715..85039e7df 100644
--- a/pform.h
+++ b/pform.h
@@ -101,24 +101,22 @@ struct net_decl_assign_t {
 
 /* The lgate is gate instantiation information. */
 struct lgate {
-      lgate(int =0)
+      inline lgate(int =0)
       : parms(0), parms_by_name(0), file(NULL), lineno(0)
-      { range[0] = 0;
-        range[1] = 0;
-      }
+      { }
 
       string name;
       list<PExpr*>*parms;
       list<named_pexpr_t>*parms_by_name;
 
-      PExpr*range[2];
+      index_component_t range;
 
       const char* file;
       unsigned lineno;
 };
 
-extern std::list<PExpr*>* make_range_from_width(uint64_t wid);
-extern list<PExpr*>* copy_range(list<PExpr*>* orig);
+extern std::list<index_component_t>* make_range_from_width(uint64_t wid);
+extern std::list<index_component_t>* copy_range(std::list<index_component_t>* orig);
 
   /* Use this function to transform the parted form of the attribute
      list to the attribute map that is used later. */
@@ -161,7 +159,7 @@ extern void pform_module_define_port(const struct vlltype&li,
 				     NetNet::Type type,
 				     ivl_variable_type_t data_type,
 				     bool signed_flag,
-				     list<PExpr*>*range,
+				     list<index_component_t>*range,
 				     list<named_pexpr_t>*attr);
 
 extern Module::port_t* pform_module_port_reference(perm_string name,
@@ -241,7 +239,7 @@ extern void pform_makewire(const struct vlltype&li, perm_string name,
 
 /* This form handles simple declarations */
 extern void pform_makewire(const struct vlltype&li,
-			   list<PExpr*>*range,
+			   list<index_component_t>*range,
 			   bool signed_flag,
 			   list<perm_string>*names,
 			   NetNet::Type type,
@@ -258,7 +256,7 @@ extern void pform_makewire(const struct vlltype&li,
 
 /* This form handles assignment declarations. */
 extern void pform_makewire(const struct vlltype&li,
-			   list<PExpr*>*range,
+			   list<index_component_t>*range,
 			   bool signed_flag,
 			   list<PExpr*>*delay,
 			   str_pair_t str,
@@ -281,7 +279,7 @@ extern void pform_make_reginit(const struct vlltype&li,
      it. The second form takes a single name. */
 extern void pform_set_port_type(const struct vlltype&li,
 				list<perm_string>*names,
-				list<PExpr*>*range,
+				list<index_component_t>*range,
 				bool signed_flag,
 				NetNet::PortType);
 extern void pform_set_port_type(perm_string nm, NetNet::PortType pt,
@@ -316,13 +314,13 @@ extern void pform_set_parameter(const struct vlltype&loc,
 				perm_string name,
 				ivl_variable_type_t type,
 				bool signed_flag,
-				list<PExpr*>*range,
+				list<index_component_t>*range,
 				PExpr*expr, LexicalScope::range_t*value_range);
 extern void pform_set_localparam(const struct vlltype&loc,
 				 perm_string name,
 				 ivl_variable_type_t type,
 				 bool signed_flag,
-				 list<PExpr*>*range,
+				 list<index_component_t>*range,
 				 PExpr*expr);
 extern void pform_set_defparam(const pform_name_t&name, PExpr*expr);
 
@@ -386,7 +384,7 @@ extern svector<PWire*>*pform_make_task_ports(const struct vlltype&loc,
 					     NetNet::PortType pt,
 					     ivl_variable_type_t vtype,
 					     bool signed_flag,
-					     list<PExpr*>*range,
+					     list<index_component_t>*range,
 					     list<perm_string>*names,
 					     bool isint = false);
 
diff --git a/pform_types.h b/pform_types.h
index 8ec228eaa..ab700cadc 100644
--- a/pform_types.h
+++ b/pform_types.h
@@ -1,7 +1,7 @@
 #ifndef __pform_types_H
 #define __pform_types_H
 /*
- * Copyright (c) 2007-2011 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2007-2012 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -84,14 +84,14 @@ struct data_type_t : public LineInfo {
 struct enum_type_t : public data_type_t {
       ivl_variable_type_t base_type;
       bool signed_flag;
-      std::auto_ptr< list<PExpr*> > range;
+      std::auto_ptr< list<index_component_t> > range;
       std::auto_ptr< list<named_pexpr_t> > names;
       LineInfo li;
 };
 
 struct struct_member_t : public LineInfo {
       ivl_variable_type_t type;
-      std::auto_ptr< list<PExpr*> > range;
+      std::auto_ptr< list<index_component_t> > range;
       std::auto_ptr< list<decl_assignment_t*> > names;
 };
 
@@ -108,11 +108,12 @@ struct atom2_type_t : public data_type_t {
 };
 
 struct vector_type_t : public data_type_t {
-      inline explicit vector_type_t(ivl_variable_type_t bt, bool sf, list<PExpr*>*pd)
+      inline explicit vector_type_t(ivl_variable_type_t bt, bool sf,
+				    std::list<index_component_t>*pd)
       : base_type(bt), signed_flag(sf), pdims(pd) { }
       ivl_variable_type_t base_type;
       bool signed_flag;
-      std::auto_ptr< list<PExpr*> > pdims;
+      std::auto_ptr< list<index_component_t> > pdims;
 };
 
 struct real_type_t : public data_type_t {