Index: trunk/src/libcschem/Makefile.in
===================================================================
--- trunk/src/libcschem/Makefile.in	(revision 685)
+++ trunk/src/libcschem/Makefile.in	(revision 686)
@@ -4,6 +4,7 @@
 include {template/cc.tmpasm}
 
 put /local/csch/OBJS [@
+ abstract.o
  attrib.o
  buildin.o
  compat.o
Index: trunk/src/libcschem/abstract.c
===================================================================
--- trunk/src/libcschem/abstract.c	(nonexistent)
+++ trunk/src/libcschem/abstract.c	(revision 686)
@@ -0,0 +1,55 @@
+/*
+ *                            COPYRIGHT
+ *
+ *  cschem - modular/flexible schematics editor - libcschem (core library)
+ *  Copyright (C) 2019 Tibor 'Igor2' Palinkas
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.*
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *  Contact:
+ *    Project page: http://repo.hu/projects/cschem
+ *    lead developer: email to cschem (at) igor2.repo.hu
+ *    mailing list: cschem (at) list.repo.hu (send "subscribe")
+ */
+
+#include "config.h"
+
+#include <genht/htip.h>
+#include <genht/htsp.h>
+#include <genht/hash.h>
+
+#include "abstract.h"
+#include "compat.h"
+
+void csch_abstract_init(csch_abstract_t *abs)
+{
+	memset(abs, 0, sizeof(csch_abstract_t));
+	htsp_init(&abs->nets, strhash, strkeyeq);
+}
+
+csch_anet_t *csch_anet_get(csch_abstract_t *abs, const char *netname, int alloc)
+{
+	csch_anet_t *net;
+
+	net = htsp_get(&abs->nets, netname);
+	if ((net != NULL) || (!alloc))
+		return net;
+
+	net = calloc(sizeof(csch_anet_t), 1);
+	net->netname = csch_strdup(netname);
+	htsp_set(&abs->nets, net->netname, net);
+	return net;
+}
+
Index: trunk/src/libcschem/abstract.h
===================================================================
--- trunk/src/libcschem/abstract.h	(revision 685)
+++ trunk/src/libcschem/abstract.h	(revision 686)
@@ -24,6 +24,9 @@
  *    mailing list: cschem (at) list.repo.hu (send "subscribe")
  */
 
+#ifndef CSCH_ABSTRACT_H
+#define CSCH_ABSTRACT_H
+
 #include <genht/htip.h>
 #include <genht/htsp.h>
 
@@ -115,6 +118,10 @@
 } csch_ahub_t;
 
 
+/*** abs ***/
+void csch_abstract_init(csch_abstract_t *abs);
+
 /*** net ***/
 csch_anet_t *csch_anet_get(csch_abstract_t *abs, const char *netname, int alloc);
 
+#endif
Index: trunk/src/libcschem/compile.h
===================================================================
--- trunk/src/libcschem/compile.h	(revision 685)
+++ trunk/src/libcschem/compile.h	(revision 686)
@@ -23,3 +23,13 @@
  *    lead developer: email to cschem (at) igor2.repo.hu
  *    mailing list: cschem (at) list.repo.hu (send "subscribe")
  */
+
+#ifndef CSCH_COMPILE_H
+#define CSCH_COMPILE_H
+
+#include <libcschem/abstract.h>
+#include <libcschem/concrete.h>
+
+int csch_compile_sheet(csch_abstract_t *dst, const csch_sheet_t *src);
+
+#endif