diff --git a/.gitignore b/.gitignore
index 21e8b33cb..f27cdac9d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -43,6 +43,13 @@ dep
 
 /ivlpp/lexor.c
 
+/vhdlpp/lexor.cc
+/vhdlpp/lexor_keyword.cc
+/vhdlpp/parse.cc
+/vhdlpp/parse.h
+/vhdlpp/vhdlpp_config.h
+/vhdlpp/vhdlpp
+
 /lexor.cc
 /lexor_keyword.cc
 /parse.cc
diff --git a/Makefile.in b/Makefile.in
index fcad472a3..48e28d1b8 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -38,7 +38,7 @@ exec_prefix = @exec_prefix@
 srcdir = @srcdir@
 datarootdir = @datarootdir@
 
-SUBDIRS = ivlpp vvp vpi libveriuser cadpli tgt-null tgt-stub tgt-vvp \
+SUBDIRS = ivlpp vhdlpp vvp vpi libveriuser cadpli tgt-null tgt-stub tgt-vvp \
           tgt-vhdl tgt-vlog95 driver
 # Only run distclean for these directories.
 NOTUSED = tgt-fpga tgt-pal tgt-verilog
@@ -80,9 +80,9 @@ PS2PDF = @PS2PDF@
 GIT = @GIT@
 
 ifeq (@srcdir@,.)
-INCLUDE_PATH = -I.
+INCLUDE_PATH = -I. -Ilibmisc
 else
-INCLUDE_PATH = -I. -I$(srcdir)
+INCLUDE_PATH = -I. -Ilibmisc -I$(srcdir) -I$(srcdir)/libmisc
 endif
 
 CPPFLAGS = @DEFS@ $(INCLUDE_PATH) @CPPFLAGS@
@@ -91,6 +91,9 @@ CXXFLAGS = @WARNING_FLAGS@ @WARNING_FLAGS_CXX@ @CXXFLAGS@
 PICFLAGS = @PICFLAG@
 LDFLAGS = @rdynamic@ @LDFLAGS@
 
+# Source files in the libmisc directory
+M = LineInfo.o StringHeap.o
+
 TT = t-dll.o t-dll-api.o t-dll-expr.o t-dll-proc.o t-dll-analog.o
 FF = cprop.o nodangle.o synth.o synth2.o syn-rules.o
 
@@ -104,9 +107,9 @@ O = main.o async.o design_dump.o discipline.o dup_expr.o elaborate.o \
     net_udp.o pad_to_width.o parse.o parse_misc.o pform.o pform_analog.o \
     pform_disciplines.o pform_dump.o pform_types.o set_width.o \
     symbol_search.o sync.o sys_funcs.o verinum.o verireal.o target.o \
-    Attrib.o HName.o LineInfo.o Module.o PDelays.o PEvent.o PExpr.o PGate.o \
+    Attrib.o HName.o Module.o PDelays.o PEvent.o PExpr.o PGate.o \
     PGenerate.o PScope.o PSpec.o PTask.o PUdp.o PFunction.o PWire.o \
-    Statement.o AStatement.o StringHeap.o $(FF) $(TT)
+    Statement.o AStatement.o $M $(FF) $(TT)
 
 all: dep config.h _pli_types.h version_tag.h ivl@EXEEXT@ version.exe iverilog-vpi.man
 	$(foreach dir,$(SUBDIRS),$(MAKE) -C $(dir) $@ && ) true
@@ -197,7 +200,7 @@ ifeq (@WIN32@,yes)
 # The first step makes an ivl.exe that dlltool can use to make an
 # export and import library, and the last link makes a, ivl.exe
 # that really exports the things that the import library imports.
-ivl@EXEEXT@: $O $(srcdir)/ivl.def
+ivl@EXEEXT@: $O  $(srcdir)/ivl.def
 	$(CXX) -o ivl@EXEEXT@ $O $(dllib) @EXTRALIBS@
 	dlltool --dllname ivl@EXEEXT@ --def $(srcdir)/ivl.def \
 		--output-lib libivl.a --output-exp ivl.exp
@@ -229,6 +232,10 @@ version.exe: $(srcdir)/version.c $(srcdir)/version_base.h version_tag.h
 	$(CXX) $(CPPFLAGS) $(CXXFLAGS) @DEPENDENCY_FLAG@ -c $< -o $*.o
 	mv $*.d dep/$*.d
 
+%.o: $(srcdir)/libmisc/%.cc
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) @DEPENDENCY_FLAG@ -c $< -o $*.o
+	mv $*.d dep/$*.d
+
 # Here are some explicit dependencies needed to get things going.
 main.o: main.cc version_tag.h
 
diff --git a/configure.in b/configure.in
index edbcf90c9..d3ca2fdc9 100644
--- a/configure.in
+++ b/configure.in
@@ -2,6 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 AC_INIT(netlist.h)
 AC_CONFIG_HEADER(config.h)
 AC_CONFIG_HEADER(_pli_types.h)
+AC_CONFIG_HEADER(vhdlpp/vhdlpp_config.h)
 AC_CONFIG_HEADER(vvp/config.h)
 AC_CONFIG_HEADER(vpi/vpi_config.h)
 AC_CONFIG_HEADER(libveriuser/config.h)
@@ -295,4 +296,4 @@ AC_MSG_RESULT(ok)
 
 # XXX disable tgt-fpga for the moment
 
-AC_OUTPUT(Makefile ivlpp/Makefile vvp/Makefile vpi/Makefile driver/Makefile driver-vpi/Makefile cadpli/Makefile libveriuser/Makefile tgt-null/Makefile tgt-stub/Makefile tgt-vvp/Makefile tgt-vhdl/Makefile tgt-fpga/Makefile tgt-verilog/Makefile tgt-pal/Makefile tgt-vlog95/Makefile)
+AC_OUTPUT(Makefile ivlpp/Makefile vhdlpp/Makefile vvp/Makefile vpi/Makefile driver/Makefile driver-vpi/Makefile cadpli/Makefile libveriuser/Makefile tgt-null/Makefile tgt-stub/Makefile tgt-vvp/Makefile tgt-vhdl/Makefile tgt-fpga/Makefile tgt-verilog/Makefile tgt-pal/Makefile tgt-vlog95/Makefile)
diff --git a/driver/main.c b/driver/main.c
index 677f3eebe..b63f46616 100644
--- a/driver/main.c
+++ b/driver/main.c
@@ -106,7 +106,8 @@ const char sep = '/';
 extern void cfreset(FILE*fd, const char*path);
 
 const char*base = 0;
-const char*pbase = 0;
+const char*ivlpp_dir = 0;
+const char*vhdlpp_dir= 0;
 const char*mtm  = 0;
 const char*opath = "a.out";
 const char*npath = 0;
@@ -304,7 +305,7 @@ static int t_version_only(void)
       free(source_path);
 
       fflush(0);
-      snprintf(tmp, sizeof tmp, "%s%civlpp -V", pbase, sep);
+      snprintf(tmp, sizeof tmp, "%s%civlpp -V", ivlpp_dir, sep);
       rc = system(tmp);
       if (rc != 0) {
 	    fprintf(stderr, "Unable to get version from \"%s\"\n", tmp);
@@ -333,7 +334,7 @@ static int t_version_only(void)
 static void build_preprocess_command(int e_flag)
 {
       snprintf(tmp, sizeof tmp, "%s%civlpp %s%s -F\"%s\" -f\"%s\" -p\"%s\" ",
-	       pbase, sep, verbose_flag?" -v":"",
+	       ivlpp_dir, sep, verbose_flag?" -v":"",
 	       e_flag?"":" -L", defines_path, source_path,
 	       compiled_defines_path);
 }
@@ -875,14 +876,20 @@ int main(int argc, char **argv)
 
 	    switch (opt) {
 		case 'B':
-		    /* Undocumented feature: The preprocessor itself
-		       may be located at a different location. If the
-		       base starts with a 'P', set this special base
-		       instead of the main base. */
-		  if (optarg[0] == 'P') {
-			pbase = optarg+1;
-		  } else {
+		    /* The individual components can be located by a
+		       single base, or by individual bases. The first
+		       character of the path indicates which path the
+		       user is specifying. */
+		  switch (optarg[0]) {
+		      case 'P': /* Path for the ivlpp preprocessor */
+			ivlpp_dir = optarg+1;
+			break;
+		      case 'V': /* Path for the vhdlpp VHDL processor */
+			vhdlpp_dir = optarg+1;
+			break;
+		      default: /* Otherwise, this is a default base. */
 			base=optarg;
+			break;
 		  }
 		  break;
 		case 'c':
@@ -995,8 +1002,10 @@ int main(int argc, char **argv)
 	    }
       }
 
-      if (pbase == 0)
-	    pbase = base;
+      if (ivlpp_dir == 0)
+	    ivlpp_dir = base;
+      if (vhdlpp_dir == 0)
+	    vhdlpp_dir = base;
 
       if (version_flag || verbose_flag) {
 	    printf("Icarus Verilog version " VERSION " (" VERSION_TAG ")\n\n");
@@ -1017,6 +1026,8 @@ int main(int argc, char **argv)
       snprintf(iconfig_common_path, sizeof iconfig_common_path, "%s%c%s%s.conf",
 	      base, sep, targ, synth_flag? "-s" : "");
 
+      fprintf(defines_file, "vhdlpp:%s%cvhdlpp\n", vhdlpp_dir, sep);
+
 	/* Write values to the iconfig file. */
       fprintf(iconfig_file, "basedir:%s\n", base);
 
@@ -1143,7 +1154,7 @@ int main(int argc, char **argv)
 	   single file. This may be used to preprocess library
 	   files. */
       fprintf(iconfig_file, "ivlpp:%s%civlpp -L -F\"%s\" -P\"%s\"\n",
-	      pbase, sep, defines_path, compiled_defines_path);
+	      ivlpp_dir, sep, defines_path, compiled_defines_path);
 
 	/* Done writing to the iconfig file. Close it now. */
       fclose(iconfig_file);
diff --git a/ivlpp/globals.h b/ivlpp/globals.h
index c30991b06..236659684 100644
--- a/ivlpp/globals.h
+++ b/ivlpp/globals.h
@@ -33,6 +33,8 @@ extern void dump_precompiled_defines(FILE*out);
    an include directive in encountered. */
 extern char**include_dir;
 extern unsigned include_cnt;
+/* Program to use for VHDL processing. */
+extern char*vhdlpp_path;
 
 extern int relative_include;
 
diff --git a/ivlpp/ivlpp.txt b/ivlpp/ivlpp.txt
index 84ca39781..d8b7d7506 100644
--- a/ivlpp/ivlpp.txt
+++ b/ivlpp/ivlpp.txt
@@ -42,6 +42,15 @@ valid options include:
 	    This option does *not* override existing `define
 	    directives in the source file.
 
+	-F <path>
+	    Read ivlpp options from a FLAGS FILE. This is not the same
+	    as a file list. This file contains flags, not source
+	    files. There may be multiple flags files.
+
+	-f <path>
+	    Read ivlpp input files from a file list. There can be no
+	    more then one file list.
+
 	-I <dir>
 	    Add a directory to the include path. Normally, only "." is
 	    in the search path. The -I flag causes other directories
@@ -59,8 +68,42 @@ valid options include:
 	    output.
 
 	-v
-	    Print version and copyright information
+	    Print version and copyright information before processing
+	    input files.
 
+	-V
+	    Print version and copyright information, then exit WITHOUT
+	    processing any input files.
+
+FLAGS FILE
+
+A flags file contains flags for use by ivlpp. This is a convenient way
+for programs to pass complex sets of flags to the ivlpp program.
+
+Blank lines and lines that start with "#" are ignored. The latter can
+be used as comment lines. All other lines are flag lines. Leading and
+trailing white space are removed before the lines are interpreted.
+
+Other lines have the simple format:
+
+  <key>:<value>
+
+The colon character separates a key from the value. The supported
+keys, with their corresponding values, are:
+
+   D:name=<value>
+      This is exactly the same as the "-Dname=<value>" described above.
+
+   I:<dir>
+      This is exctly the same as "-I<dir>".
+
+   relative include:<flag>
+      The <flag> can be "true" or "false". This enables "relative
+      includes" nesting behavior.
+
+   vhdlpp:<path>
+      Give the path to the vhdlpp program. This program is used to
+      process VHDL input files.
 
 LOCATING INCLUDED FILES
 
diff --git a/ivlpp/lexor.lex b/ivlpp/lexor.lex
index 335c92920..313011ada 100644
--- a/ivlpp/lexor.lex
+++ b/ivlpp/lexor.lex
@@ -59,6 +59,7 @@ struct include_stack_t
 
     /* If the current input is from a file, this member is set. */
     FILE* file;
+    int (*file_close)(FILE*);
 
     /* If we are reparsing a macro expansion, file is 0 and this
      * member points to the string in progress
@@ -1614,8 +1615,10 @@ static void do_include()
 {
     /* standby is defined by include_filename() */
     if (standby->path[0] == '/') {
-        if ((standby->file = fopen(standby->path, "r")))
+	if ((standby->file = fopen(standby->path, "r"))) {
+	    standby->file_close = fclose;
             goto code_that_switches_buffers;
+	}
     } else {
         unsigned idx, start = 1;
         char path[4096];
@@ -1644,6 +1647,7 @@ static void do_include()
             sprintf(path, "%s/%s", include_dir[idx], standby->path);
 
             if ((standby->file = fopen(path, "r"))) {
+		standby->file_close = fclose;
                 /* Free the original path before we overwrite it. */
                 free(standby->path);
                 standby->path = strdup(path);
@@ -1750,6 +1754,58 @@ static void lexor_done()
     }
 }
 
+/*
+ * Use this function to open a source file that is to be
+ * processed. Do NOT use this function for opening include files,
+ * instead only use this file for opening base source files.
+ */
+static void open_input_file(struct include_stack_t*isp)
+{
+      char*cp;
+      int is_vhdl = 0;
+
+      isp->file = 0;
+
+	/* look for a suffix for the input file. If the suffix
+	   indicates that this is a VHDL source file, then invoke
+	   vhdlpp to get a data stream. */
+      cp = strrchr(isp->path, '.');
+      if (cp && vhdlpp_path) {
+	    if (strcmp(cp, ".vhd") == 0) {
+		  is_vhdl = 1;
+	    } else if (strcmp(cp, ".vhdl") == 0) {
+		  is_vhdl = 1;
+	    }
+      }
+
+      if (is_vhdl == 0) {
+	    isp->file = fopen(isp->path, "r");
+	    isp->file_close = fclose;
+	    return;
+      }
+
+      size_t cmdlen = strlen(vhdlpp_path);
+      cmdlen += strlen(isp->path);
+      cmdlen += 32;
+
+      char*cmd = malloc(cmdlen);
+      snprintf(cmd, cmdlen, "%s %s", vhdlpp_path, isp->path);
+
+      isp->file = popen(cmd, "r");
+      isp->file_close = pclose;
+
+      free(cmd);
+      return;
+}
+
+/*
+ * The load_next_input() function is called by the lexical analyzer
+ * when the current file runs out. When the EOF of the current input
+ * file is matched, this function figures out if this is the end of an
+ * included file (in which case the including file is resumed) or the
+ * end of a base file, in which case the next base source file is
+ * opened.
+ */
 static int load_next_input()
 {
     int line_mask_flag = 0;
@@ -1773,7 +1829,8 @@ static int load_next_input()
     if (isp->file)
     {
         free(isp->path);
-        fclose(isp->file);
+	assert(isp->file_close);
+        isp->file_close(isp->file);
     }
     else
     {
@@ -1813,7 +1870,7 @@ static int load_next_input()
 
         istack->next = 0;
         istack->lineno = 0;
-        istack->file = fopen(istack->path, "r");
+        open_input_file(istack);
 
         if (istack->file == 0)
         {
@@ -1966,7 +2023,7 @@ void reset_lexor(FILE* out, char* paths[])
     isp = malloc(sizeof(struct include_stack_t));
     isp->next = 0;
     isp->path = strdup(paths[0]);
-    isp->file = fopen(paths[0], "r");
+    open_input_file(isp);
     isp->str = 0;
     isp->lineno = 0;
     isp->stringify_flag = 0;
diff --git a/ivlpp/main.c b/ivlpp/main.c
index 3b8d1857d..8a92da3e1 100644
--- a/ivlpp/main.c
+++ b/ivlpp/main.c
@@ -57,7 +57,8 @@ extern const char*optarg;
 char *dep_path = NULL;
 /* Dependency file output mode */
 char dep_mode = 'a';
-
+/* Path to vhdlpp */
+char *vhdlpp_path = 0;
 
 /*
  * Keep in source_list an array of pointers to file names. The array
@@ -166,6 +167,13 @@ static int flist_read_flags(const char*path)
 			relative_include = 0;
 		  }
 
+	    } else if (strcmp(cp,"vhdlpp") == 0) {
+		  if (vhdlpp_path) {
+			fprintf(stderr, "Ignore multiple vhdlpp flags\n");
+		  } else {
+			vhdlpp_path = strdup(arg);
+		  }
+
 	    } else {
 		  fprintf(stderr, "%s: Invalid keyword %s\n", path, cp);
 	    }
diff --git a/LineInfo.cc b/libmisc/LineInfo.cc
similarity index 98%
rename from LineInfo.cc
rename to libmisc/LineInfo.cc
index 5b43d95fd..047cbf4bb 100644
--- a/LineInfo.cc
+++ b/libmisc/LineInfo.cc
@@ -17,11 +17,11 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 
-# include "config.h"
-
 # include  "LineInfo.h"
 # include  <sstream>
 
+using namespace std;
+
 LineInfo::LineInfo()
 : lineno_(0)
 {
diff --git a/LineInfo.h b/libmisc/LineInfo.h
similarity index 100%
rename from LineInfo.h
rename to libmisc/LineInfo.h
diff --git a/StringHeap.cc b/libmisc/StringHeap.cc
similarity index 99%
rename from StringHeap.cc
rename to libmisc/StringHeap.cc
index 4ee081a07..8b8b0cde1 100644
--- a/StringHeap.cc
+++ b/libmisc/StringHeap.cc
@@ -21,7 +21,6 @@
 # include  <cstdlib>
 # include  <cstring>
 # include  <cassert>
-# include  "ivl_alloc.h"
 
 #ifdef CHECK_WITH_VALGRIND
 static char **string_pool = NULL;
diff --git a/StringHeap.h b/libmisc/StringHeap.h
similarity index 99%
rename from StringHeap.h
rename to libmisc/StringHeap.h
index 8457845a8..27ed1a3f4 100644
--- a/StringHeap.h
+++ b/libmisc/StringHeap.h
@@ -19,7 +19,6 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 
-# include  "config.h"
 # include  <string>
 
 using namespace std;
diff --git a/vhdlpp/Makefile.in b/vhdlpp/Makefile.in
new file mode 100644
index 000000000..01cd46da6
--- /dev/null
+++ b/vhdlpp/Makefile.in
@@ -0,0 +1,118 @@
+#
+#    This source code is free software; you can redistribute it
+#    and/or modify it in source code form under the terms of the GNU
+#    Library General Public License as published by the Free Software
+#    Foundation; either version 2 of the License, or (at your option)
+#    any later version.
+#
+#    This program 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 Library General Public License for more details.
+#
+#    You should have received a copy of the GNU Library General Public
+#    License along with this program; if not, write to the Free
+#    Software Foundation, Inc.,
+#    59 Temple Place - Suite 330
+#    Boston, MA 02111-1307, USA
+#
+SHELL = /bin/sh
+
+suffix = @install_suffix@
+
+prefix = @prefix@
+exec_prefix = @exec_prefix@
+srcdir = @srcdir@
+
+VPATH = $(srcdir)
+
+bindir = @bindir@
+libdir = @libdir@
+includedir = $(prefix)/include
+
+CC = @CC@
+CXX = @CXX@
+INSTALL = @INSTALL@
+INSTALL_SCRIPT = @INSTALL_SCRIPT@
+INSTALL_PROGRAM = @INSTALL_PROGRAM@
+INSTALL_DATA = @INSTALL_DATA@
+LEX = @LEX@
+YACC = @YACC@
+
+ifeq (.,.)
+INCLUDE_PATH = -I. -I.. -I../libmisc
+else
+INCLUDE_PATH = -I. -I.. -I$(srcdir) -I$(srcdir)/../libmisc
+endif
+
+CPPFLAGS = $(INCLUDE_PATH) @CPPFLAGS@ @DEFS@
+CFLAGS = @WARNING_FLAGS@ @CFLAGS@
+CXXFLAGS = @WARNING_FLAGS@ @WARNING_FLAGS_CXX@ @CXXFLAGS@
+LDFLAGS = @LDFLAGS@
+LIBS = @LIBS@ @EXTRALIBS@
+
+M = StringHeap.o LineInfo.o
+
+O = main.o compiler.o entity.o entity_elaborate.o \
+    lexor.o lexor_keyword.o parse.o $M
+
+all: dep vhdlpp@EXEEXT@
+
+clean:
+	rm -f *.o *~
+	rm -rf dep vhdlpp@EXEEXT@
+
+distclean: clean
+	rm -f Makefile config.log
+	rm -f stamp-vhdlpp_config-h vhdlpp_config.h
+
+Makefile: $(srcdir)/Makefile.in
+	cd ..; ./config.status --file=vhdlpp/$@
+
+dep:
+	mkdir dep
+
+vhdlpp@EXEEXT@: $O
+	$(CXX) -o vhdlpp@EXEEXT@ $(LDFLAGS) $O $(LIBS)
+
+%.o: $(srcdir)/../libmisc/%.cc
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) @DEPENDENCY_FLAG@ -c $< -o $*.o
+
+%.o: %.cc vhdlpp_config.h
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) @DEPENDENCY_FLAG@ -c $< -o $*.o
+	mv $*.d dep/$*.d
+
+lexor.o: lexor.cc parse.h
+
+parse.o: parse.cc
+
+lexor.cc: $(srcdir)/lexor.lex
+	$(LEX) -s -olexor.cc $(srcdir)/lexor.lex
+
+parse.cc parse.h: $(srcdir)/parse.y
+	$(YACC) --verbose -t -d -o parse.cc $(srcdir)/parse.y
+	mv parse.cc.h parse.h 2>/dev/null || mv parse.hh parse.h
+
+lexor_keyword.o: lexor_keyword.cc parse.h
+
+lexor_keyword.cc: $(srcdir)/lexor_keyword.gperf
+	gperf -o -i 7 --ignore-case -C -k 1-4,6,9,$$ -L ANSI-C -H keyword_hash -N check_identifier -t $(srcdir)/lexor_keyword.gperf > lexor_keyword.cc || (rm -f lexor_keyword.cc ; false)
+
+install: all installdirs $(libdir)/ivl$(suffix)/vhdlpp@EXEEXT@
+
+$(libdir)/ivl$(suffix)/vhdlpp@EXEEXT@: vhdlpp@EXEEXT@
+	$(INSTALL_PROGRAM) ./vhdlpp@EXEEXT@ "$(DESTDIR)$(libdir)/ivl$(suffix)/vhdlpp@EXEEXT@"
+
+installdirs: $(srcdir)/../mkinstalldirs
+	$(srcdir)/../mkinstalldirs "$(DESTDIR)$(libdir)/ivl$(suffix)"
+
+uninstall:
+	rm -f "$(DESTDIR)$(libdir)/ivl$(suffix)/ivhdlpp@EXEEXT@"
+
+stamp-vhdlpp_config-h: $(srcdir)/vhdlpp_config.h.in ../config.status
+	@rm -f $@
+	cd ..; ./config.status --header=vhdlpp/vhdlpp_config.h
+vhplpp_config.h: stamp-vhdlpp_config-h
+
+
+-include $(patsubst %.o, dep/%.d, $O)
diff --git a/vhdlpp/compiler.cc b/vhdlpp/compiler.cc
new file mode 100644
index 000000000..ab9d66166
--- /dev/null
+++ b/vhdlpp/compiler.cc
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+# include  "compiler.h"
+
+StringHeapLex lex_strings;
+
+StringHeapLex filename_strings;
diff --git a/vhdlpp/compiler.h b/vhdlpp/compiler.h
new file mode 100644
index 000000000..43d352e11
--- /dev/null
+++ b/vhdlpp/compiler.h
@@ -0,0 +1,33 @@
+#ifndef __compiler_H
+#define __compiler_H
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include  "StringHeap.h"
+
+const int GN_KEYWORD_2008  = 0x0001;
+
+// TRUE if processing is supposed to dump progress to stderr.
+extern bool verbose_flag;
+
+extern StringHeapLex lex_strings;
+
+extern StringHeapLex filename_strings;
+
+#endif
diff --git a/vhdlpp/entity.cc b/vhdlpp/entity.cc
new file mode 100644
index 000000000..13841e677
--- /dev/null
+++ b/vhdlpp/entity.cc
@@ -0,0 +1,73 @@
+
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include  "entity.h"
+# include  <fstream>
+# include  <iomanip>
+
+using namespace std;
+
+std::map<perm_string,Entity*> design_entities;
+
+static ostream& operator << (ostream&out, port_mode_t that)
+{
+      switch (that) {
+	  case PORT_NONE:
+	    out << "NO-PORT";
+	    break;
+	  case PORT_IN:
+	    out << "IN";
+	    break;
+	  case PORT_OUT:
+	    out << "OUT";
+	    break;
+	  default:
+	    out << "PORT-????";
+	    break;
+      }
+      return out;
+}
+
+static void dump_design_entity(ostream&out, Entity*obj)
+{
+      out << "entity " << obj->name << " file=" << obj->get_fileline() << endl;
+      if (obj->ports.size() == 0) {
+	    out << "    No ports" << endl;
+      } else {
+	    out << "    PORTS:" << endl;
+	    for (vector<InterfacePort*>::iterator cur = obj->ports.begin()
+		       ; cur != obj->ports.end() ; ++cur) {
+		  InterfacePort*item = *cur;
+		  out << setw(6) << "" << item->name
+		      << " : " << item->mode
+		      << ", type=" << item->type_name
+		      << ", file=" << item->get_fileline() << endl;
+	    }
+      }
+}
+
+void dump_design_entities(const char*path)
+{
+      ofstream file (path);
+      for (map<perm_string,Entity*>::iterator cur = design_entities.begin()
+		 ; cur != design_entities.end() ; ++cur) {
+	    dump_design_entity(file, cur->second);
+      }
+}
diff --git a/vhdlpp/entity.h b/vhdlpp/entity.h
new file mode 100644
index 000000000..1feb43fd2
--- /dev/null
+++ b/vhdlpp/entity.h
@@ -0,0 +1,68 @@
+#ifndef __entity_H
+#define __entity_H
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include  <map>
+# include  <vector>
+# include  "StringHeap.h"
+# include  "LineInfo.h"
+
+typedef enum { PORT_NONE=0, PORT_IN, PORT_OUT } port_mode_t;
+
+class InterfacePort : public LineInfo {
+    public:
+	// Port direction from the source code.
+      port_mode_t mode;
+	// Name of the port from the source code
+      perm_string name;
+	// Name of interface type as given in the source code.
+      perm_string type_name;
+};
+
+class Entity : public LineInfo {
+
+    public:
+      int elaborate();
+
+    public:
+      perm_string name;
+      std::vector<InterfacePort*> ports;
+
+};
+
+/*
+ * As the parser parses entities, it puts them into this map. It uses
+ * a map because sometimes it needs to look back at an entity by name.
+ */
+extern std::map<perm_string,Entity*> design_entities;
+
+/*
+ * Elaborate the collected entities, and return the number of
+ * elaboration errors.
+ */
+extern int elaborate_entities(void);
+
+/*
+ * Use this function to dump a description of the design entities to a
+ * file. This is for debug, not for any useful purpose.
+ */
+extern void dump_design_entities(const char*path);
+
+#endif
diff --git a/vhdlpp/entity_elaborate.cc b/vhdlpp/entity_elaborate.cc
new file mode 100644
index 000000000..699cc732d
--- /dev/null
+++ b/vhdlpp/entity_elaborate.cc
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include  "entity.h"
+# include  "compiler.h"
+# include  <iostream>
+# include  <fstream>
+# include  <iomanip>
+
+using namespace std;
+
+int elaborate_entities(void)
+{
+      int errors = 0;
+
+      for (map<perm_string,Entity*>::iterator cur = design_entities.begin()
+		 ; cur != design_entities.end() ; ++cur) {
+	    errors += cur->second->elaborate();
+      }
+
+      return errors;
+}
+
+int Entity::elaborate()
+{
+      int errors = 0;
+
+      if (verbose_flag)
+	    cerr << "Elaborate entity " << name << "..." << endl;
+
+      cout << "module " << name;
+
+	// If there are ports, emit them.
+      if (ports.size() > 0) {
+	    cout << "(";
+	    const char*sep = 0;
+	    for (vector<InterfacePort*>::iterator cur = ports.begin()
+		       ; cur != ports.end() ; ++cur) {
+		  InterfacePort*port = *cur;
+
+		    // FIXME: this is a stub. This port handling code
+		    // currently only supports std_logic signal tyes,
+		    // so just assert that the user asked for std_logic.
+		  if (port->type_name != "std_logic") {
+			cerr << "sorry: VHDL only supports std_logic ports."
+			     << " Expecting std_logic, but got \""
+			     << port->type_name << "\"" << endl;
+			errors += 1;
+		  }
+
+		  if (sep) cout << sep;
+		  else sep = ", ";
+
+		  switch (port->mode) {
+		      case PORT_NONE: // Should not happen
+			cout << "NO_PORT " << port->name;
+			break;
+		      case PORT_IN:
+			cout << "input " << port->name;
+			break;
+		      case PORT_OUT:
+			cout << "output " << port->name;
+			break;
+		  }
+	    }
+	    cout << ")";
+      }
+
+      cout << ";" << endl;
+
+      cout << "endmodule" << endl;
+
+      return errors;
+}
diff --git a/vhdlpp/lexor.lex b/vhdlpp/lexor.lex
new file mode 100644
index 000000000..d0d1d6b06
--- /dev/null
+++ b/vhdlpp/lexor.lex
@@ -0,0 +1,106 @@
+
+%option never-interactive
+%option nounput
+%option noyywrap
+
+%{
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include  "parse_api.h"
+# include  "lexor_keyword.h"
+# include  "parse_wrap.h"
+
+extern int lexor_keyword_code (const char*str, unsigned len);
+
+/*
+ * Lexical location information is passed in the yylloc variable to th
+ * parser. The file names, strings, are kept in a list so that I can
+ * re-use them. The set_file_name function will return a pointer to
+ * the name as it exists in the list (and delete the passed string.)
+ * If the name is new, it will be added to the list.
+ */
+extern YYLTYPE yylloc;
+
+static char* strdupnew(char const *str)
+{
+       return str ? strcpy(new char [strlen(str)+1], str) : 0;
+}
+
+static int comment_enter;
+
+%}
+
+%x CCOMMENT
+%x LCOMMENT
+
+W [ \t\b\f\r]+
+
+%%
+
+[ \t\b\f\r] { ; }
+\n { yylloc.first_line += 1; }
+
+  /* Single-line comments start with - - and run to the end of the
+     current line. These are very easy to handle. */
+
+"--".* { comment_enter = YY_START; BEGIN(LCOMMENT); }
+<LCOMMENT>.    { yymore(); }
+<LCOMMENT>\n   { yylloc.first_line += 1; BEGIN(comment_enter); }
+
+
+
+  /* The contents of C-style comments are ignored, like white space. */
+
+"/*" { comment_enter = YY_START; BEGIN(CCOMMENT); }
+<CCOMMENT>.    { ; }
+<CCOMMENT>\n   { yylloc.first_line += 1; }
+<CCOMMENT>"*/" { BEGIN(comment_enter); }
+
+[a-zA-Z_][a-zA-Z0-9_]* {
+      int rc = lexor_keyword_code(yytext, yyleng);
+      switch (rc) {
+	  case IDENTIFIER:
+	    yylval.text = strdupnew(yytext);
+	    break;
+	  default:
+	    break;
+      }
+      return rc;
+  }
+
+  /* Compound symbols */
+"<=" { return LEQ; }
+">=" { return GEQ; }
+":=" { return VASSIGN; }
+
+. { return yytext[0]; }
+
+%%
+
+extern void yyparse_set_filepath(const char*path);
+
+void reset_lexor(FILE*fd, const char*path)
+{
+      yylloc.text = path;
+      yylloc.first_line = 1;
+      yyrestart(fd);
+
+      yyparse_set_filepath(path);
+}
diff --git a/vhdlpp/lexor_keyword.gperf b/vhdlpp/lexor_keyword.gperf
new file mode 100644
index 000000000..b146ddb45
--- /dev/null
+++ b/vhdlpp/lexor_keyword.gperf
@@ -0,0 +1,47 @@
+/*
+ * We need this to prevent -Wextra (-W) from complaining that the mask and
+ * tokenType values are not initialized for the empty table entries.
+ */
+%define initializer-suffix ,0,0
+
+%{
+/* Command-line: gperf -o -i 1 --ignore-case -C -k 1-3,$ -L C -H keyword_hash -N check_identifier -tT lexor_keyword.gperf */
+
+#include "vhdlpp_config.h"
+#include <cstring>
+#include "compiler.h"
+#include "parse_api.h"
+#include "parse_wrap.h"
+
+%}
+struct lexor_keyword { const char*name; int mask; int tokenType; };
+%%
+abs,		GN_KEYWORD_2008,	K_abs
+access,		GN_KEYWORD_2008,	K_access
+all,		GN_KEYWORD_2008,	K_all
+and,		GN_KEYWORD_2008,	K_and
+architecture,	GN_KEYWORD_2008,	K_architecture
+begin,		GN_KEYWORD_2008,	K_begin
+end,		GN_KEYWORD_2008,	K_end
+entity,		GN_KEYWORD_2008,	K_entity
+in,		GN_KEYWORD_2008,	K_in
+is,		GN_KEYWORD_2008,	K_is
+library,	GN_KEYWORD_2008,	K_library
+of,		GN_KEYWORD_2008,	K_of
+out,		GN_KEYWORD_2008,	K_out
+port,		GN_KEYWORD_2008,	K_port
+use,		GN_KEYWORD_2008,	K_use
+%%
+
+int lexor_keyword_mask = GN_KEYWORD_2008;
+
+int lexor_keyword_code(const char*str, unsigned nstr)
+{
+      const struct lexor_keyword*rc = check_identifier(str, nstr);
+      if (rc == 0)
+	  return IDENTIFIER;
+      else if ((rc->mask & lexor_keyword_mask) == 0)
+          return IDENTIFIER;
+      else
+	  return rc->tokenType;
+}
diff --git a/vhdlpp/main.cc b/vhdlpp/main.cc
new file mode 100644
index 000000000..598187952
--- /dev/null
+++ b/vhdlpp/main.cc
@@ -0,0 +1,127 @@
+
+const char COPYRIGHT[] =
+          "Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+# include  "vhdlpp_config.h"
+# include  "version_base.h"
+# include  "version_tag.h"
+
+const char NOTICE[] =
+"  This program is free software; you can redistribute it and/or modify\n"
+"  it under the terms of the GNU General Public License as published by\n"
+"  the Free Software Foundation; either version 2 of the License, or\n"
+"  (at your option) any later version.\n"
+"\n"
+"  This program is distributed in the hope that it will be useful,\n"
+"  but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
+"  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
+"  GNU General Public License for more details.\n"
+"\n"
+"  You should have received a copy of the GNU General Public License along\n"
+"  with this program; if not, write to the Free Software Foundation, Inc.,\n"
+"  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.\n"
+;
+
+# include  "compiler.h"
+# include  "parse_api.h"
+# include  <cstdio>
+# include  <cstdlib>
+# include  <cstring>
+#if defined(HAVE_GETOPT_H)
+# include  <getopt.h>
+#endif
+
+
+bool verbose_flag = false;
+  // Where to dump design entities
+const char*dump_design_entities_path = 0;
+
+static void process_debug_token(const char*word)
+{
+      if (strcmp(word, "yydebug") == 0) {
+	    yydebug = 1;
+      } else if (strcmp(word, "no-yydebug") == 0) {
+	    yydebug = 0;
+      } else if (strncmp(word, "entities=", 9) == 0) {
+	    dump_design_entities_path = strdup(word+9);
+      }
+}
+
+int main(int argc, char*argv[])
+{
+      int opt;
+      int rc;
+
+      while ( (opt=getopt(argc, argv, "D:vV")) != EOF) switch (opt) {
+
+	  case 'D':
+	    process_debug_token(optarg);
+	    break;
+
+	  case 'v':
+	    fprintf(stderr, "Icarus Verilog VHDL Parse version "
+		    VERSION " (" VERSION_TAG ")\n\n");
+	    fprintf(stderr, "%s\n\n", COPYRIGHT);
+	    fputs(NOTICE, stderr);
+	    verbose_flag = true;
+	    break;
+
+	  case 'V':
+	    fprintf(stdout, "Icarus Verilog VHDL Parse version "
+		    VERSION " (" VERSION_TAG ")\n\n");
+	    fprintf(stdout, "%s\n\n", COPYRIGHT);
+	    fputs(NOTICE, stdout);
+	    break;
+
+      }
+
+      for (int idx = optind ; idx < argc ; idx += 1) {
+	    parse_errors = 0;
+	    FILE*fd = fopen(argv[idx], "r");
+	    if (fd == 0) {
+		  perror(argv[idx]);
+		  return 1;
+	    }
+
+	    reset_lexor(fd, argv[idx]);
+	    rc = yyparse();
+	    if (verbose_flag)
+		  fprintf(stderr, "yyparse() returns %d, parse_errors=%d\n", rc, parse_errors);
+
+	    if (parse_errors > 0) {
+		  fprintf(stderr, "%d errors parsing %s\n", parse_errors, argv[idx]);
+		  return 2;
+	    }
+
+	    fclose(fd);
+      }
+
+      if (dump_design_entities_path)
+	    dump_design_entities(dump_design_entities_path);
+
+      int elaborate_errors = 0;
+      elaborate_errors = elaborate_entities();
+      if (elaborate_errors > 0) {
+	    fprintf(stderr, "%d errors elaborating design.\n", elaborate_errors);
+	    return 3;
+      }
+
+      lex_strings.cleanup();
+      return 0;
+}
diff --git a/vhdlpp/parse.y b/vhdlpp/parse.y
new file mode 100644
index 000000000..0103167a5
--- /dev/null
+++ b/vhdlpp/parse.y
@@ -0,0 +1,309 @@
+
+%{
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include "vhdlpp_config.h"
+# include "compiler.h"
+# include "parse_api.h"
+# include  <cstdarg>
+# include  <list>
+
+inline void FILE_NAME(LineInfo*tmp, const struct yyltype&where)
+{
+      tmp->set_lineno(where.first_line);
+      tmp->set_file(filename_strings.make(where.text));
+}
+
+
+static void yyerror(const char*msg);
+
+static void errormsg(const YYLTYPE&loc, const char*msg, ...);
+int parse_errors = 0;
+%}
+
+%union {
+      port_mode_t port_mode;
+      char*text;
+
+      InterfacePort*interface_element;
+      std::list<InterfacePort*>* interface_list;
+};
+
+  /* The keywords are all tokens. */
+%token K_abs K_access K_after K_alias K_all K_and K_architecture
+%token K_array K_assert K_assume K_assume_guarantee K_attribute
+%token K_begin K_block K_body K_buffer K_bus
+%token K_case K_component K_configuration K_constant K_context K_cover
+%token K_default K_disconect K_downto
+%token K_else K_elsif K_end K_entity K_exit
+%token K_fairness K_file K_for K_force K_function
+%token K_generate K_generic K_group K_guarded
+%token K_if K_impure K_in K_internal K_inout K_is
+%token K_label K_library K_linkage K_literal K_loop
+%token K_map K_mod
+%token K_nand K_new K_next K_nor K_not K_null
+%token K_of K_on K_open K_or K_others K_out
+%token K_package K_parameter K_port K_postponed K_procedure K_process
+%token K_property K_protected K_pure
+%token K_range K_record K_register K_reject K_release K_rem K_report
+%token K_restrict K_restrict_guarantee K_return K_rol K_ror
+%token K_select K_sequence K_seerity K_signal K_shared
+%token K_sla K_sll K_sra K_srl K_string K_subtype
+%token K_then K_to K_transport K_type
+%token K_unaffected K_units K_until K_use
+%token K_variable K_vmode K_vprop K_vunit
+%token K_wait K_when K_while K_with
+%token K_xnor K_xor
+ /* Identifiers that are not keywords are identifiers. */
+%token <text> IDENTIFIER
+ /* compound symbols */
+%token LEQ GEQ VASSIGN
+
+ /* The rules may have types. */
+%type <interface_element> interface_element
+%type <interface_list>    interface_list entity_header port_clause
+%type <port_mode>  mode
+
+%%
+
+ /* The design_file is the root for the VHDL parse. */
+design_file : design_units ;
+
+architecture_body
+  : K_architecture IDENTIFIER
+    K_of IDENTIFIER
+    K_is
+    K_begin architecture_statement_part K_end K_architecture_opt ';'
+  | K_architecture IDENTIFIER
+    K_of IDENTIFIER
+    K_is
+    K_begin error K_end K_architecture_opt ';'
+      { errormsg(@1, "Syntax error in architecture statement.\n"); yyerrok; }
+  | K_architecture error ';'
+      { errormsg(@1, "Syntax error in architecture body.\n"); yyerrok; }
+  ;
+
+  /* The architecture_statement_part is a list of concurrent
+     statements. */
+architecture_statement_part
+  : architecture_statement_part concurrent_statement
+  | concurrent_statement
+  ;
+
+concurrent_signal_assignment_statement
+  : IDENTIFIER LEQ waveform ';'
+  ;
+
+concurrent_statement
+  : concurrent_signal_assignment_statement
+  ;
+
+context_clause : context_items | ;
+
+context_item
+  : library_clause
+  | use_clause
+  ;
+
+context_items
+  : context_items context_item
+  | context_item
+  ;
+
+
+design_unit
+  : context_clause library_unit
+  | error { errormsg(@1, "Invalid design_unit\n"); }
+  ;
+
+design_units
+  : design_units design_unit 
+  | design_unit
+  ;
+
+  /* As an entity is declared, add it to the map of design entities. */
+entity_declaration
+  : K_entity IDENTIFIER K_is entity_header K_end K_entity ';'
+      { Entity*tmp = new Entity;
+	FILE_NAME(tmp, @1);
+	  // Store the name
+	tmp->name = lex_strings.make($2);
+	delete[]$2;
+	  // Transfer the ports
+	std::list<InterfacePort*>*ports = $4;
+	while (ports->size() > 0) {
+	      tmp->ports.push_back(ports->front());
+	      ports->pop_front();
+	}
+	delete ports;
+	  // Save the entity in the entity map.
+	design_entities[tmp->name] = tmp;
+      }
+  ;
+
+entity_header
+  : port_clause
+      { $$ = $1; }
+  ;
+
+expression
+  : expression_logical
+  ;
+
+expression_logical
+  : relation K_and relation
+  | relation K_or relation
+  ;
+
+factor : primary ;
+
+  /* The interface_element is also an interface_declaration */
+interface_element
+  : IDENTIFIER ':' mode IDENTIFIER
+      { InterfacePort*tmp = new InterfacePort;
+	FILE_NAME(tmp, @1);
+	tmp->mode = $3;
+	tmp->name = lex_strings.make($1);
+	tmp->type_name = lex_strings.make($4);
+	delete[]$1;
+	delete[]$4;
+	$$ = tmp;
+      }
+  ;
+
+interface_list
+  : interface_list ';' interface_element
+      { std::list<InterfacePort*>*tmp = $1;
+	tmp->push_back($3);
+	$$ = tmp;
+      }
+  | interface_element
+      { std::list<InterfacePort*>*tmp = new std::list<InterfacePort*>;
+	tmp->push_back($1);
+	$$ = tmp;
+      }
+  ;
+
+library_clause
+  : K_library logical_name_list ';'
+  | K_library error ';'
+     { errormsg(@1, "Syntax error in library clause.\n"); yyerrok; }
+  ;
+
+  /* Collapse the primary_unit and secondary_unit of the library_unit
+     into this single set of rules. */
+library_unit
+  : entity_declaration
+  | architecture_body
+  ;
+
+logical_name : IDENTIFIER ;
+
+logical_name_list
+  : logical_name_list ',' logical_name
+  | logical_name
+  ;
+
+mode
+  : K_in  { $$ = PORT_IN; }
+  | K_out { $$ = PORT_OUT; }
+  ;
+
+port_clause
+  : K_port '(' interface_list ')' ';'
+      { $$ = $3; }
+  ;
+
+primary
+  : IDENTIFIER
+  ;
+
+relation : shift_expression ;
+
+selected_name
+  : IDENTIFIER '.' K_all
+  | IDENTIFIER '.' IDENTIFIER '.' K_all
+  ;
+
+selected_names
+  : selected_names ',' selected_name
+  | selected_name
+  ;
+
+shift_expression : simple_expression ;
+
+simple_expression : term ;
+
+term : factor ;
+
+use_clause
+  : K_use selected_names ';'
+  | K_use error ';'
+     { errormsg(@1, "Syntax error in use clause.\n"); yyerrok; }
+  ;
+
+waveform
+  : waveform_elements
+  | K_unaffected
+  ;
+
+waveform_elements
+  : waveform_elements ',' waveform_element
+  | waveform_element
+  ;
+
+waveform_element
+  : expression
+  | K_null
+  ;
+
+  /* Some keywords are optional in some contexts. In all such cases, a
+     similar rule is used, as described here. */
+K_architecture_opt : K_architecture | ;
+
+%%
+
+static void yyerror(const char*msg)
+{
+      fprintf(stderr, "%s\n", msg);
+      parse_errors += 1;
+}
+
+static const char*file_path = "";
+
+static void errormsg(const YYLTYPE&loc, const char*fmt, ...)
+{
+      va_list ap;
+      va_start(ap, fmt);
+
+      fprintf(stderr, "%s:%d: ", file_path, loc.first_line);
+      vfprintf(stderr, fmt, ap);
+      va_end(ap);
+      parse_errors += 1;
+}
+
+/*
+ * This is used only by the lexor, to set the file path used in error
+ * messages.
+ */
+void yyparse_set_filepath(const char*path)
+{
+      file_path = path;
+}
diff --git a/vhdlpp/parse_api.h b/vhdlpp/parse_api.h
new file mode 100644
index 000000000..9d7551e5d
--- /dev/null
+++ b/vhdlpp/parse_api.h
@@ -0,0 +1,61 @@
+#ifndef __parse_api_H
+#define __parse_api_H
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+# include  <cstdio>
+# include  "entity.h"
+
+/*
+ * The vlltype supports the passing of detailed source file location
+ * information between the lexical analyzer and the parser. Defining
+ * YYLTYPE compels the lexor to use this type and not something other.
+ */
+struct yyltype {
+      unsigned first_line;
+      unsigned first_column;
+      unsigned last_line;
+      unsigned last_column;
+      const char*text;
+};
+# define YYLTYPE struct yyltype
+
+/*
+ * The reset_lexor function takes the fd and makes it the input file
+ * for the lexor. The path argument is used in lexor/parser error messages.
+ */
+extern void reset_lexor(FILE*fd, const char*path);
+
+extern int yylex(void);
+
+extern int yyparse(void);
+
+/*
+ * Set this to a non-zero value to enable parser debug output.
+ */
+extern int yydebug;
+
+/*
+ * The parser counts the errors that is handed in the parse_errors
+ * variable. For a clean compile, this value should not change. (The
+ * caller sets its initial value.)
+ */
+extern int parse_errors;
+
+#endif
diff --git a/vhdlpp/parse_wrap.h b/vhdlpp/parse_wrap.h
new file mode 100644
index 000000000..1b835d5a9
--- /dev/null
+++ b/vhdlpp/parse_wrap.h
@@ -0,0 +1,31 @@
+#ifndef __parse_wrap_H
+#define __parse_wrap_H
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+/*
+ * This header wraps the parse.h header file that is generated from
+ * the parse.y source file. This is used to include definitions that
+ * are needed by the parse type, etc.
+ */
+
+# include  <list>
+# include  "parse.h"
+
+#endif
diff --git a/vhdlpp/vhdlpp_config.h.in b/vhdlpp/vhdlpp_config.h.in
new file mode 100644
index 000000000..b48d2caef
--- /dev/null
+++ b/vhdlpp/vhdlpp_config.h.in
@@ -0,0 +1,40 @@
+#ifndef __vhdlpp_config_H                                           /* -*- c++ -*- */
+#define __vhdlpp_config_H
+/*
+ * Copyright (c) 2011 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
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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 General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#if defined(__cplusplus)
+#  if !defined(__GNUC__)
+     using namespace std;
+#  elif (__GNUC__ == 3)
+     using namespace std;
+#  endif
+#endif
+
+# undef HAVE_GETOPT_H
+# undef HAVE_INTTYPES_H
+# undef HAVE_LIBIBERTY_H
+# undef HAVE_FCHMOD
+# undef HAVE_SYS_WAIT_H
+
+#ifdef HAVE_INTTYPES_H
+# include  <inttypes.h>
+#endif
+
+#endif /* __config_H */