Fluid: restructuring and rejuvenation of the source code.

* Add classes for application and project
* Removed all globals from Fluid.h
* Extracting args and project history into their own classes
* Moving globals into Application class
* Initialize values inside headers for some classes.
* Undo functionality wrapped in a class inside Project.
* File reader and writer are now linked to a project.
* Avoid global project access
* Nodes (former Types) will be managed by a new Tree class.
* Removed static members (hidden globals) form Node/Fl_Type.
* Adding Tree iterator.
* Use nullptr instead of 0, NULL, or 0L
* Renamed Fl_..._Type to ..._Node, FL_OVERRIDE -> override
* Renaming ..._type to ...::prototype
* Splitting Widget Panel into multiple files.
* Moved callback code into widget panel file.
* Cleaning up Fluid_Image -> Image_asset
* Moving Fd_Snap_Action into new namespace fld::app::Snap_Action etc.
* Moved mergeback into proj folder.
* `enum ID` is now `enum class Type`.

8 files changed, 154 insertions, 123 deletions

diff --git a/fluid/tools/ExternalCodeEditor_UNIX.cxx b/fluid/tools/ExternalCodeEditor_UNIX.cxx
index bf472d896..9e9ffd00e 100644
--- a/fluid/tools/ExternalCodeEditor_UNIX.cxx
+++ b/fluid/tools/ExternalCodeEditor_UNIX.cxx
@@ -5,8 +5,8 @@
 
 #include "ExternalCodeEditor_UNIX.h"
 
-#include "app/fluid.h"
-#include "app/project.h"
+#include "Fluid.h"
+#include "Project.h"
 
 #include <FL/Fl.H>      /* Fl_Timeout_Handler.. */
 #include <FL/fl_ask.H>  /* fl_alert() */
@@ -23,9 +23,11 @@
 #include <stdlib.h>     /* free().. */
 #include <stdio.h>      /* snprintf().. */
 
+using namespace fld;
+
 // Static local data
 static int L_editors_open = 0;                          // keep track of #editors open
-static Fl_Timeout_Handler L_update_timer_cb = 0;        // app's update timer callback
+static Fl_Timeout_Handler L_update_timer_cb = nullptr;        // app's update timer callback
 
 // [Static/Local] See if file exists
 static int is_file(const char *filename) {
@@ -57,7 +59,7 @@ static int is_dir(const char *dirname) {
  */
 ExternalCodeEditor::ExternalCodeEditor() {
   pid_        = -1;
-  filename_   = 0;
+  filename_   = nullptr;
   file_mtime_ = 0;
   file_size_  = 0;
   alert_pipe_[0] = alert_pipe_[1] = -1;
@@ -69,11 +71,11 @@ ExternalCodeEditor::ExternalCodeEditor() {
  This also closes the external editor.
  */
 ExternalCodeEditor::~ExternalCodeEditor() {
-  if ( G_debug )
+  if ( Fluid.debug_external_editor )
     printf("ExternalCodeEditor() DTOR CALLED (this=%p, pid=%ld)\n",
            (void*)this, (long)pid_);
   close_editor();   // close editor, delete tmp file
-  set_filename(0);  // free()s filename
+  set_filename(nullptr);  // free()s filename
 
   if (alert_pipe_open_) {
     Fl::remove_fd(alert_pipe_[0]);
@@ -85,12 +87,12 @@ ExternalCodeEditor::~ExternalCodeEditor() {
 /**
  Set the filename for the file we wish to edit.
  Handles memory allocation/free.
- If set to NULL, frees memory.
+ If set to nullptr, frees memory.
  \param[in] val new filename
  */
 void ExternalCodeEditor::set_filename(const char *val) {
   if ( filename_ ) free((void*)filename_);
-  filename_ = val ? fl_strdup(val) : 0;
+  filename_ = val ? fl_strdup(val) : nullptr;
 }
 
 /**
@@ -105,7 +107,7 @@ int ExternalCodeEditor::is_editing() {
  Wait for editor to close
  */
 void ExternalCodeEditor::close_editor() {
-  if ( G_debug ) printf("close_editor() called: pid=%ld\n", long(pid_));
+  if ( Fluid.debug_external_editor ) printf("close_editor() called: pid=%ld\n", long(pid_));
   // Wait until editor is closed + reaped
   while ( is_editing() ) {
     switch ( reap_editor() ) {
@@ -119,7 +121,7 @@ void ExternalCodeEditor::close_editor() {
         switch ( fl_choice("Please close external editor\npid=%ld file=%s",
                            "Force Close",       // button 0
                            "Closed",            // button 1
-                           0,                   // button 2
+                           nullptr,                   // button 2
                            long(pid_), filename() ) ) {
           case 0:       // Force Close
             kill_editor();
@@ -141,7 +143,7 @@ void ExternalCodeEditor::close_editor() {
  The dtor calls this to ensure no editors remain running when fluid exits.
  */
 void ExternalCodeEditor::kill_editor() {
-  if ( G_debug ) printf("kill_editor() called: pid=%ld\n", (long)pid_);
+  if ( Fluid.debug_external_editor ) printf("kill_editor() called: pid=%ld\n", (long)pid_);
   if ( !is_editing() ) return;  // editor not running? return..
   kill(pid_, SIGTERM);          // kill editor
   int wcount = 0;
@@ -164,7 +166,7 @@ void ExternalCodeEditor::kill_editor() {
         }
         continue;
       case 1:  // process reaped (reap_editor() sets pid_ to -1)
-        if ( G_debug )
+        if ( Fluid.debug_external_editor )
           printf("*** REAPED KILLED EXTERNAL EDITOR: PID %ld\n", (long)pid_reaped);
         break;
     }
@@ -185,7 +187,7 @@ void ExternalCodeEditor::kill_editor() {
  \return -1 error getting file info (strerror() has reason)
 */
 int ExternalCodeEditor::handle_changes(const char **code, int force) {
-  code[0] = 0;
+  code[0] = nullptr;
   if ( !is_editing() ) return 0;
   // Get current time/size info, see if file changed
   int changed = 0;
@@ -239,13 +241,13 @@ int ExternalCodeEditor::remove_tmpfile() {
   if ( !tmpfile ) return 0;
   // Filename set? remove (if exists) and zero filename/mtime/size
   if ( is_file(tmpfile) ) {
-    if ( G_debug ) printf("Removing tmpfile '%s'\n", tmpfile);
+    if ( Fluid.debug_external_editor ) printf("Removing tmpfile '%s'\n", tmpfile);
     if ( remove(tmpfile) < 0 ) {
       fl_alert("WARNING: Can't remove() '%s': %s", tmpfile, strerror(errno));
       return -1;
     }
   }
-  set_filename(0);
+  set_filename(nullptr);
   file_mtime_ = 0;
   file_size_  = 0;
   return 1;
@@ -268,7 +270,7 @@ const char* ExternalCodeEditor::tmpdir_name() {
 void ExternalCodeEditor::tmpdir_clear() {
   const char *tmpdir = tmpdir_name();
   if ( is_dir(tmpdir) ) {
-    if ( G_debug ) printf("Removing tmpdir '%s'\n", tmpdir);
+    if ( Fluid.debug_external_editor ) printf("Removing tmpdir '%s'\n", tmpdir);
     if ( rmdir(tmpdir) < 0 ) {
       fl_alert("WARNING: Can't rmdir() '%s': %s", tmpdir, strerror(errno));
     }
@@ -278,7 +280,7 @@ void ExternalCodeEditor::tmpdir_clear() {
 /**
  Creates temp dir (if doesn't exist) and returns the dirname
  as a static string.
- \return NULL on error, dialog shows reason.
+ \return nullptr on error, dialog shows reason.
  */
 const char* ExternalCodeEditor::create_tmpdir() {
   const char *dirname = tmpdir_name();
@@ -286,7 +288,7 @@ const char* ExternalCodeEditor::create_tmpdir() {
     if ( mkdir(dirname, 0777) < 0 ) {
       fl_alert("can't create directory '%s': %s",
         dirname, strerror(errno));
-      return NULL;
+      return nullptr;
     }
   }
   return dirname;
@@ -294,13 +296,13 @@ const char* ExternalCodeEditor::create_tmpdir() {
 
 /**
  Returns temp filename in static buffer.
- \return NULL if can't, posts dialog explaining why.
+ \return nullptr if can't, posts dialog explaining why.
  */
 const char* ExternalCodeEditor::tmp_filename() {
   static char path[FL_PATH_MAX+1];
   const char *tmpdir = create_tmpdir();
-  if ( !tmpdir ) return 0;
-  const char *ext = g_project.code_file_name.c_str();   // e.g. ".cxx"
+  if ( !tmpdir ) return nullptr;
+  const char *ext = Fluid.proj.code_file_name.c_str();   // e.g. ".cxx"
   snprintf(path, FL_PATH_MAX, "%s/%p%s", tmpdir, (void*)this, ext);
   path[FL_PATH_MAX] = 0;
   return path;
@@ -308,12 +310,12 @@ const char* ExternalCodeEditor::tmp_filename() {
 
 /**
  Save string 'code' to 'filename', returning file's mtime/size.
- 'code' can be NULL -- writes an empty file if so.
+ 'code' can be nullptr -- writes an empty file if so.
  \return 0 on success
  \return -1 on error (posts dialog with reason)
  */
 static int save_file(const char *filename, const char *code) {
-  if ( code == 0 ) code = "";   // NULL? write an empty file
+  if ( code == nullptr ) code = "";   // nullptr? write an empty file
   int fd = open(filename, O_WRONLY|O_CREAT, 0666);
   if ( fd == -1 ) {
     fl_alert("ERROR: open() '%s': %s", filename, strerror(errno));
@@ -336,7 +338,7 @@ static int save_file(const char *filename, const char *code) {
 
 /**
  Convert string 's' to array of argv[], useful for execve().
-  - 's' will be modified (words will be NULL separated)
+  - 's' will be modified (words will be nullptr separated)
   - argv[] will end up pointing to the words of 's'
   - Caller must free argv with: free(argv);
  \return -1 in case of memory allocation error
@@ -346,14 +348,14 @@ static int make_args(char *s,         // string containing words (gets trashed!)
                      int *aargc,      // pointer to argc
                      char ***aargv) { // pointer to argv
   char *ss, **argv;
-  if ((argv=(char**)malloc(sizeof(char*) * (strlen(s)/2)))==NULL) {
+  if ((argv=(char**)malloc(sizeof(char*) * (strlen(s)/2)))==nullptr) {
     return -1;
   }
   int t;
-  for(t=0; (t==0)?(ss=strtok(s," \t")):(ss=strtok(0," \t")); t++) {
+  for(t=0; (t==0)?(ss=strtok(s," \t")):(ss=strtok(nullptr," \t")); t++) {
     argv[t] = ss;
   }
-  argv[t] = 0;
+  argv[t] = nullptr;
   aargv[0] = argv;
   aargc[0] = t;
   return(t);
@@ -383,7 +385,7 @@ void ExternalCodeEditor::open_alert_pipe() {
  */
 int ExternalCodeEditor::start_editor(const char *editor_cmd,
                                      const char *filename) {
-  if ( G_debug ) printf("start_editor() cmd='%s', filename='%s'\n",
+  if ( Fluid.debug_external_editor ) printf("start_editor() cmd='%s', filename='%s'\n",
                         editor_cmd, filename);
   char cmd[1024];
   snprintf(cmd, sizeof(cmd), "%s %s", editor_cmd, filename);
@@ -399,7 +401,7 @@ int ExternalCodeEditor::start_editor(const char *editor_cmd,
       // NOTE: no FLTK calls after a fork. Use a pipe to tell the app if the
       //       command can't launch
       int nargs;
-      char **args = 0;
+      char **args = nullptr;
       if (make_args(cmd, &nargs, &args) > 0) {
         execvp(args[0], args);  // run command - doesn't return if succeeds
         if (alert_pipe_open_) {
@@ -416,7 +418,7 @@ int ExternalCodeEditor::start_editor(const char *editor_cmd,
     default:    // parent
       if ( L_editors_open++ == 0 )  // first editor? start timers
         { start_update_timer(); }
-      if ( G_debug )
+      if ( Fluid.debug_external_editor )
         printf("--- EDITOR STARTED: pid_=%ld #open=%d\n", (long)pid_, L_editors_open);
       break;
   }
@@ -426,7 +428,7 @@ int ExternalCodeEditor::start_editor(const char *editor_cmd,
 /**
  Try to reap external editor process.
 
- If 'pid_reaped' not NULL, returns PID of reaped editor.
+ If 'pid_reaped' not nullptr, returns PID of reaped editor.
 
  \return -2: editor not open
  \return -1: waitpid() failed (errno has reason)
@@ -453,7 +455,7 @@ int ExternalCodeEditor::reap_editor(pid_t *pid_reaped) {
         { stop_update_timer(); }
       break;
   }
-  if ( G_debug )
+  if ( Fluid.debug_external_editor )
     printf("*** EDITOR REAPED: pid=%ld #open=%d\n", long(wpid), L_editors_open);
   return 1;
 }
@@ -462,7 +464,7 @@ int ExternalCodeEditor::reap_editor(pid_t *pid_reaped) {
  Open external editor using 'editor_cmd' to edit 'code'.
 
  'code' contains multiline code to be edited as a temp file.
- 'code' can be NULL -- edits an empty file if so.
+ 'code' can be nullptr -- edits an empty file if so.
 
  \return 0 if succeeds
  \return -1 if can't open editor (already open, etc),
@@ -492,7 +494,7 @@ int ExternalCodeEditor::open_editor(const char *editor_cmd,
             filename(), (long)pid_);
           return 0;
         case 1:        // process reaped, wpid is pid reaped
-          if ( G_debug )
+          if ( Fluid.debug_external_editor )
             printf("*** REAPED EXTERNAL EDITOR: PID %ld\n", (long)wpid);
           break;        // fall thru to open new editor instance
       }
@@ -512,7 +514,7 @@ int ExternalCodeEditor::open_editor(const char *editor_cmd,
   file_mtime_ = sbuf.st_mtime;
   file_size_  = sbuf.st_size;
   if ( start_editor(editor_cmd, filename()) < 0 ) { // open file in external editor
-    if ( G_debug ) printf("Editor failed to start\n");
+    if ( Fluid.debug_external_editor ) printf("Editor failed to start\n");
     return -1;  // errors were shown in dialog
   }
   return 0;
@@ -523,7 +525,7 @@ int ExternalCodeEditor::open_editor(const char *editor_cmd,
  */
 void ExternalCodeEditor::start_update_timer() {
   if ( !L_update_timer_cb ) return;
-  if ( G_debug ) printf("--- TIMER: STARTING UPDATES\n");
+  if ( Fluid.debug_external_editor ) printf("--- TIMER: STARTING UPDATES\n");
   Fl::add_timeout(2.0, L_update_timer_cb);
 }
 
@@ -532,7 +534,7 @@ void ExternalCodeEditor::start_update_timer() {
  */
 void ExternalCodeEditor::stop_update_timer() {
   if ( !L_update_timer_cb ) return;
-  if ( G_debug ) printf("--- TIMER: STOPPING UPDATES\n");
+  if ( Fluid.debug_external_editor ) printf("--- TIMER: STOPPING UPDATES\n");
   Fl::remove_timeout(L_update_timer_cb);
 }
 
diff --git a/fluid/tools/ExternalCodeEditor_UNIX.h b/fluid/tools/ExternalCodeEditor_UNIX.h
index 644f22afa..2142d5a10 100644
--- a/fluid/tools/ExternalCodeEditor_UNIX.h
+++ b/fluid/tools/ExternalCodeEditor_UNIX.h
@@ -7,7 +7,7 @@
 #ifndef _EXTCODEEDITOR_H
 #define _EXTCODEEDITOR_H
 
-#include "app/fluid.h"
+#include "Fluid.h"
 
 #include <FL/Fl.H>
 
@@ -42,7 +42,7 @@ public:
   ExternalCodeEditor();
   ~ExternalCodeEditor();
   int is_editing();
-  int reap_editor(pid_t *pid_reaped=NULL);
+  int reap_editor(pid_t *pid_reaped=nullptr);
   void close_editor();
   const char *filename() { return filename_; }
   int open_editor(const char *editor_cmd, const char *code);
diff --git a/fluid/tools/ExternalCodeEditor_WIN32.cxx b/fluid/tools/ExternalCodeEditor_WIN32.cxx
index 09688d16a..64d791400 100644
--- a/fluid/tools/ExternalCodeEditor_WIN32.cxx
+++ b/fluid/tools/ExternalCodeEditor_WIN32.cxx
@@ -17,8 +17,8 @@
 //      Note: This entire file Windows only.
 
 #include "tools/ExternalCodeEditor_WIN32.h"
-#include "app/fluid.h"
-#include "app/project.h"
+#include "Fluid.h"
+#include "Project.h"
 
 #include <FL/Fl.H>      // Fl_Timeout_Handler..
 #include <FL/fl_ask.H>  // fl_alert()
@@ -28,17 +28,17 @@
 #include <stdio.h>      // snprintf()
 #include <stdlib.h>
 
-extern int G_debug;     // defined in fluid.cxx
+using namespace fld;
 
 // Static local data
 static int L_editors_open = 0;                          // keep track of #editors open
 static Fl_Timeout_Handler L_update_timer_cb = 0;        // app's update timer callback
-static wchar_t *wbuf = NULL;
-static char *abuf = NULL;
+static wchar_t *wbuf = nullptr;
+static char *abuf = nullptr;
 
 static wchar_t *utf8_to_wchar(const char *utf8, wchar_t *&wbuf, int lg = -1) {
   unsigned len = (lg >= 0) ? (unsigned)lg : (unsigned)strlen(utf8);
-  unsigned wn = fl_utf8toUtf16(utf8, len, NULL, 0) + 1; // Query length
+  unsigned wn = fl_utf8toUtf16(utf8, len, nullptr, 0) + 1; // Query length
   wbuf = (wchar_t *)realloc(wbuf, sizeof(wchar_t) * wn);
   wn = fl_utf8toUtf16(utf8, len, (unsigned short *)wbuf, wn); // Convert string
   wbuf[wn] = 0;
@@ -47,7 +47,7 @@ static wchar_t *utf8_to_wchar(const char *utf8, wchar_t *&wbuf, int lg = -1) {
 
 static char *wchar_to_utf8(const wchar_t *wstr, char *&utf8) {
   unsigned len = (unsigned)wcslen(wstr);
-  unsigned wn = fl_utf8fromwc(NULL, 0, wstr, len) + 1; // query length
+  unsigned wn = fl_utf8fromwc(nullptr, 0, wstr, len) + 1; // query length
   utf8 = (char *)realloc(utf8, wn);
   wn = fl_utf8fromwc(utf8, wn, wstr, len); // convert string
   utf8[wn] = 0;
@@ -68,7 +68,7 @@ static const char *get_ms_errmsg() {
   DWORD msize = 0;
 
   // Get error message from Windows
-  msize = FormatMessageW(flags, 0, lastErr, langid, (LPWSTR)&mbuf, 0, NULL);
+  msize = FormatMessageW(flags, 0, lastErr, langid, (LPWSTR)&mbuf, 0, nullptr);
   if ( msize == 0 ) {
     _snprintf(emsg, sizeof(emsg), "Error #%ld", (unsigned long)lastErr);
   } else {
@@ -119,7 +119,7 @@ ExternalCodeEditor::~ExternalCodeEditor() {
 }
 
 // [Protected] Set the filename. Handles memory allocation/free
-//     If set to NULL, frees memory.
+//     If set to nullptr, frees memory.
 //
 void ExternalCodeEditor::set_filename(const char *val) {
   if ( filename_ ) free((void*)filename_);
@@ -137,7 +137,7 @@ static BOOL CALLBACK terminate_app_enum(HWND hwnd, LPARAM lParam) {
   GetWindowThreadProcessId(hwnd, &dwID);
   if (dwID == (DWORD)lParam) {
     PostMessage(hwnd, WM_CLOSE, 0, 0);
-    if ( G_debug )
+    if ( Fluid.debug_external_editor )
       printf("terminate_app_enum() sends WIN_CLOSE to hwnd=%p\n", (void*)hwnd);
   }
   return TRUE;
@@ -154,12 +154,12 @@ static int terminate_app(DWORD pid, DWORD msecTimeout) {
   // Wait on handle. If it closes, great. If it times out, use TerminateProcess()
   int ret = 0;
   if ( WaitForSingleObject(hProc, msecTimeout) != WAIT_OBJECT_0 ) {
-    if ( G_debug ) {
+    if ( Fluid.debug_external_editor ) {
       printf("WARNING: sent WIN_CLOSE, but timeout after %ld msecs.."
              "trying TerminateProcess\n", msecTimeout);
     }
     if ( TerminateProcess(hProc, 0) == 0 ) {
-      if ( G_debug ) {
+      if ( Fluid.debug_external_editor ) {
         printf("ERROR: TerminateProcess() for pid=%ld failed: %s\n",
                long(pid), get_ms_errmsg());
       }
@@ -176,7 +176,7 @@ static int terminate_app(DWORD pid, DWORD msecTimeout) {
 
 // [Protected] Wait for editor to close
 void ExternalCodeEditor::close_editor() {
-  if ( G_debug ) printf("close_editor() called: pid=%ld\n", long(pinfo_.dwProcessId));
+  if ( Fluid.debug_external_editor ) printf("close_editor() called: pid=%ld\n", long(pinfo_.dwProcessId));
   // Wait until editor is closed + reaped
   while ( is_editing() ) {
     switch ( reap_editor() ) {
@@ -210,7 +210,7 @@ void ExternalCodeEditor::close_editor() {
 //   The dtor calls this to ensure no editors remain running when fluid exits.
 //
 void ExternalCodeEditor::kill_editor() {
-  if ( G_debug )
+  if ( Fluid.debug_external_editor )
     printf("kill_editor() called: pid=%ld\n", (long)pinfo_.dwProcessId);
   if ( !is_editing() ) return;
   switch ( terminate_app(pinfo_.dwProcessId, 500) ) {  // kill editor, wait up to 1/2 sec to die
@@ -222,7 +222,7 @@ void ExternalCodeEditor::kill_editor() {
     case 0: {  // success -- process reaped
       DWORD pid = pinfo_.dwProcessId;     // save pid
       reap_cleanup();                     // clears pinfo_
-      if ( G_debug )
+      if ( Fluid.debug_external_editor )
         printf("*** kill_editor() REAP pid=%ld #open=%ld\n",
                long(pid), long(L_editors_open));
       break;
@@ -252,10 +252,10 @@ int ExternalCodeEditor::handle_changes(const char **code, int force) {
   HANDLE fh = CreateFileW(wbuf,           // file to read
                          GENERIC_READ,    // reading only
                          FILE_SHARE_READ, // sharing -- allow read share; just getting file size
-                         NULL,            // security
+                         nullptr,            // security
                          OPEN_EXISTING,   // create flags -- must exist
                          0,               // misc flags
-                         NULL);           // templates
+                         nullptr);           // templates
   if ( fh == INVALID_HANDLE_VALUE ) return -1;
   LARGE_INTEGER fsize;
   // Get file size
@@ -315,18 +315,18 @@ int ExternalCodeEditor::handle_changes(const char **code, int force) {
 //
 int ExternalCodeEditor::remove_tmpfile() {
   const char *tmpfile = filename();
-  if ( G_debug ) printf("remove_tmpfile() '%s'\n", tmpfile ? tmpfile : "(empty)");
+  if ( Fluid.debug_external_editor ) printf("remove_tmpfile() '%s'\n", tmpfile ? tmpfile : "(empty)");
   if ( !tmpfile ) return 0;
   // Filename set? remove (if exists) and zero filename/mtime/size
   if ( is_file(tmpfile) ) {
-    if ( G_debug ) printf("Removing tmpfile '%s'\n", tmpfile);
+    if ( Fluid.debug_external_editor ) printf("Removing tmpfile '%s'\n", tmpfile);
     utf8_to_wchar(tmpfile, wbuf);
     if (DeleteFileW(wbuf) == 0) {
       fl_alert("WARNING: Can't DeleteFile() '%s': %s", tmpfile, get_ms_errmsg());
       return -1;
     }
   } else {
-    if ( G_debug ) printf("remove_tmpfile(): is_file(%s) failed\n", tmpfile);
+    if ( Fluid.debug_external_editor ) printf("remove_tmpfile(): is_file(%s) failed\n", tmpfile);
   }
   set_filename(0);
   memset(&file_mtime_, 0, sizeof(file_mtime_));
@@ -348,7 +348,7 @@ const char* ExternalCodeEditor::tmpdir_name() {
   static char dirname[100];
   _snprintf(dirname, sizeof(dirname), "%s.fluid-%ld",
     tempdir, (long)GetCurrentProcessId());
-  if ( G_debug ) printf("tmpdir_name(): '%s'\n", dirname);
+  if ( Fluid.debug_external_editor ) printf("tmpdir_name(): '%s'\n", dirname);
   return dirname;
 }
 
@@ -358,7 +358,7 @@ const char* ExternalCodeEditor::tmpdir_name() {
 void ExternalCodeEditor::tmpdir_clear() {
   const char *tmpdir = tmpdir_name();
   if ( is_dir(tmpdir) ) {
-    if ( G_debug ) printf("Removing tmpdir '%s'\n", tmpdir);
+    if ( Fluid.debug_external_editor ) printf("Removing tmpdir '%s'\n", tmpdir);
     utf8_to_wchar(tmpdir, wbuf);
     if ( RemoveDirectoryW(wbuf) == 0 ) {
       fl_alert("WARNING: Can't RemoveDirectory() '%s': %s",
@@ -368,7 +368,7 @@ void ExternalCodeEditor::tmpdir_clear() {
 }
 
 // [Protected] Creates temp dir (if doesn't exist) and returns the dirname
-// as a static string. Returns NULL on error, dialog shows reason.
+// as a static string. Returns nullptr on error, dialog shows reason.
 //
 const char* ExternalCodeEditor::create_tmpdir() {
   const char *dirname = tmpdir_name();
@@ -377,27 +377,27 @@ const char* ExternalCodeEditor::create_tmpdir() {
     if (CreateDirectoryW(wbuf, 0) == 0) {
       fl_alert("can't create directory '%s': %s",
         dirname, get_ms_errmsg());
-      return NULL;
+      return nullptr;
     }
   }
   return dirname;
 }
 
 // [Protected] Returns temp filename in static buffer.
-//    Returns NULL if can't, posts dialog explaining why.
+//    Returns nullptr if can't, posts dialog explaining why.
 //
 const char* ExternalCodeEditor::tmp_filename() {
   static char path[512];
   const char *tmpdir = create_tmpdir();
   if ( !tmpdir ) return 0;
-  const char *ext  = g_project.code_file_name.c_str();    // e.g. ".cxx"
+  const char *ext  = Fluid.proj.code_file_name.c_str();    // e.g. ".cxx"
   _snprintf(path, sizeof(path), "%s\\%p%s", tmpdir, (void*)this, ext);
   path[sizeof(path)-1] = 0;
   return path;
 }
 
 // [Static/Local] Save string 'code' to 'filename', returning file's mtime/size
-// 'code' can be NULL -- writes an empty file if so.
+// 'code' can be nullptr -- writes an empty file if so.
 // Returns:
 //    0 on success
 //   -1 on error (posts dialog with reason)
@@ -406,17 +406,17 @@ static int save_file(const char *filename,
                      const char *code,
                      FILETIME &file_mtime,        // return these since in win32 it's..
                      LARGE_INTEGER &file_size) {  // ..efficient to get while file open
-  if ( code == 0 ) code = "";   // NULL? write an empty file
+  if ( code == 0 ) code = "";   // nullptr? write an empty file
   memset(&file_mtime, 0, sizeof(file_mtime));
   memset(&file_size, 0, sizeof(file_size));
   utf8_to_wchar(filename, wbuf);
   HANDLE fh = CreateFileW(wbuf,                   // filename
                          GENERIC_WRITE,           // write only
                          0,                       // sharing -- no share during write
-                         NULL,                    // security
+                         nullptr,                    // security
                          CREATE_ALWAYS,           // create flags -- recreate
                          FILE_ATTRIBUTE_NORMAL,   // misc flags
-                         NULL);                   // templates
+                         nullptr);                   // templates
   if ( fh == INVALID_HANDLE_VALUE ) {
     fl_alert("ERROR: couldn't create file '%s': %s",
              filename, get_ms_errmsg());
@@ -426,7 +426,7 @@ static int save_file(const char *filename,
   DWORD clen = (DWORD)strlen(code);
   DWORD count = 0;
   int ret = 0;
-  if ( WriteFile(fh, code, clen, &count, NULL) == 0 ) {
+  if ( WriteFile(fh, code, clen, &count, nullptr) == 0 ) {
     fl_alert("ERROR: WriteFile() '%s': %s", filename, get_ms_errmsg());
     ret = -1; // fallthru to CloseHandle()
   } else if ( count != clen ) {
@@ -459,7 +459,7 @@ static int save_file(const char *filename,
 //
 int ExternalCodeEditor::start_editor(const char *editor_cmd,
                                      const char *filename) {
-  if ( G_debug ) printf("start_editor() cmd='%s', filename='%s'\n",
+  if ( Fluid.debug_external_editor ) printf("start_editor() cmd='%s', filename='%s'\n",
                         editor_cmd, filename);
   // Startup info
   STARTUPINFOW sinfo;
@@ -474,14 +474,14 @@ int ExternalCodeEditor::start_editor(const char *editor_cmd,
   _snprintf(cmd, sizeof(cmd), "%s %s", editor_cmd, filename);
   utf8_to_wchar(cmd, wbuf);
   // Start editor process
-  if (CreateProcessW(NULL,              // app name
+  if (CreateProcessW(nullptr,              // app name
                     wbuf,               // command to exec
-                    NULL,               // secure attribs
-                    NULL,               // thread secure attribs
+                    nullptr,               // secure attribs
+                    nullptr,               // thread secure attribs
                     FALSE,              // handle inheritance
                     0,                  // creation flags
-                    NULL,               // environ block
-                    NULL,               // current dir
+                    nullptr,               // environ block
+                    nullptr,               // current dir
                     &sinfo,             // startup info
                     &pinfo_) == 0 ) {   // process info
     fl_alert("CreateProcess() failed to start '%s': %s",
@@ -490,7 +490,7 @@ int ExternalCodeEditor::start_editor(const char *editor_cmd,
   }
   if ( L_editors_open++ == 0 )  // first editor? start timers
     { start_update_timer(); }
-  if ( G_debug )
+  if ( Fluid.debug_external_editor )
     printf("--- EDITOR STARTED: pid_=%ld #open=%d\n",
            (long)pinfo_.dwProcessId, L_editors_open);
   return 0;
@@ -512,7 +512,7 @@ void ExternalCodeEditor::reap_cleanup() {
 }
 
 // [Public] Try to reap external editor process
-// If 'pid_reaped' not NULL, returns PID of reaped editor.
+// If 'pid_reaped' not nullptr, returns PID of reaped editor.
 // Returns:
 //   -2 -- editor not open
 //   -1 -- WaitForSingleObject() failed (get_ms_errmsg() has reason)
@@ -534,7 +534,7 @@ int ExternalCodeEditor::reap_editor(DWORD *pid_reaped) {
       DWORD wpid = pinfo_.dwProcessId;      // save pid
       reap_cleanup();                       // clears pinfo_
       if ( pid_reaped ) *pid_reaped = wpid; // return pid to caller
-      if ( G_debug ) printf("*** EDITOR REAPED: pid=%ld #open=%d\n",
+      if ( Fluid.debug_external_editor ) printf("*** EDITOR REAPED: pid=%ld #open=%d\n",
                             long(wpid), L_editors_open);
       return 1;
     }
@@ -548,7 +548,7 @@ int ExternalCodeEditor::reap_editor(DWORD *pid_reaped) {
 // [Public] Open external editor using 'editor_cmd' to edit 'code'.
 //
 // 'code' contains multiline code to be edited as a temp file.
-// 'code' can be NULL -- edits an empty file if so.
+// 'code' can be nullptr -- edits an empty file if so.
 //
 // Returns:
 //   0 if succeeds
@@ -579,7 +579,7 @@ int ExternalCodeEditor::open_editor(const char *editor_cmd,
             filename(), long(pinfo_.dwProcessId));
           return 0;
         case 1:         // process reaped, wpid is pid reaped
-          if ( G_debug )
+          if ( Fluid.debug_external_editor )
             printf("*** REAPED EXTERNAL EDITOR: PID %ld\n", long(wpid));
           break;        // fall thru to open new editor instance
       }
@@ -592,12 +592,12 @@ int ExternalCodeEditor::open_editor(const char *editor_cmd,
     return -1;  // errors were shown in dialog
   }
   if ( start_editor(editor_cmd, filename()) < 0 ) { // open file in external editor
-    if ( G_debug ) printf("Editor failed to start\n");
+    if ( Fluid.debug_external_editor ) printf("Editor failed to start\n");
     return -1;  // errors were shown in dialog
   }
   // New editor opened -- start update timer (if not already)
   if ( L_update_timer_cb && !Fl::has_timeout(L_update_timer_cb) ) {
-    if ( G_debug ) printf("--- Editor opened: STARTING UPDATE TIMER\n");
+    if ( Fluid.debug_external_editor ) printf("--- Editor opened: STARTING UPDATE TIMER\n");
     Fl::add_timeout(2.0, L_update_timer_cb);
   }
   return 0;
@@ -606,14 +606,14 @@ int ExternalCodeEditor::open_editor(const char *editor_cmd,
 // [Public/Static] Start update timer
 void ExternalCodeEditor::start_update_timer() {
   if ( !L_update_timer_cb ) return;
-  if ( G_debug ) printf("--- TIMER: STARTING UPDATES\n");
+  if ( Fluid.debug_external_editor ) printf("--- TIMER: STARTING UPDATES\n");
   Fl::add_timeout(2.0, L_update_timer_cb);
 }
 
 // [Public/Static] Stop update timer
 void ExternalCodeEditor::stop_update_timer() {
   if ( !L_update_timer_cb ) return;
-  if ( G_debug ) printf("--- TIMER: STOPPING UPDATES\n");
+  if ( Fluid.debug_external_editor ) printf("--- TIMER: STOPPING UPDATES\n");
   Fl::remove_timeout(L_update_timer_cb);
 }
 
diff --git a/fluid/tools/ExternalCodeEditor_WIN32.h b/fluid/tools/ExternalCodeEditor_WIN32.h
index 97d93e495..83c50a742 100644
--- a/fluid/tools/ExternalCodeEditor_WIN32.h
+++ b/fluid/tools/ExternalCodeEditor_WIN32.h
@@ -43,7 +43,7 @@ public:
   ExternalCodeEditor();
   ~ExternalCodeEditor();
   int is_editing();
-  int reap_editor(DWORD *pid_reaped=NULL);
+  int reap_editor(DWORD *pid_reaped=nullptr);
   void close_editor();
   const char *filename() { return filename_; }
   int open_editor(const char *editor_cmd, const char *code);
diff --git a/fluid/tools/autodoc.cxx b/fluid/tools/autodoc.cxx
index 295ab8d2f..c87b59bc2 100644
--- a/fluid/tools/autodoc.cxx
+++ b/fluid/tools/autodoc.cxx
@@ -18,11 +18,11 @@
 
 #include "tools/autodoc.h"
 
-#include "app/fluid.h"
-#include "app/project.h"
+#include "Fluid.h"
+#include "Project.h"
 #include "nodes/factory.h"
-#include "nodes/Fl_Widget_Type.h"
-#include "nodes/Fl_Window_Type.h"
+#include "nodes/Widget_Node.h"
+#include "nodes/Window_Node.h"
 #include "panels/widget_panel.h"
 #include "panels/function_panel.h"
 #include "panels/settings_panel.h"
@@ -232,7 +232,7 @@ void blend_alpha_bottom(const Fl_RGB_Image *img, int dy) {
  created in FLTK resolution, even if the screen uses a higher resolution.
 
  \param[in] filename the snapshot will be written to this file in png format
- \param[in] w draw a bounding box around all widgets in the NULL terminated list
+ \param[in] w draw a bounding box around all widgets in the nullptr terminated list
  \param[in] frame add a margin around the bounding box
  \param[in] blend add another margin around the bounding box that fades to full transparency
  \param[in] scale scale everything by this factor before saving it
@@ -342,7 +342,7 @@ int fl_snapshot(const char *filename, Fl_Widget *w1, Fl_Widget *w2,
                 const Fl_Rect &blend,
                 double scale)
 {
-  Fl_Widget *ww[3] = { w1, w2, NULL };
+  Fl_Widget *ww[3] = { w1, w2, nullptr };
   return fl_snapshot(filename, ww, frame, blend, scale);
 }
 
@@ -363,7 +363,7 @@ int fl_snapshot(const char *filename, Fl_Widget *w,
                 const Fl_Rect &blend,
                 double scale)
 {
-  Fl_Widget *ww[2] = { w, NULL };
+  Fl_Widget *ww[2] = { w, nullptr };
   return fl_snapshot(filename, ww, frame, blend, scale);
 }
 
@@ -383,27 +383,27 @@ void run_autodoc(const std::string &target_dir) {
 //  Fl::scheme("gtk+");
 
   // Create a silly project that contains all widgets that we want to document
-  new_project(false);
+  Fluid.new_project(false);
 
-  /*Fl_Type *t_func = */ add_new_widget_from_user("Function", Strategy::AS_LAST_CHILD, false);
-  Fl_Window_Type *t_win = (Fl_Window_Type*)add_new_widget_from_user("Fl_Window", Strategy::AS_LAST_CHILD, false);
+  /*Node *t_func = */ add_new_widget_from_user("Function", Strategy::AS_LAST_CHILD, false);
+  Window_Node *t_win = (Window_Node*)add_new_widget_from_user("Fl_Window", Strategy::AS_LAST_CHILD, false);
   t_win->label("My Main Window");
-  Fl_Widget_Type *t_grp = (Fl_Widget_Type*)add_new_widget_from_user("Fl_Group", Strategy::AS_LAST_CHILD, false);
+  Widget_Node *t_grp = (Widget_Node*)add_new_widget_from_user("Fl_Group", Strategy::AS_LAST_CHILD, false);
   t_grp->public_ = 0;
-  Fl_Widget_Type *t_btn = (Fl_Widget_Type*)add_new_widget_from_user("Fl_Button", Strategy::AS_LAST_CHILD, false);
+  Widget_Node *t_btn = (Widget_Node*)add_new_widget_from_user("Fl_Button", Strategy::AS_LAST_CHILD, false);
   t_btn->comment("Don't press this button!");
   t_btn->name("emergency_btn");
   ((Fl_Button*)t_btn->o)->shortcut(FL_COMMAND|'g');
-  Fl_Type *t_sldr = add_new_widget_from_user("Fl_Slider", Strategy::AS_LAST_CHILD, false);
-  Fl_Type *t_inp = add_new_widget_from_user("Fl_Input", Strategy::AS_LAST_CHILD, false);
-  Fl_Type *t_flx = add_new_widget_from_user("Fl_Flex", Strategy::AS_LAST_CHILD, false);
-  Fl_Type *t_flxc = add_new_widget_from_user("Fl_Button", Strategy::AS_LAST_CHILD, false);
+  Node *t_sldr = add_new_widget_from_user("Fl_Slider", Strategy::AS_LAST_CHILD, false);
+  Node *t_inp = add_new_widget_from_user("Fl_Input", Strategy::AS_LAST_CHILD, false);
+  Node *t_flx = add_new_widget_from_user("Fl_Flex", Strategy::AS_LAST_CHILD, false);
+  Node *t_flxc = add_new_widget_from_user("Fl_Button", Strategy::AS_LAST_CHILD, false);
   select_only(t_grp);
-  Fl_Type *t_grd = add_new_widget_from_user("Fl_Grid", Strategy::AS_LAST_CHILD, false);
-  Fl_Type *t_grdc = add_new_widget_from_user("Fl_Button", Strategy::AS_LAST_CHILD, false);
+  Node *t_grd = add_new_widget_from_user("Fl_Grid", Strategy::AS_LAST_CHILD, false);
+  Node *t_grdc = add_new_widget_from_user("Fl_Button", Strategy::AS_LAST_CHILD, false);
 
   widget_browser->rebuild();
-  g_project.update_settings_dialog();
+  Fluid.proj.update_settings_dialog();
 
   // TODO: FLUID overview
 
@@ -417,9 +417,9 @@ void run_autodoc(const std::string &target_dir) {
   // explain menubar?
   // explain widget browser
   // explain widget browser entry
-  main_window->size(350, 320);
-  fl_snapshot((target_dir + "main_window.png").c_str(), main_window, win_margin, win_blend);
-  fl_snapshot((target_dir + "main_menubar.png").c_str(), main_menubar, row_margin, row_blend);
+  Fluid.main_window->size(350, 320);
+  fl_snapshot((target_dir + "Fluid.main_window.png").c_str(), Fluid.main_window, win_margin, win_blend);
+  fl_snapshot((target_dir + "main_menubar.png").c_str(), Fluid.main_menubar, row_margin, row_blend);
   fl_snapshot((target_dir + "main_browser.png").c_str(), widget_browser, FL_SNAP_AREA_CLEAR,
               Fl_Rect(0, 30, FL_SNAP_TO_WINDOW, 100), row_blend, 2.0);
 
@@ -453,7 +453,7 @@ void run_autodoc(const std::string &target_dir) {
   codeview_panel->show();
   Fl::wait(0.2);
   Fl::flush();
-  update_codeview_cb(NULL, NULL); // must be visible on screen for this to work
+  update_codeview_cb(nullptr, nullptr); // must be visible on screen for this to work
   cv_tab->value(cv_source_tab);
   codeview_panel->redraw();
   Fl::flush();
@@ -487,41 +487,41 @@ void run_autodoc(const std::string &target_dir) {
   // ---- dialog types
   // list and show all non-widget types and their respective dialog boxes
 
-  // -- ID_Function
+  // -- Type::Function
   Fl_Window *adoc_function_panel = make_function_panel();
   f_name_input->value("count_trees(const char *forest_name)");
   f_return_type_input->value("unsigned int");
   fl_snapshot((target_dir + "function_panel.png").c_str(), adoc_function_panel, win_margin, win_blend);
   adoc_function_panel->hide();
 
-  // -- ID_Code
+  // -- Type::Code
   Fl_Window *adoc_code_panel = make_code_panel();
   code_input->buffer()->text("// increment user count\nif (new_user) {\n  user_count++;\n}\n");
   fl_snapshot((target_dir + "code_panel.png").c_str(), adoc_code_panel, win_margin, win_blend);
   adoc_code_panel->hide();
 
-  // -- ID_CodeBlock
+  // -- Type::CodeBlock
   Fl_Window *adoc_codeblock_panel = make_codeblock_panel();
   code_before_input->value("if (test())");
   code_after_input->value("// test widgets added...");
   fl_snapshot((target_dir + "codeblock_panel.png").c_str(), adoc_codeblock_panel, win_margin, win_blend);
   adoc_codeblock_panel->hide();
 
-  // -- ID_Decl
+  // -- Type::Decl
   Fl_Window *adoc_decl_panel = make_decl_panel();
   decl_class_choice->hide();
   decl_input->buffer()->text("const char *damage = \"'tis but a scratch\";");
   fl_snapshot((target_dir + "decl_panel.png").c_str(), adoc_decl_panel, win_margin, win_blend);
   adoc_decl_panel->hide();
 
-  // -- ID_DeclBlock
+  // -- Type::DeclBlock
   Fl_Window *adoc_declblock_panel = make_declblock_panel();
   declblock_before_input->value("#ifdef NDEBUG");
   declblock_after_input->value("#endif // NDEBUG");
   fl_snapshot((target_dir + "declblock_panel.png").c_str(), adoc_declblock_panel, win_margin, win_blend);
   adoc_declblock_panel->hide();
 
-  // -- ID_Class
+  // -- Type::Class
   Fl_Window *adoc_class_panel = make_class_panel();
   decl_class_choice->hide();
   c_name_input->value("Zoo_Giraffe");
@@ -529,15 +529,15 @@ void run_autodoc(const std::string &target_dir) {
   fl_snapshot((target_dir + "class_panel.png").c_str(), adoc_class_panel, win_margin, win_blend);
   adoc_class_panel->hide();
 
-  // -- ID_Widget_Class is handled like Fl_Window_Type
+  // -- Type::Widget_Class is handled like Window_Node
 
-  // -- ID_Comment
+  // -- Type::Comment
   Fl_Window *adoc_comment_panel = make_comment_panel();
   comment_input->buffer()->text("Make sure that the giraffe gets enough hay,\nbut the monkey can't reach it.");
   fl_snapshot((target_dir + "comment_panel.png").c_str(), adoc_comment_panel, win_margin, win_blend);
   adoc_comment_panel->hide();
 
-  // -- ID_Data
+  // -- Type::Data
   Fl_Window *adoc_data_panel = make_data_panel();
   data_class_choice->hide();
   data_input->value("emulated_ROM");
diff --git a/fluid/tools/autodoc.h b/fluid/tools/autodoc.h
index 33b0bd6fc..136a7e119 100644
--- a/fluid/tools/autodoc.h
+++ b/fluid/tools/autodoc.h
@@ -1,5 +1,5 @@
 //
-// Widget snapshot header-only file for the Fast Light Tool Kit (FLTK).
+// Self-generate snapshots of user interface for FLUID documentation.
 //
 // Copyright 2023-2025 by Bill Spitzak and others.
 //
diff --git a/fluid/tools/filename.cxx b/fluid/tools/filename.cxx
index bbd749ce1..a5d6e22b3 100644
--- a/fluid/tools/filename.cxx
+++ b/fluid/tools/filename.cxx
@@ -1,7 +1,7 @@
 //
-// Filename expansion routines for the Fast Light Tool Kit (FLTK).
+// Filename handling code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2023 by Bill Spitzak and others.
+// Copyright 1998-2025 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -95,3 +95,31 @@ std::string fl_filename_shortened(const std::string &filename, int max_chars) {
     return homed_filename;
   }
 }
+
+/**
+ Make sure that a path name ends with a forward slash.
+ \param[in] str directory or path name
+ \return a new string, ending with a '/'
+ */
+std::string fld::end_with_slash(const std::string &str) {
+  char last = str[str.size()-1];
+  if (last !='/' && last != '\\')
+    return str + "/";
+  else
+    return str;
+}
+
+/**
+ Replace Windows '\\' directory separator with UNix '/' separators.
+ \param[in] fn a file path in Unix or Windows format
+ \return a copy of the file path in Unix format.
+ */
+std::string fld::fix_separators(const std::string &fn) {
+  std::string ret = fn;
+  for (size_t i=0; i<ret.size(); ++i) {
+    if (ret[i] == '\\') {
+      ret[i] = '/';
+    }
+  }
+  return ret;
+}
diff --git a/fluid/tools/filename.h b/fluid/tools/filename.h
index 13488d399..3a4359633 100644
--- a/fluid/tools/filename.h
+++ b/fluid/tools/filename.h
@@ -1,5 +1,5 @@
 /*
- * Filename header file for the Fast Light Tool Kit (FLTK).
+ * Filename handling header file for the Fast Light Tool Kit (FLTK).
  *
  * Copyright 1998-2025 by Bill Spitzak and others.
  *
@@ -27,7 +27,8 @@ std::string fl_filename_shortened(const std::string &filename, int maxchars);
 
 namespace fld {
 
-using filename = std::string;
+extern std::string end_with_slash(const std::string &fn);
+extern std::string fix_separators(const std::string &fn);
 
 } // namespace fld