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`.

1 files changed, 136 insertions, 0 deletions

diff --git a/fluid/app/args.cxx b/fluid/app/args.cxx
new file mode 100644
index 000000000..b9d958e8c
--- /dev/null
+++ b/fluid/app/args.cxx
@@ -0,0 +1,136 @@
+//
+// Command Line Arguments Handling code for the Fast Light Tool Kit (FLTK).
+//
+// 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
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+#include "app/args.h"
+
+#include "Fluid.h"
+
+#include <FL/Fl.H>
+#include <FL/filename.H>
+#include <FL/fl_ask.H>
+
+using namespace fld;
+using namespace fld::app;
+
+/**
+ Load args from command line into variables.
+
+ \param[in] argc number of arguments in the list
+ \param[in] argv pointer to an array of arguments
+ \return 0 if the args were handled successfully, -1 if there was an error
+    and the usage message was shown.
+ */
+int Args::load(int argc,char **argv) {
+  int i = 1;
+  Fl::args_to_utf8(argc, argv); // for MSYS2/MinGW
+  if (   (Fl::args(argc,argv,i,arg_cb) == 0)     // unsupported argument found
+      || (Fluid.batch_mode && (i != argc-1))        // .fl filename missing
+      || (!Fluid.batch_mode && (i < argc-1))        // more than one filename found
+      || (argv[i] && (argv[i][0] == '-'))) {  // unknown option
+    static const char *msg =
+    "usage: %s <switches> name.fl\n"
+    " -u : update .fl file and exit (may be combined with '-c' or '-cs')\n"
+    " -c : write .cxx and .h and exit\n"
+    " -cs : write .cxx and .h and strings and exit\n"
+    " -o <name> : .cxx output filename, or extension if <name> starts with '.'\n"
+    " -h <name> : .h output filename, or extension if <name> starts with '.'\n"
+    " --help : brief usage information\n"
+    " --version, -v : print fluid version number\n"
+    " -d : enable internal debugging\n";
+    const char *app_name = nullptr;
+    if ( (argc > 0) && argv[0] && argv[0][0] )
+      app_name = fl_filename_name(argv[0]);
+    if ( !app_name || !app_name[0])
+      app_name = "fluid";
+#ifdef _MSC_VER
+    // TODO: if this is fluid-cmd, use stderr and not fl_message
+    fl_message(msg, app_name);
+#else
+    fprintf(stderr, msg, app_name);
+#endif
+    return -1;
+  }
+  return i;
+}
+
+
+int Args::arg_cb(int argc, char** argv, int& i) {
+  return Fluid.args.arg(argc, argv, i);
+}
+
+
+/**
+ Handle command line arguments.
+ \param[in] argc number of arguments in the list
+ \param[in] argv pointer to an array of arguments
+ \param[inout] i current argument index
+ \return number of arguments used; if 0, the argument is not supported
+ */
+int Args::arg(int argc, char** argv, int& i) {
+  if (argv[i][0] != '-')
+    return 0;
+  if (argv[i][1] == 'd' && !argv[i][2]) {
+    Fluid.debug_external_editor=1;
+    i++; return 1;
+  }
+  if (argv[i][1] == 'u' && !argv[i][2]) {
+    update_file++;
+    Fluid.batch_mode++;
+    i++; return 1;
+  }
+  if (argv[i][1] == 'c' && !argv[i][2]) {
+    compile_file++;
+    Fluid.batch_mode++;
+    i++; return 1;
+  }
+  if ((strcmp(argv[i], "-v")==0) || (strcmp(argv[i], "--version")==0)) {
+    show_version = 1;
+    i++; return 1;
+  }
+  if (argv[i][1] == 'c' && argv[i][2] == 's' && !argv[i][3]) {
+    compile_file++;
+    compile_strings++;
+    Fluid.batch_mode++;
+    i++; return 1;
+  }
+  if (argv[i][1] == 'o' && !argv[i][2] && i+1 < argc) {
+    code_filename = argv[i+1];
+    Fluid.batch_mode++;
+    i += 2; return 2;
+  }
+#ifndef NDEBUG
+  if ((i+1 < argc) && (strcmp(argv[i], "--autodoc") == 0)) {
+    autodoc_path = argv[i+1];
+    i += 2; return 2;
+  }
+#endif
+  if (strcmp(argv[i], "--help")==0) {
+    return 0;
+  }
+  if (argv[i][1] == 'h' && !argv[i][2]) {
+    if ( (i+1 < argc) && (argv[i+1][0] != '-') ) {
+      header_filename = argv[i+1];
+      Fluid.batch_mode++;
+      i += 2;
+      return 2;
+    } else {
+      // a lone "-h" without a filename will output the help string
+      return 0;
+    }
+  }
+  return 0;
+}
+