examples/embedding-full: Add a more full-featured embedding example.

It compiles and runs in this state, but a lot of functionality is still
missing, to be extended over the following commits.

Signed-off-by: Christian Walther <cwalther@gmx.ch>

.github/workflows/examples.yml

@@ -23,3 +23,12 @@ jobs:
       run: make -C examples/embedding -f micropython_embed.mk && make -C examples/embedding
     - name: Run
       run: ./examples/embedding/embed | grep "hello world"
+
+  embedding-full:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Build
+      run: make -C examples/embedding-full -f micropython_embed.mk submodules && make -C examples/embedding-full -f micropython_embed.mk && make -C examples/embedding-full
+    - name: Run
+      run: ./examples/embedding-full/embed

examples/embedding-full/Makefile

@@ -0,0 +1,25 @@
+# This file is part of the MicroPython project, http://micropython.org/
+# The MIT License (MIT)
+# Copyright (c) 2022-2023 Damien P. George
+#
+# This is a very simple makefile that demonstrates how to build the embed port.
+# All it needs to do is build all *.c files in the micropython_embed directory.
+# This makefile would be replaced with your custom build system.
+
+EMBED_DIR = micropython_embed
+PROG = embed
+
+CFLAGS += -I.
+CFLAGS += -I$(EMBED_DIR)
+CFLAGS += -I$(EMBED_DIR)/port
+CFLAGS += -Wall -Og -fno-common
+
+SRC += main.c mphal.c
+SRC += $(wildcard $(EMBED_DIR)/*/*.c) $(wildcard $(EMBED_DIR)/*/*/*.c)
+OBJ += $(SRC:.c=.o)
+
+$(PROG): $(OBJ)
+	$(CC) -o $@ $^
+
+clean:
+	/bin/rm -f $(OBJ) $(PROG)

examples/embedding-full/README.md

@@ -0,0 +1,41 @@
+Example of embedding MicroPython in a standalone C application (full)
+=====================================================================
+
+This directory contains a simple example of how to embed a full-featured
+version of MicroPython in an existing C application.
+See also _embedding_ for a more minimal version.
+
+A C application is represented here by the file `main.c`.  It executes two
+simple Python scripts which print things to the standard output.
+Functions used by the MicroPython core that need to be provided by the
+application are implemented in `mphal.c`.
+
+Building the example
+--------------------
+
+First build the embed port using:
+
+    $ make -f micropython_embed.mk submodules
+    $ make -f micropython_embed.mk
+
+This will generate the `micropython_embed` directory which is a self-contained
+copy of MicroPython suitable for embedding.  The .c files in this directory need
+to be compiled into your project, in whatever way your project can do that.  The
+example here uses make and a provided `Makefile`.
+
+To build the example project, based on `main.c`, use:
+
+    $ make
+
+That will create an executable called `embed` which you can run:
+
+    $ ./embed
+
+Out of tree build
+-----------------
+
+This example is set up to work out of the box, being part of the MicroPython
+tree.  Your application will be outside of this tree, but the only thing you
+need to do for that is to change `MICROPYTHON_TOP` (found in `micropython_embed.mk`)
+to point to the location of the MicroPython repository.  The MicroPython
+repository may, for example, be a git submodule in your project.

examples/embedding-full/main.c

@@ -0,0 +1,62 @@
+/* This file is part of the MicroPython project, http://micropython.org/
+ * The MIT License (MIT)
+ * Copyright (c) 2022-2023 Damien P. George
+ */
+
+#include "port/micropython_embed.h"
+#include "py/stackctrl.h"
+
+// This is example 1 script, which will be compiled and executed.
+static const char *example_1 =
+    "print('hello world!', list(x + 1 for x in range(10)), end='eol\\n')";
+
+// This is example 2 script, which will be compiled and executed.
+static const char *example_2 =
+    "for i in range(10):\n"
+    "    print('iter {:08}'.format(i))\n"
+    "\n"
+    "try:\n"
+    "    1//0\n"
+    "except Exception as er:\n"
+    "    print('caught exception', repr(er))\n"
+    "\n"
+    "import gc\n"
+    "print('run GC collect')\n"
+    "gc.collect()\n"
+    "\n"
+    "print('help(\\'modules\\'):')\n"
+    "help('modules')\n"
+    "import sys\n"
+    "help(sys)\n"
+    "\n"
+    "print('finish')\n"
+    ;
+
+// This array is the MicroPython GC heap.
+static char heap[8 * 1024];
+
+int main() {
+#if MICROPY_STACK_CHECK
+    // Set the stack limit, otherwise the default is zero and we will end up in
+    // nlr_jump_fail() immediately.
+    mp_stack_set_limit(10240);
+#endif
+    // Initialise MicroPython.
+    //
+    // Note: &stack_top below should be good enough for many cases.
+    // However, depending on environment, there might be more appropriate
+    // ways to get the stack top value.
+    // eg. pthread_get_stackaddr_np, pthread_getattr_np,
+    // __builtin_frame_address/__builtin_stack_address, etc.
+    int stack_top;
+    mp_embed_init(&heap[0], sizeof(heap), &stack_top);
+
+    // Run the example scripts (they will be compiled first).
+    mp_embed_exec_str(example_1);
+    mp_embed_exec_str(example_2);
+
+    // Deinitialise MicroPython.
+    mp_embed_deinit();
+
+    return 0;
+}

examples/embedding-full/micropython_embed.mk

@@ -0,0 +1,9 @@
+# This file is part of the MicroPython project, http://micropython.org/
+# The MIT License (MIT)
+# Copyright (c) 2022-2023 Damien P. George
+
+# Set the location of the top of the MicroPython repository.
+MICROPYTHON_TOP = ../..
+
+# Include the main makefile fragment to build the MicroPython component.
+include $(MICROPYTHON_TOP)/ports/embed/embed.mk

examples/embedding-full/mpconfigport.h

@@ -0,0 +1,32 @@
+/* This file is part of the MicroPython project, http://micropython.org/
+ * The MIT License (MIT)
+ * Copyright (c) 2022-2023 Damien P. George
+ */
+
+// Include common MicroPython embed configuration.
+#include <port/mpconfigport_common.h>
+
+// Use the same starting configuration as on most bare-metal targets.
+#define MICROPY_CONFIG_ROM_LEVEL                (MICROPY_CONFIG_ROM_LEVEL_EXTRA_FEATURES)
+
+// MicroPython configuration.
+#define MICROPY_ENABLE_COMPILER                 (1)
+#define MICROPY_ENABLE_GC                       (1)
+#define MICROPY_PY_GC                           (1)
+
+#define MICROPY_PY_SYS_PLATFORM                 "embedded"
+
+// Requires shared/readline/readline.h, don't bother as we have no input.
+#define MICROPY_PY_BUILTINS_INPUT               (0)
+
+// Can be enabled once extmod/moductypes.c is included in the build.
+#define MICROPY_PY_UCTYPES                      (0)
+
+// Can be enabled once either shared/runtime/sys_stdio_mphal.c or
+// extmod/vfs_posix_file.c is included in the build.
+#define MICROPY_PY_SYS_STDFILES                 (0)
+
+// Can be enabled if you provide an implementation of
+// mp_hal_set_interrupt_char() in mphal.c or include
+// shared/runtime/interrupt_char.c in the build.
+#define MICROPY_KBD_EXCEPTION                   (0)

examples/embedding-full/mphal.c

@@ -0,0 +1,26 @@
+/* This file is part of the MicroPython project, http://micropython.org/
+ * The MIT License (MIT)
+ * Copyright (c) 2022-2023 Damien P. George
+ */
+
+#include "py/builtin.h"
+#include "py/compile.h"
+#include "py/mperrno.h"
+
+#if !MICROPY_VFS
+
+mp_lexer_t *mp_lexer_new_from_file(qstr filename) {
+    mp_raise_OSError(MP_ENOENT);
+}
+
+mp_import_stat_t mp_import_stat(const char *path) {
+    (void)path;
+    return MP_IMPORT_STAT_NO_EXIST;
+}
+
+mp_obj_t mp_builtin_open(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs) {
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_KW(mp_builtin_open_obj, 1, mp_builtin_open);
+
+#endif

examples/embedding/README.md

@@ -1,8 +1,9 @@
-Example of embedding MicroPython in a standalone C application
-==============================================================
+Example of embedding MicroPython in a standalone C application (minimal)
+========================================================================
 
-This directory contains a simple example of how to embed MicroPython in an
-existing C application.
+This directory contains a simple example of how to embed a minimal version of
+MicroPython in an existing C application.
+See also _embedding-full_ for a more full-featured version.
 
 A C application is represented here by the file `main.c`.  It executes two
 simple Python scripts which print things to the standard output.

ports/embed/port/mphalport.h

@@ -1,2 +1,6 @@
 // Define so there's no dependency on extmod/virtpin.h
 #define mp_hal_pin_obj_t
+
+#if MICROPY_KBD_EXCEPTION
+void mp_hal_set_interrupt_char(int c);
+#endif