py: Add builtin help function to core, with default help msg.

This builtin is configured using MICROPY_PY_BUILTINS_HELP, and is disabled
by default.

1 files changed, 98 insertions, 0 deletions

diff --git a/py/builtinhelp.c b/py/builtinhelp.c
new file mode 100644
index 0000000000..768806bee0
--- /dev/null
+++ b/py/builtinhelp.c
@@ -0,0 +1,98 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2016 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdio.h>
+
+#include "py/builtin.h"
+
+#if MICROPY_PY_BUILTINS_HELP
+
+const char *mp_help_default_text =
+"Welcome to MicroPython!\n"
+"\n"
+"For online docs please visit http://docs.micropython.org/\n"
+"\n"
+"Control commands:\n"
+"  CTRL-A        -- on a blank line, enter raw REPL mode\n"
+"  CTRL-B        -- on a blank line, enter normal REPL mode\n"
+"  CTRL-C        -- interrupt a running program\n"
+"  CTRL-D        -- on a blank line, exit or do a soft reset\n"
+"  CTRL-E        -- on a blank line, enter paste mode\n"
+"\n"
+"For further help on a specific object, type help(obj)\n"
+;
+
+STATIC void mp_help_print_info_about_object(mp_obj_t name_o, mp_obj_t value) {
+    mp_print_str(MP_PYTHON_PRINTER, "  ");
+    mp_obj_print(name_o, PRINT_STR);
+    mp_print_str(MP_PYTHON_PRINTER, " -- ");
+    mp_obj_print(value, PRINT_STR);
+    mp_print_str(MP_PYTHON_PRINTER, "\n");
+}
+
+STATIC void mp_help_print_obj(const mp_obj_t obj) {
+    // try to print something sensible about the given object
+    mp_print_str(MP_PYTHON_PRINTER, "object ");
+    mp_obj_print(obj, PRINT_STR);
+    mp_printf(MP_PYTHON_PRINTER, " is of type %s\n", mp_obj_get_type_str(obj));
+
+    mp_map_t *map = NULL;
+    if (MP_OBJ_IS_TYPE(obj, &mp_type_module)) {
+        map = mp_obj_dict_get_map(mp_obj_module_get_globals(obj));
+    } else {
+        mp_obj_type_t *type;
+        if (MP_OBJ_IS_TYPE(obj, &mp_type_type)) {
+            type = obj;
+        } else {
+            type = mp_obj_get_type(obj);
+        }
+        if (type->locals_dict != MP_OBJ_NULL && MP_OBJ_IS_TYPE(type->locals_dict, &mp_type_dict)) {
+            map = mp_obj_dict_get_map(type->locals_dict);
+        }
+    }
+    if (map != NULL) {
+        for (uint i = 0; i < map->alloc; i++) {
+            if (map->table[i].key != MP_OBJ_NULL) {
+                mp_help_print_info_about_object(map->table[i].key, map->table[i].value);
+            }
+        }
+    }
+}
+
+STATIC mp_obj_t mp_builtin_help(size_t n_args, const mp_obj_t *args) {
+    if (n_args == 0) {
+        // print a general help message
+        mp_print_str(MP_PYTHON_PRINTER, MICROPY_PY_BUILTINS_HELP_TEXT);
+    } else {
+        // try to print something sensible about the given object
+        mp_help_print_obj(args[0]);
+    }
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_help_obj, 0, 1, mp_builtin_help);
+
+#endif // MICROPY_PY_BUILTINS_HELP