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py/builtinhelp: Implement help('modules') to list available modules.
This is how CPython does it, and it's very useful to help users discover the available modules for a given port, especially built-in and frozen modules. The function does not list modules that are in the filesystem because this would require a fair bit of work to do correctly, and is very port specific (depending on the filesystem).
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‎py/builtinhelp.c‎

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@@ -25,8 +25,10 @@
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*/
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#include <stdio.h>
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#include <string.h>
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#include "py/builtin.h"
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#include "py/objmodule.h"
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#if MICROPY_PY_BUILTINS_HELP
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@@ -53,7 +55,87 @@ STATIC void mp_help_print_info_about_object(mp_obj_t name_o, mp_obj_t value) {
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mp_print_str(MP_PYTHON_PRINTER, "\n");
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}
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#if MICROPY_PY_BUILTINS_HELP_MODULES
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STATIC void mp_help_add_from_map(mp_obj_t list, const mp_map_t *map) {
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for (size_t i = 0; i < map->alloc; i++) {
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if (MP_MAP_SLOT_IS_FILLED(map, i)) {
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mp_obj_list_append(list, map->table[i].key);
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}
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}
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}
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#if MICROPY_MODULE_FROZEN
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STATIC void mp_help_add_from_names(mp_obj_t list, const char *name) {
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while (*name) {
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size_t l = strlen(name);
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// name should end in '.py' and we strip it off
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mp_obj_list_append(list, mp_obj_new_str(name, l - 3, false));
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name += l + 1;
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}
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}
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#endif
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STATIC void mp_help_print_modules(void) {
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mp_obj_t list = mp_obj_new_list(0, NULL);
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mp_help_add_from_map(list, &mp_builtin_module_map);
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#if MICROPY_MODULE_WEAK_LINKS
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mp_help_add_from_map(list, &mp_builtin_module_weak_links_map);
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#endif
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#if MICROPY_MODULE_FROZEN_STR
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extern const char mp_frozen_str_names[];
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mp_help_add_from_names(list, mp_frozen_str_names);
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#endif
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#if MICROPY_MODULE_FROZEN_MPY
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extern const char mp_frozen_mpy_names[];
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mp_help_add_from_names(list, mp_frozen_mpy_names);
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#endif
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// sort the list so it's printed in alphabetical order
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mp_obj_list_sort(1, &list, (mp_map_t*)&mp_const_empty_map);
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// print the list of modules in a column-first order
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#define NUM_COLUMNS (4)
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#define COLUMN_WIDTH (18)
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mp_uint_t len;
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mp_obj_t *items;
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mp_obj_list_get(list, &len, &items);
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unsigned int num_rows = (len + NUM_COLUMNS - 1) / NUM_COLUMNS;
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for (unsigned int i = 0; i < num_rows; ++i) {
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unsigned int j = i;
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for (;;) {
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int l = mp_print_str(MP_PYTHON_PRINTER, mp_obj_str_get_str(items[j]));
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j += num_rows;
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if (j >= len) {
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break;
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}
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int gap = COLUMN_WIDTH - l;
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while (gap < 1) {
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gap += COLUMN_WIDTH;
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}
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while (gap--) {
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mp_print_str(MP_PYTHON_PRINTER, " ");
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}
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}
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mp_print_str(MP_PYTHON_PRINTER, "\n");
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}
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// let the user know there may be other modules available from the filesystem
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mp_print_str(MP_PYTHON_PRINTER, "Plus any modules on the filesystem\n");
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}
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#endif
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STATIC void mp_help_print_obj(const mp_obj_t obj) {
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#if MICROPY_PY_BUILTINS_HELP_MODULES
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if (obj == MP_OBJ_NEW_QSTR(MP_QSTR_modules)) {
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mp_help_print_modules();
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return;
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}
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#endif
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// try to print something sensible about the given object
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mp_print_str(MP_PYTHON_PRINTER, "object ");
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mp_obj_print(obj, PRINT_STR);

‎py/mpconfig.h‎

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Original file line numberDiff line numberDiff line change
@@ -770,6 +770,11 @@ typedef double mp_float_t;
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#define MICROPY_PY_BUILTINS_HELP_TEXT mp_help_default_text
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#endif
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// Add the ability to list the available modules when executing help('modules')
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#ifndef MICROPY_PY_BUILTINS_HELP_MODULES
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#define MICROPY_PY_BUILTINS_HELP_MODULES (0)
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#endif
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// Whether to set __file__ for imported modules
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#ifndef MICROPY_PY___FILE__
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#define MICROPY_PY___FILE__ (1)

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