py: Add execfile function (from Python 2); enable in stmhal port.

Adds just 60 bytes to stmhal binary.  Addresses issue #362.

py/builtin.h

@@ -41,6 +41,7 @@ MP_DECLARE_CONST_FUN_OBJ(mp_builtin_dir_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_divmod_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_eval_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_exec_obj);
+MP_DECLARE_CONST_FUN_OBJ(mp_builtin_execfile_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_getattr_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_globals_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_hasattr_obj);

py/builtinevex.c

@@ -137,7 +137,14 @@ STATIC mp_obj_t eval_exec_helper(mp_uint_t n_args, const mp_obj_t *args, mp_pars
     const char *str = mp_obj_str_get_data(args[0], &str_len);
 
     // create the lexer
-    mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_string_gt_, str, str_len, 0);
+    // MP_PARSE_SINGLE_INPUT is used to indicate a file input
+    mp_lexer_t *lex;
+    if (MICROPY_PY_BUILTINS_EXECFILE && parse_input_kind == MP_PARSE_SINGLE_INPUT) {
+        lex = mp_lexer_new_from_file(str);
+        parse_input_kind = MP_PARSE_FILE_INPUT;
+    } else {
+        lex = mp_lexer_new_from_str_len(MP_QSTR__lt_string_gt_, str, str_len, 0);
+    }
 
     return mp_parse_compile_execute(lex, parse_input_kind, globals, locals);
 }
@@ -151,3 +158,11 @@ STATIC mp_obj_t mp_builtin_exec(mp_uint_t n_args, const mp_obj_t *args) {
     return eval_exec_helper(n_args, args, MP_PARSE_FILE_INPUT);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_exec_obj, 1, 3, mp_builtin_exec);
+
+#if MICROPY_PY_BUILTINS_EXECFILE
+STATIC mp_obj_t mp_builtin_execfile(mp_uint_t n_args, const mp_obj_t *args) {
+    // MP_PARSE_SINGLE_INPUT is used to indicate a file input
+    return eval_exec_helper(n_args, args, MP_PARSE_SINGLE_INPUT);
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_execfile_obj, 1, 3, mp_builtin_execfile);
+#endif

py/modbuiltins.c

@@ -627,6 +627,9 @@ STATIC const mp_map_elem_t mp_module_builtins_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_divmod), (mp_obj_t)&mp_builtin_divmod_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_eval), (mp_obj_t)&mp_builtin_eval_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_exec), (mp_obj_t)&mp_builtin_exec_obj },
+#if MICROPY_PY_BUILTINS_EXECFILE
+    { MP_OBJ_NEW_QSTR(MP_QSTR_execfile), (mp_obj_t)&mp_builtin_execfile_obj },
+#endif
     { MP_OBJ_NEW_QSTR(MP_QSTR_getattr), (mp_obj_t)&mp_builtin_getattr_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_globals), (mp_obj_t)&mp_builtin_globals_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_hasattr), (mp_obj_t)&mp_builtin_hasattr_obj },

py/mpconfig.h

@@ -340,6 +340,11 @@ typedef double mp_float_t;
 #define MICROPY_PY_BUILTINS_COMPILE (0)
 #endif
 
+// Whether to support the Python 2 execfile function
+#ifndef MICROPY_PY_BUILTINS_EXECFILE
+#define MICROPY_PY_BUILTINS_EXECFILE (0)
+#endif
+
 // Whether to set __file__ for imported modules
 #ifndef MICROPY_PY___FILE__
 #define MICROPY_PY___FILE__ (1)

py/qstrdefs.h

@@ -167,6 +167,9 @@ Q(divmod)
 Q(enumerate)
 Q(eval)
 Q(exec)
+#if MICROPY_PY_BUILTINS_EXECFILE
+Q(execfile)
+#endif
 Q(filter)
 #if MICROPY_PY_BUILTINS_FLOAT
 Q(float)

stmhal/mpconfigport.h

@@ -54,6 +54,7 @@
 #define MICROPY_PY_BUILTINS_STR_UNICODE (1)
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (1)
 #define MICROPY_PY_BUILTINS_FROZENSET (1)
+#define MICROPY_PY_BUILTINS_EXECFILE (1)
 #define MICROPY_PY_SYS_EXIT         (1)
 #define MICROPY_PY_SYS_STDFILES     (1)
 #define MICROPY_PY_CMATH            (1)