py: Overhaul and simplify printf/pfenv mechanism.

Previous to this patch the printing mechanism was a bit of a tangled
mess.  This patch attempts to consolidate printing into one interface.

All (non-debug) printing now uses the mp_print* family of functions,
mainly mp_printf.  All these functions take an mp_print_t structure as
their first argument, and this structure defines the printing backend
through the "print_strn" function of said structure.

Printing from the uPy core can reach the platform-defined print code via
two paths: either through mp_sys_stdout_obj (defined pert port) in
conjunction with mp_stream_write; or through the mp_plat_print structure
which uses the MP_PLAT_PRINT_STRN macro to define how string are printed
on the platform.  The former is only used when MICROPY_PY_IO is defined.

With this new scheme printing is generally more efficient (less layers
to go through, less arguments to pass), and, given an mp_print_t*
structure, one can call mp_print_str for efficiency instead of
mp_printf("%s", ...).  Code size is also reduced by around 200 bytes on
Thumb2 archs.

1 files changed, 3 insertions, 3 deletions

diff --git a/py/objmodule.c b/py/objmodule.c
index 971c7f38c..84d97f494 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -33,7 +33,7 @@
 #include "py/runtime.h"
 #include "py/builtin.h"
 
-STATIC void module_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void module_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_module_t *self = self_in;
     const char *name = qstr_str(self->name);
@@ -43,12 +43,12 @@ STATIC void module_print(void (*print)(void *env, const char *fmt, ...), void *e
     // symbol to give more information about the module.
     mp_map_elem_t *elem = mp_map_lookup(&self->globals->map, MP_OBJ_NEW_QSTR(MP_QSTR___file__), MP_MAP_LOOKUP);
     if (elem != NULL) {
-        print(env, "<module '%s' from '%s'>", name, mp_obj_str_get_str(elem->value));
+        mp_printf(print, "<module '%s' from '%s'>", name, mp_obj_str_get_str(elem->value));
         return;
     }
 #endif
 
-    print(env, "<module '%s'>", name);
+    mp_printf(print, "<module '%s'>", name);
 }
 
 STATIC void module_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {