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, 10 insertions, 10 deletions

diff --git a/py/objslice.c b/py/objslice.c
index 4f3d054c6..7983864b2 100644
--- a/py/objslice.c
+++ b/py/objslice.c
@@ -38,10 +38,10 @@ typedef struct _mp_obj_ellipsis_t {
     mp_obj_base_t base;
 } mp_obj_ellipsis_t;
 
-STATIC void ellipsis_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void ellipsis_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)self_in;
     (void)kind;
-    print(env, "Ellipsis");
+    mp_print_str(print, "Ellipsis");
 }
 
 const mp_obj_type_t mp_type_ellipsis = {
@@ -66,16 +66,16 @@ typedef struct _mp_obj_slice_t {
     mp_obj_t step;
 } mp_obj_slice_t;
 
-STATIC void slice_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind) {
+STATIC void slice_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_slice_t *o = o_in;
-    print(env, "slice(");
-    mp_obj_print_helper(print, env, o->start, PRINT_REPR);
-    print(env, ", ");
-    mp_obj_print_helper(print, env, o->stop, PRINT_REPR);
-    print(env, ", ");
-    mp_obj_print_helper(print, env, o->step, PRINT_REPR);
-    print(env, ")");
+    mp_print_str(print, "slice(");
+    mp_obj_print_helper(print, o->start, PRINT_REPR);
+    mp_print_str(print, ", ");
+    mp_obj_print_helper(print, o->stop, PRINT_REPR);
+    mp_print_str(print, ", ");
+    mp_obj_print_helper(print, o->step, PRINT_REPR);
+    mp_print_str(print, ")");
 }
 
 const mp_obj_type_t mp_type_slice = {