py/objstr: Add support for the :_b/o/x specifier in str.format.

This groups non-decimal values by fours, such as bbb_bbbb_bbbb.  It also
supports `{:_d}` to use underscore for decimal numbers (grouped in threes).

Use of incorrect ":,b" is not diagnosed.

Thanks to @dpgeorge for the suggestion to reduce code size.

Signed-off-by: Jeff Epler <jepler@gmail.com>

1 files changed, 4 insertions, 7 deletions

diff --git a/py/mpprint.c b/py/mpprint.c
index 291e4145f..00a5f944c 100644
--- a/py/mpprint.c
+++ b/py/mpprint.c
@@ -58,7 +58,7 @@ int mp_print_str(const mp_print_t *print, const char *str) {
     return len;
 }
 
-int mp_print_strn(const mp_print_t *print, const char *str, size_t len, int flags, char fill, int width) {
+int mp_print_strn(const mp_print_t *print, const char *str, size_t len, unsigned int flags, char fill, int width) {
     int left_pad = 0;
     int right_pad = 0;
     int pad = width - len;
@@ -201,7 +201,7 @@ static int mp_print_int(const mp_print_t *print, mp_uint_t x, int sgn, int base,
     return len;
 }
 
-int mp_print_mp_int(const mp_print_t *print, mp_obj_t x, int base, int base_char, int flags, char fill, int width, int prec) {
+int mp_print_mp_int(const mp_print_t *print, mp_obj_t x, unsigned int base, int base_char, int flags, char fill, int width, int prec) {
     // These are the only values for "base" that are required to be supported by this
     // function, since Python only allows the user to format integers in these bases.
     // If needed this function could be generalised to handle other values.
@@ -248,10 +248,7 @@ int mp_print_mp_int(const mp_print_t *print, mp_obj_t x, int base, int base_char
     int prefix_len = prefix - prefix_buf;
     prefix = prefix_buf;
 
-    char comma = '\0';
-    if (flags & PF_FLAG_SHOW_COMMA) {
-        comma = ',';
-    }
+    char comma = flags >> PF_FLAG_SEP_POS;
 
     // The size of this buffer is rather arbitrary. If it's not large
     // enough, a dynamic one will be allocated.
@@ -340,7 +337,7 @@ int mp_print_mp_int(const mp_print_t *print, mp_obj_t x, int base, int base_char
 }
 
 #if MICROPY_PY_BUILTINS_FLOAT
-int mp_print_float(const mp_print_t *print, mp_float_t f, char fmt, int flags, char fill, int width, int prec) {
+int mp_print_float(const mp_print_t *print, mp_float_t f, char fmt, unsigned int flags, char fill, int width, int prec) {
     char buf[32];
     char sign = '\0';
     int chrs = 0;