modsys: Add sys.print_exception(exc, file=sys.stdout) function.

The function is modeled after traceback.print_exception(), but unbloated,
and put into existing module to save overhead on adding another module.
Compliant traceback.print_exception() is intended to be implemented in
micropython-lib in terms of sys.print_exception().

This change required refactoring mp_obj_print_exception() to take pfenv_t
interface arguments.

Addresses #751.

3 files changed, 7 insertions, 4 deletions

diff --git a/stmhal/extint.c b/stmhal/extint.c
index 4fab7c5f2..a67af65b0 100644
--- a/stmhal/extint.c
+++ b/stmhal/extint.c
@@ -37,6 +37,7 @@
 #include "gc.h"
 #include "obj.h"
 #include "runtime.h"
+#include "pfenv.h"
 
 #include "pin.h"
 #include "extint.h"
@@ -373,7 +374,7 @@ void Handle_EXTI_Irq(uint32_t line) {
                     v->callback_obj = mp_const_none;
                     extint_disable(line);
                     printf("Uncaught exception in ExtInt interrupt handler line %lu\n", line);
-                    mp_obj_print_exception((mp_obj_t)nlr.ret_val);
+                    mp_obj_print_exception(printf_wrapper, NULL, (mp_obj_t)nlr.ret_val);
                 }
                 gc_unlock();
             }
diff --git a/stmhal/pyexec.c b/stmhal/pyexec.c
index 36a496aa1..d62b2a373 100644
--- a/stmhal/pyexec.c
+++ b/stmhal/pyexec.c
@@ -48,6 +48,7 @@
 #include "pyexec.h"
 #include "pybstdio.h"
 #include "genhdr/py-version.h"
+#include "pfenv.h"
 
 pyexec_mode_kind_t pyexec_mode_kind = PYEXEC_MODE_FRIENDLY_REPL;
 STATIC bool repl_display_debugging_info = 0;
@@ -87,7 +88,7 @@ STATIC int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_ki
         if (exec_flags & EXEC_FLAG_PRINT_EOF) {
             stdout_tx_strn("\x04", 1);
         }
-        mp_obj_print_exception(module_fun);
+        mp_obj_print_exception(printf_wrapper, NULL, module_fun);
         goto finish;
     }
 
@@ -116,7 +117,7 @@ STATIC int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_ki
             // at the moment, the value of SystemExit is unused
             ret = PYEXEC_FORCED_EXIT;
         } else {
-            mp_obj_print_exception((mp_obj_t)nlr.ret_val);
+            mp_obj_print_exception(printf_wrapper, NULL, (mp_obj_t)nlr.ret_val);
             ret = 0;
         }
     }
diff --git a/stmhal/timer.c b/stmhal/timer.c
index 5c99d51f1..e95fb5f9e 100644
--- a/stmhal/timer.c
+++ b/stmhal/timer.c
@@ -42,6 +42,7 @@
 #include "timer.h"
 #include "servo.h"
 #include "pin.h"
+#include "pfenv.h"
 
 /// \moduleref pyb
 /// \class Timer - periodically call a function
@@ -1245,7 +1246,7 @@ STATIC void timer_handle_irq_channel(pyb_timer_obj_t *tim, uint8_t channel, mp_o
                     } else {
                         printf("uncaught exception in Timer(%u) channel %u interrupt handler\n", tim->tim_id, channel);
                     }
-                    mp_obj_print_exception((mp_obj_t)nlr.ret_val);
+                    mp_obj_print_exception(printf_wrapper, NULL, (mp_obj_t)nlr.ret_val);
                 }
                 gc_unlock();
             }