stmhal: Improve REPL control codes; improve pyboard.py script.

Improvements are:

2 ctrl-C's are now needed to truly kill running script on pyboard, so
make CDC interface allow multiple ctrl-C's through at once (ie sending
b'\x03\x03' to pyboard now counts as 2 ctrl-C's).

ctrl-C in friendly-repl can now stop multi-line input.

In raw-repl mode, use ctrl-D to indicate end of running script, and also
end of any error message.  Thus, output of raw-repl is always at least 2
ctrl-D's and it's much easier to parse.

pyboard.py is now a bit faster, handles exceptions from pyboard better
(prints them and exits with exit code 1), prints out the pyboard output
while the script is running (instead of waiting till the end), and
allows to follow the output of a previous script when run with no
arguments.

1 files changed, 45 insertions, 15 deletions

diff --git a/stmhal/pyexec.c b/stmhal/pyexec.c
index 08a5866a0..3fd797c0d 100644
--- a/stmhal/pyexec.c
+++ b/stmhal/pyexec.c
@@ -54,31 +54,47 @@
 pyexec_mode_kind_t pyexec_mode_kind = PYEXEC_MODE_FRIENDLY_REPL;
 STATIC bool repl_display_debugging_info = 0;
 
+#define EXEC_FLAG_PRINT_EOF (1)
+#define EXEC_FLAG_ALLOW_DEBUGGING (2)
+#define EXEC_FLAG_IS_REPL (4)
+
 // parses, compiles and executes the code in the lexer
 // frees the lexer before returning
-int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_kind, bool is_repl) {
+// EXEC_FLAG_PRINT_EOF prints 2 EOF chars: 1 after normal output, 1 after exception output
+// EXEC_FLAG_ALLOW_DEBUGGING allows debugging info to be printed after executing the code
+// EXEC_FLAG_IS_REPL is used for REPL inputs (flag passed on to mp_compile)
+STATIC int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_kind, int exec_flags) {
+    int ret = 0;
+
     mp_parse_error_kind_t parse_error_kind;
     mp_parse_node_t pn = mp_parse(lex, input_kind, &parse_error_kind);
     qstr source_name = mp_lexer_source_name(lex);
 
+    // check for parse error
     if (pn == MP_PARSE_NODE_NULL) {
-        // parse error
+        if (exec_flags & EXEC_FLAG_PRINT_EOF) {
+            stdout_tx_strn("\x04", 1);
+        }
         mp_parse_show_exception(lex, parse_error_kind);
         mp_lexer_free(lex);
-        return 0;
+        goto finish;
     }
 
     mp_lexer_free(lex);
 
-    mp_obj_t module_fun = mp_compile(pn, source_name, MP_EMIT_OPT_NONE, is_repl);
+    mp_obj_t module_fun = mp_compile(pn, source_name, MP_EMIT_OPT_NONE, exec_flags & EXEC_FLAG_IS_REPL);
 
+    // check for compile error
     if (mp_obj_is_exception_instance(module_fun)) {
+        if (exec_flags & EXEC_FLAG_PRINT_EOF) {
+            stdout_tx_strn("\x04", 1);
+        }
         mp_obj_print_exception(module_fun);
-        return 0;
+        goto finish;
     }
 
+    // execute code
     nlr_buf_t nlr;
-    int ret;
     uint32_t start = HAL_GetTick();
     if (nlr_push(&nlr) == 0) {
         usb_vcp_set_interrupt_char(VCP_CHAR_CTRL_C); // allow ctrl-C to interrupt us
@@ -86,10 +102,17 @@ int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_kind, boo
         usb_vcp_set_interrupt_char(VCP_CHAR_NONE); // disable interrupt
         nlr_pop();
         ret = 1;
+        if (exec_flags & EXEC_FLAG_PRINT_EOF) {
+            stdout_tx_strn("\x04", 1);
+        }
     } else {
         // uncaught exception
         // FIXME it could be that an interrupt happens just before we disable it here
         usb_vcp_set_interrupt_char(VCP_CHAR_NONE); // disable interrupt
+        // print EOF after normal output
+        if (exec_flags & EXEC_FLAG_PRINT_EOF) {
+            stdout_tx_strn("\x04", 1);
+        }
         // check for SystemExit
         if (mp_obj_is_subclass_fast(mp_obj_get_type((mp_obj_t)nlr.ret_val), &mp_type_SystemExit)) {
             // at the moment, the value of SystemExit is unused
@@ -101,7 +124,7 @@ int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_kind, boo
     }
 
     // display debugging info if wanted
-    if (is_repl && repl_display_debugging_info) {
+    if ((exec_flags & EXEC_FLAG_ALLOW_DEBUGGING) && repl_display_debugging_info) {
         uint32_t ticks = HAL_GetTick() - start; // TODO implement a function that does this properly
         printf("took %lu ms\n", ticks);
         gc_collect();
@@ -123,6 +146,11 @@ int parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t input_kind, boo
         }
     }
 
+finish:
+    if (exec_flags & EXEC_FLAG_PRINT_EOF) {
+        stdout_tx_strn("\x04", 1);
+    }
+
     return ret;
 }
 
@@ -171,16 +199,13 @@ raw_repl_reset:
 
         mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_stdin_gt_, line.buf, line.len, 0);
         if (lex == NULL) {
-            printf("MemoryError\n");
+            printf("\x04MemoryError\n\x04");
         } else {
-            int ret = parse_compile_execute(lex, MP_PARSE_FILE_INPUT, false);
+            int ret = parse_compile_execute(lex, MP_PARSE_FILE_INPUT, EXEC_FLAG_PRINT_EOF);
             if (ret & PYEXEC_FORCED_EXIT) {
                 return ret;
             }
         }
-
-        // indicate end of output with EOF character
-        stdout_tx_str("\004");
     }
 }
 
@@ -217,6 +242,7 @@ friendly_repl_reset:
     */
 
     for (;;) {
+    input_restart:
         vstr_reset(&line);
         int ret = readline(&line, ">>> ");
 
@@ -246,7 +272,11 @@ friendly_repl_reset:
         while (mp_repl_continue_with_input(vstr_str(&line))) {
             vstr_add_char(&line, '\n');
             int ret = readline(&line, "... ");
-            if (ret == VCP_CHAR_CTRL_D) {
+            if (ret == VCP_CHAR_CTRL_C) {
+                // cancel everything
+                stdout_tx_str("\r\n");
+                goto input_restart;
+            } else if (ret == VCP_CHAR_CTRL_D) {
                 // stop entering compound statement
                 break;
             }
@@ -256,7 +286,7 @@ friendly_repl_reset:
         if (lex == NULL) {
             printf("MemoryError\n");
         } else {
-            int ret = parse_compile_execute(lex, MP_PARSE_SINGLE_INPUT, true);
+            int ret = parse_compile_execute(lex, MP_PARSE_SINGLE_INPUT, EXEC_FLAG_ALLOW_DEBUGGING | EXEC_FLAG_IS_REPL);
             if (ret & PYEXEC_FORCED_EXIT) {
                 return ret;
             }
@@ -272,7 +302,7 @@ int pyexec_file(const char *filename) {
         return false;
     }
 
-    return parse_compile_execute(lex, MP_PARSE_FILE_INPUT, false);
+    return parse_compile_execute(lex, MP_PARSE_FILE_INPUT, 0);
 }
 
 mp_obj_t pyb_set_repl_info(mp_obj_t o_value) {