lib/mp-readline: Add emacs-style control characters for cursor movement.

Disabled by default.  Adds 108 bytes to Thumb2 arch when enabled.

lib/mp-readline/readline.c

@@ -111,12 +111,44 @@ int readline_process_char(int c) {
         } else if (c == CHAR_CTRL_A) {
             // CTRL-A with non-empty line is go-to-start-of-line
             goto home_key;
+        #if MICROPY_REPL_EMACS_KEYS
+        } else if (c == CHAR_CTRL_B) {
+            // CTRL-B with non-empty line is go-back-one-char
+            goto left_arrow_key;
+        #endif
         } else if (c == CHAR_CTRL_C) {
             // CTRL-C with non-empty line is cancel
             return c;
+        #if MICROPY_REPL_EMACS_KEYS
+        } else if (c == CHAR_CTRL_D) {
+            // CTRL-D with non-empty line is delete-at-cursor
+            goto delete_key;
+        #endif
         } else if (c == CHAR_CTRL_E) {
             // CTRL-E is go-to-end-of-line
             goto end_key;
+        #if MICROPY_REPL_EMACS_KEYS
+        } else if (c == CHAR_CTRL_F) {
+            // CTRL-F with non-empty line is go-forward-one-char
+            goto right_arrow_key;
+        } else if (c == CHAR_CTRL_K) {
+            // CTRL-K is kill from cursor to end-of-line, inclusive
+	    vstr_cut_tail_bytes(rl.line, last_line_len - rl.cursor_pos);
+	    // set redraw parameters
+	    redraw_from_cursor = true;
+        } else if (c == CHAR_CTRL_N) {
+            // CTRL-N is go to next line in history
+            goto down_arrow_key;
+        } else if (c == CHAR_CTRL_P) {
+            // CTRL-P is go to previous line in history
+            goto up_arrow_key;
+        } else if (c == CHAR_CTRL_U) {
+            // CTRL-U is kill from beginning-of-line up to cursor
+	    vstr_cut_out_bytes(rl.line, rl.orig_line_len, rl.cursor_pos - rl.orig_line_len);
+	    // set redraw parameters
+	    redraw_step_back = rl.cursor_pos - rl.orig_line_len;
+	    redraw_from_cursor = true;
+        #endif
         } else if (c == '\r') {
             // newline
             mp_hal_stdout_tx_str("\r\n");
@@ -181,6 +213,9 @@ int readline_process_char(int c) {
         } else {
             rl.escape_seq = ESEQ_NONE;
             if (c == 'A') {
+#if MICROPY_REPL_EMACS_KEYS
+up_arrow_key:
+#endif
                 // up arrow
                 if (rl.hist_cur + 1 < (int)READLINE_HIST_SIZE && MP_STATE_PORT(readline_hist)[rl.hist_cur + 1] != NULL) {
                     // increase hist num
@@ -194,6 +229,9 @@ int readline_process_char(int c) {
                     redraw_step_forward = rl.line->len - rl.orig_line_len;
                 }
             } else if (c == 'B') {
+#if MICROPY_REPL_EMACS_KEYS
+down_arrow_key:
+#endif
                 // down arrow
                 if (rl.hist_cur >= 0) {
                     // decrease hist num
@@ -209,11 +247,17 @@ int readline_process_char(int c) {
                     redraw_step_forward = rl.line->len - rl.orig_line_len;
                 }
             } else if (c == 'C') {
+#if MICROPY_REPL_EMACS_KEYS
+right_arrow_key:
+#endif
                 // right arrow
                 if (rl.cursor_pos < rl.line->len) {
                     redraw_step_forward = 1;
                 }
             } else if (c == 'D') {
+#if MICROPY_REPL_EMACS_KEYS
+left_arrow_key:
+#endif
                 // left arrow
                 if (rl.cursor_pos > rl.orig_line_len) {
                     redraw_step_back = 1;
@@ -238,7 +282,10 @@ end_key:
                 redraw_step_forward = rl.line->len - rl.cursor_pos;
             } else if (rl.escape_seq_buf[0] == '3') {
                 // delete
-                if (rl.cursor_pos >= rl.orig_line_len && rl.cursor_pos < rl.line->len) {
+#if MICROPY_REPL_EMACS_KEYS
+delete_key:
+#endif
+                if (rl.cursor_pos < rl.line->len) {
                     vstr_cut_out_bytes(rl.line, rl.cursor_pos, 1);
                     redraw_from_cursor = true;
                 }

lib/mp-readline/readline.h

@@ -29,6 +29,11 @@
 #define CHAR_CTRL_C (3)
 #define CHAR_CTRL_D (4)
 #define CHAR_CTRL_E (5)
+#define CHAR_CTRL_F (6)
+#define CHAR_CTRL_K (11)
+#define CHAR_CTRL_N (14)
+#define CHAR_CTRL_P (16)
+#define CHAR_CTRL_U (21)
 
 void readline_init0(void);
 int readline(vstr_t *line, const char *prompt);

py/mpconfig.h

@@ -303,6 +303,11 @@
 #define MICROPY_HELPER_REPL (0)
 #endif
 
+// Whether to include emacs-style readline behavior in REPL
+#ifndef MICROPY_REPL_EMACS_KEYS
+#define MICROPY_REPL_EMACS_KEYS (1)
+#endif
+
 // Whether port requires event-driven REPL functions
 #ifndef MICROPY_REPL_EVENT_DRIVEN
 #define MICROPY_REPL_EVENT_DRIVEN (0)

stmhal/mpconfigport.h

@@ -39,6 +39,7 @@
 #define MICROPY_ENABLE_FINALISER    (1)
 #define MICROPY_STACK_CHECK         (1)
 #define MICROPY_HELPER_REPL         (1)
+#define MICROPY_REPL_EMACS_KEYS     (1)
 #define MICROPY_ENABLE_SOURCE_LINE  (1)
 #define MICROPY_LONGINT_IMPL        (MICROPY_LONGINT_IMPL_MPZ)
 #define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_FLOAT)

unix/mpconfigport.h

@@ -52,6 +52,7 @@
 #define MICROPY_DEBUG_PRINTERS      (1)
 #define MICROPY_USE_READLINE_HISTORY (1)
 #define MICROPY_HELPER_REPL         (1)
+#define MICROPY_REPL_EMACS_KEYS     (1)
 #define MICROPY_HELPER_LEXER_UNIX   (1)
 #define MICROPY_ENABLE_SOURCE_LINE  (1)
 #define MICROPY_FLOAT_IMPL          (MICROPY_FLOAT_IMPL_DOUBLE)