Support `bind SEQ` to print a binding for `SEQ`

2 files changed, 37 insertions, 7 deletions

diff --git a/builtin.cpp b/builtin.cpp
index ab258acd..a8478c4f 100644
--- a/builtin.cpp
+++ b/builtin.cpp
@@ -516,23 +516,24 @@ static int get_terminfo_sequence(const wchar_t *seq, wcstring *out_seq)
     {
         return 1;
     }
+    wcstring eseq = escape_string(seq, 0);
     switch (errno)
     {
         case ENOENT:
         {
-            append_format(stderr_buffer, _(L"%ls: No key with name '%ls' found\n"), L"bind", seq);
+            append_format(stderr_buffer, _(L"%ls: No key with name '%ls' found\n"), L"bind", eseq.c_str());
             break;
         }
 
         case EILSEQ:
         {
-            append_format(stderr_buffer, _(L"%ls: Key with name '%ls' does not have any mapping\n"), L"bind", seq);
+            append_format(stderr_buffer, _(L"%ls: Key with name '%ls' does not have any mapping\n"), L"bind", eseq.c_str());
             break;
         }
 
         default:
         {
-            append_format(stderr_buffer, _(L"%ls: Unknown error trying to bind to key named '%ls'\n"), L"bind", seq);
+            append_format(stderr_buffer, _(L"%ls: Unknown error trying to bind to key named '%ls'\n"), L"bind", eseq.c_str());
             break;
         }
     }
@@ -763,8 +764,33 @@ static int builtin_bind(parser_t &parser, wchar_t **argv)
 
                 case 1:
                 {
-                    res = STATUS_BUILTIN_ERROR;
-                    append_format(stderr_buffer, _(L"%ls: Expected zero or at least two parameters, got %d\n"), argv[0], argc-woptind);
+                    wcstring seq;
+                    if (use_terminfo)
+                    {
+                        if (!get_terminfo_sequence(argv[woptind], &seq))
+                        {
+                            res = STATUS_BUILTIN_ERROR;
+                            // get_terminfo_sequence already printed the error
+                            break;
+                        }
+                    }
+                    else
+                    {
+                        seq = argv[woptind];
+                    }
+                    if (!builtin_bind_list_one(seq, bind_mode))
+                    {
+                        res = STATUS_BUILTIN_ERROR;
+                        wcstring eseq = escape_string(argv[woptind], 0);
+                        if (use_terminfo)
+                        {
+                            append_format(stderr_buffer, _(L"%ls: No binding found for key '%ls'\n"), argv[0], eseq.c_str());
+                        }
+                        else
+                        {
+                            append_format(stderr_buffer, _(L"%ls: No binding found for sequence '%ls'\n"), argv[0], eseq.c_str());
+                        }
+                    }
                     break;
                 }
 
diff --git a/doc_src/bind.txt b/doc_src/bind.txt
index 93e1f80d..599a1ec3 100644
--- a/doc_src/bind.txt
+++ b/doc_src/bind.txt
@@ -4,6 +4,7 @@
 \fish{synopsis}
 bind [(-M | --mode) MODE] [(-m | --sets-mode) NEW_MODE]
      [(-k | --key)] SEQUENCE COMMAND [COMMAND...]
+bind [(-M | --mode) MODE] [(-k | --key)] SEQUENCE
 bind (-K | --key-names) [(-a | --all)]
 bind (-f | --function-names)
 bind (-e | --erase) [(-M | --mode) MODE]
@@ -12,8 +13,7 @@ bind (-e | --erase) [(-M | --mode) MODE]
 
 \subsection bind-description Description
 
-`bind` adds a binding for the specified key sequence to the
-specified command.
+`bind` adds a binding for the specified key sequence to the specified command.
 
 SEQUENCE is the character sequence to bind to. These should be written as <a href="index.html#escapes">fish escape sequences</a>. For example, because pressing the Alt key and another character sends that character prefixed with an escape character, Alt-based key bindings can be written using the `\e` escape. For example, @key{Alt,w} can be written as `\ew`. The control character can be written in much the same way using the `\c` escape, for example @key{Control,X} (^X) can be written as `\cx`. Note that Alt-based key bindings are case sensitive and Control-based key bindings are not. This is a constraint of text-based terminals, not `fish`.
 
@@ -27,6 +27,10 @@ When `COMMAND` is a shellscript command, it is a good practice to put the actual
 
 If such a script produces output, the script needs to finish by calling `commandline -f repaint` in order to tell fish that a repaint is in order.
 
+When multiple `COMMAND`s are provided, they are all run in the specified order when the key is pressed.
+
+If no `SEQUENCE` is provided, all bindings (or just the bindings in the specified `MODE`) are printed. If `SEQUENCE` is provided without `COMMAND`, just the binding matching that sequence is printed.
+
 Key bindings are not saved between sessions by default. To save custom keybindings, edit the `fish_user_key_bindings` function and insert the appropriate `bind` statements.
 
 Key bindings may use "modes", which mimics Vi's modal input behavior. The default mode is "default", and every bind applies to a single mode. The mode can be viewed/changed with the `$fish_bind_mode` variable.