Re: execute incomplete commands when theres only one completion

[David Bjergaard]

If the community would benefit feel free to open a pull request and we’ll get 
the code reviewed and integrated in stumpwm proper. 

    David

> On Feb 27, 2020, at 4:53 PM, Nathan Shostek <address@hidden> wrote:
> 
> Sorry for spamming this mailing list, but I've worked out how to achieve
> the emacs-esq completions I would like to have when inputing commands
> via colon. Knowing myself, I'm probably doing something wrong, but it
> seems to work fine.
> 
> Heres the code: https://gist.github.com/szos/d7dbd8f1c9f4b7d71666bafe8621629c
> 
> Cheers,
> Nathan
> 
> Nathan Shostek writes:
> 
>> After digging further, I think the best place to make changes isnt inthese
>> functions, but rather in get-completion-preview-list. Does this sound 
>> correct?
>> 
>> Thanks,
>> Nathan s
>> 
>> Responding to: 
>> 
>>> Hello,
>>> 
>>> When Emacs is accepting input via M-x one can forego writing the whole 
>>> command
>>> due to the way emacs completes it. While I'm not skilled enough to implement
>>> emacs style completion, I do think it would be nice to be able to complete
>>> incomplete commands when there is only one possible completion. I'm putting 
>>> this
>>> here instead of in a github pull request because, in all truthfulness, 
>>> github
>>> forking and pull-requesting confuses me, and someone told me I could also 
>>> submit my contributions throught this mailing list. 
>>> 
>>> I've modified the functions eval-command and call-interactively to have an 
>>> additional optional argument called auto-complete, which when true retries
>>> completion before throwing an error. I'm not sure if this is the right way
>>> to get the behavior I want, but it works. If theres a better way to do this
>>> I'll gladly try to implement it. 
>>> 
>>> Apologies for the length of this email; I figured it was better to include 
>>> every
>>> function than just the small bits i changed, but if its not let me know and 
>>> I'll
>>> do it differently in the future.
>>> 
>>> Cheers,
>>> Nathan
>>> 
>>> Heres the code:
>>> 
>>> (defun call-interactively (command &optional (input "") auto-complete)
>>>  "Parse the command's arguments from input given the command's
>>> argument specifications then execute it. Returns a string or nil if
>>> user aborted."
>>>  (declare (type (or string symbol) command)
>>>           (type (or string argument-line) input))
>>>  ;; Catch parse errors
>>>  (catch 'error
>>>    (let* ((arg-line (if (stringp input)
>>>                         (make-argument-line :string input
>>>                                             :start 0)
>>>                         input))
>>>           (cmd-data (or (get-command-structure command)
>>>             (and auto-complete
>>>                  (let ((comp (input-find-completions command 
>>> (all-commands))))
>>>                (when (and comp (= 1 (length comp)))
>>>                  (get-command-structure (car comp)))))
>>>             (throw 'error (format nil "Command '~a' not found." command))))
>>>           (arg-specs (command-args cmd-data))
>>>           (args (loop for spec in arg-specs
>>>               collect (let* ((type (if (listp spec)
>>>                        (first spec)
>>>                        spec))
>>>                      (prompt (when (listp spec)
>>>                        (second spec)))
>>>                      (fn (gethash type *command-type-hash*)))
>>>                 (unless fn
>>>                   (throw 'error (format nil "Bad argument type: ~s" type)))
>>>                 ;; If the prompt is NIL then it's
>>>                 ;; considered an optional argument and
>>>                 ;; we shouldn't prompt for it if the
>>>                 ;; arg line is empty.
>>>                 (if (and (null prompt)
>>>                      (argument-line-end-p arg-line))
>>>                     (loop-finish)
>>>                     (funcall fn arg-line prompt))))))
>>>      ;; Did the whole string get parsed?
>>>      (unless (or (argument-line-end-p arg-line)
>>>                  (position-if 'alphanumericp (argument-line-string 
>>> arg-line) :start (argument-line-start arg-line)))
>>>        (throw 'error (format nil "Trailing garbage: ~{~A~^ ~}" (subseq 
>>> (argument-line-string arg-line)
>>>                                                                        
>>> (argument-line-start arg-line)))))
>>>      ;; Success
>>>      (prog1
>>>          (apply (command-name cmd-data) args)
>>>        (setf *last-command* command)))))
>>> 
>>> (defun eval-command (cmd &optional interactivep auto-complete)
>>>  "exec cmd and echo the result."
>>>  (labels ((parse-and-run-command (input)
>>>             (let* ((arg-line (make-argument-line :string input
>>>                                                  :start 0))
>>>                    (cmd (argument-pop arg-line)))
>>>               (let ((*interactivep* interactivep))
>>>                 (call-interactively cmd arg-line auto-complete)))))
>>>    (multiple-value-bind (result error-p)
>>>        ;; this fancy footwork lets us grab the backtrace from where the
>>>        ;; error actually happened.
>>>        (restart-case
>>>            (handler-bind
>>>                ((error (lambda (c)
>>>              (invoke-restart 'eval-command-error
>>>                      (format nil "^B^1*Error In Command '^b~a^B': ^n~A~a"
>>>                          cmd c (if *show-command-backtrace*
>>>                                (backtrace-string) ""))))))
>>>              (parse-and-run-command cmd))
>>>          (eval-command-error (err-text)
>>>            :interactive (lambda () nil)
>>>            (values err-text t)))
>>>      ;; interactive commands update the modeline
>>>      (update-all-mode-lines)
>>>      (cond ((stringp result)
>>>             (if error-p
>>>                 (message-no-timeout "~a" result)
>>>                 (message "~a" result)))
>>>            ((eq result :abort)
>>>             (unless *suppress-abort-messages*
>>>               (message "Abort.")))))))
>>> 
>>> (defcommand colon (&optional initial-input) (:rest)
>>>  "Read a command from the user. @var{initial-text} is optional. When
>>> supplied, the text will appear in the prompt.
>>> 
>>> String arguments with spaces may be passed to the command by
>>> delimiting them with double quotes. A backslash can be used to escape
>>> double quotes or backslashes inside the string. This does not apply to
>>> commands taking :REST or :SHELL type arguments."
>>>  (let ((cmd (completing-read (current-screen) ": " (all-commands) 
>>> :initial-input (or initial-input ""))))
>>>    (unless cmd
>>>      (throw 'error :abort))
>>>    (when (plusp (length cmd))
>>>      (eval-command cmd t t))))
> 
>