Re: isearch region or thing at point.

[Ergus <spacibba@aol.com>]

Hi:

I wrote this code today to do a search auto-insert text from region like
behavior.

===============================================

(defun isearch-forward-region (&optional arg)
  "Do incremental search forward for text in active region.
Like ordinary incremental search except that the text in the active
region is added to the search string initially if variable
`transient-mark-mode' is non nil.  See the command
`isearch-forward-symbol' for more information.	With a prefix
argument, search for ARGth symbol forward if ARG is positive, or
search for ARGth symbol backward if ARG is negative."
  (interactive "P")
  (isearch-forward nil 1)
  (if-let* ((bounds (and (use-region-p) ;; Region and transient non-nil
			 (string-empty-p isearch-string)
			 (region-bounds)))
	    (contiguous (= (length bounds) 1)) ;; Region is contiguous
	    (region-beg (car (car bounds)))
	    (region-end (cdr (car bounds)))
	    (region-string (and (= (count-lines region-beg region-end) 1)
				(buffer-substring-no-properties
				 region-beg region-end)))
	    (noempty (not (string-blank-p region-string))))
      (progn
	(goto-char region-beg)
	(setq mark-active nil
	      isearch--deactivated-mark t)
	(isearch-yank-string region-string)

	(when-let (count (and arg (prefix-numeric-value arg)))
	  (isearch-repeat-forward count)))

    (setq isearch-error "Invalid region for isearch")
    (isearch-push-state)
    (isearch-update)))

================================================

The problem is that when I C-x C-e, it works fine, but when
I compile it I get an error with message:

```
funcall-interactively: Symbol???s value as variable is void: bounds
```

I am pretty new using lisp, but I don't understand this behavior, Any
help, please.

The backtrace only says:

==================================================
Debugger entered--Lisp error: (void-variable bounds)
  isearch-forward-region(nil)
  funcall-interactively(isearch-forward-region nil)
  call-interactively(isearch-forward-region nil nil)
  command-execute(isearch-forward-region)
==================================================

Do I am using wrong the if-let* statement? 

Thanks in advance,
Ergus.

On Mon, Apr 29, 2019 at 10:41:28PM +0300, Juri Linkov wrote:
>>>The closest to this that I'm aware of is
>>>isearch-forward-symbol-at-point, bound to 'M-s .' by default.
>>>
>> I just made a small change in isearch.el to enable region text auto
>> insertion in transient-mark-mode. (patch attached)
>>
>> I did it as simple as I could. So please if you (or any anyone) could
>> give a look and correct/improve/expose corner cases, or suggest a better
>> implementation will be very nice.
>>
>> I don't have corner cases right now, but I just started testing it.
>>
>> So any correction/suggestion/recommendation is very appreciated.
>
>Thanks, such addition is welcome.  Currently searching the
>active region requires invocation of several commands: M-w C-s M-y
>with a bad side-effect of leaving the region in the kill-ring.
>
>However, adding a new option is not a satisfactory solution
>because often isearch is used to extend the boundaries of the
>active region, e.g. by setting the region's beginning with C-SPC,
>then searching the region's end and exiting isearch there.
>
>Fortunately, like Basil mentioned the command isearch-forward-symbol-at-point
>bound to 'M-s .' you could create a similar command bound to e.g. 'M-s r'
>that would start isearch with the text from the active region.
>