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* bug#46301: 28.0.50; cc-mode: add support for c++ lambda expression
@ 2021-02-04 15:47 Utkarsh Singh
  2021-02-23 19:19 ` Alan Mackenzie
  0 siblings, 1 reply; 6+ messages in thread
From: Utkarsh Singh @ 2021-02-04 15:47 UTC (permalink / raw)
  To: 46301


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Hi,

This bugs only occurs when we assign lambda expression as default
arguments in C++.  I know there are better ways of using lambda but I
was just playing with both C++ and Emacs on a hobby project.

Consider this C++ code:

template <typename T>
void bubble_sort(std :: vector<T> &v, bool cmp(T, T)=[](T a, T b){return a < b;})
{
    bool swapped = true;
    for(size_t i = 0; i < v.size() && swapped; i++) {
	swapped = false;
	for(size_t j = 0; j < v.size()-i; j++){
	    if(cmp(v[j+1], v[j])) {
		std::swap(v[j], v[j+1]);
		swapped=true;
	    }
	}
    }
}

Here cmp takes a lambda as default argument and if in c++-mode if we try
using C-M-e(c-end-of-defun) it will get trapped into lambda.

To solve this is added c-forward-to-nth

((memq where '(at-function-end outwith-function at-header in-header))
    (when (c-syntactic-re-search-forward "{" nil 'eob)
      (backward-char)
      (forward-sexp)

      ;; continue to move sexp if we are looking ) and ,
      (while (looking-at ")\\|,")
	(c-syntactic-re-search-forward "{" nil 'eob)
	(backward-char)
	(forward-sexp))

      (setq n (1- n))))

By this I am trying to move forward lambda's which are separated by ','
or ended with ')'.  I will also attaching the necessary diff to support
the issue.
--
Utkarsh Singh

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1970a1971,1976
> 
>       (while (looking-at ")\\|,")
> 	(c-syntactic-re-search-forward "{" nil 'eob)
> 	(backward-char)
> 	(forward-sexp))
> 

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^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-03-01 19:34 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-04 15:47 bug#46301: 28.0.50; cc-mode: add support for c++ lambda expression Utkarsh Singh
2021-02-23 19:19 ` Alan Mackenzie
2021-02-24  4:07   ` Utkarsh Singh
2021-02-25 20:51     ` Alan Mackenzie
2021-02-27 15:47       ` Utkarsh Singh
2021-03-01 19:34         ` Alan Mackenzie

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