Comparison of Vim and Emacs for a substitution operation using regular expressions

Preface

This article is a summary of two previous posts that you can read at these pages:

The topic of “regular expressions” in Vim and Emacs is well suited for a functional comparison across the four different scenarios covered in the above articles to which I refer for a description of the syntax.

Comparation Table

Target Vim Emacs
Delete “pure” blank lines :g/^$/d M-x flush-lines <RET> ^$ <RET>
Delete blank lines with whitespace :g/^\s*$/d M-x flush-lines <RET> ^\s-*$ <RET>
Reduce “pure” blank lines :g/^$\n^$/d M-x query-replace-regexp <RET> ^C-qC-j\{2,\} <RET> C-qC-j <RET>
Reduce blank lines with whitespace g/^\s*$\n^\s*$/d ^\(^C-q<SPC>*C-qC-j\)\{2,\} <RET> C-qC-j <RET>

Emacs: what you type is not what you see

As explained in the article on Emacs, what you type is not what you see.

Below is a brief summary table for the operation of “reducing” blank lines, the third and fourth formulas in the above table, by distinguishing the keys pressed from the characters displayed.

Type Visualize
^C-qC-j\{2,\} <RET> C-qC-j <RET> ^^J\{2,\} → ^J
^\(^C-q<SPC>*C-qC-j\)\{2,\}<RET> C-qC-j <RET> ^\(^ *^J\)\{2,\} → ^J

Short summary

The subject of regular expressions in Vim and Emacs shows several differences between the two editors.

I am unable to determine which implementation is the best one.

It is necessary, in any case, to consider that Emacs has a very good emulator of Vim, called Evil, that allows one to use the same regular expression language as the source editor.

Thank you for your attention.

Originally published at https://francopasut.netlify.app

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