How to use regex to format a comma separated map structure

Question

Using a text editor, without writing JavaScript functions (e.g. can't use this great answer: Replacing the nth instance of a regex match in Javascript)

How do I take something like this (a proprietary code structure I have no control over)

map(key1, value1, key2, value2, key3, value3, key4, value4 ...)

And convert it to this

map(
  key1, value1,
  key2, value2,
  key3, value3,
  key4, value4 
  ...
)

One option I found was using this regex to find every 2nd comma (([^,]*,){2})

Then replace with \1\n\t

But I would like to improve it:

1. It doen't handle the first and last lines very well

 map(key1, value1,
    key2, value2,
    key3, value3,
    key4, value4 ...)

2. Only works on a flat structure

e.g. I can't think of a way to transform this

map(key1, value1, key2, map(key3, value3, key4, value4 ...), key5, value5)

To this

map(
  key1,value1,
  key2,map(
    key3,value3,
    key4,value4 
  ),
  key5,value5    
)

Using regex, or is there a way?

if you tag it with vim, one day you will throw notepad-- away. :) — Kent, Feb 08 '13 at 21:15
Use a scripting language (eg Perl, Python, Ruby, etc) to perform the change. That's what those tools are for. Especially since you can have nested `map` statements...you'll want to write a parser. — , Feb 08 '13 at 21:17
@Kent ok :) funny I didn't think to look for a windows based vim, just downloaded one, will try — Eran Medan, Feb 08 '13 at 21:35
@JackManey yep, I would default to that, but was hoping there is a way to have a shortcut in an editor to do that, I guess the answer is simply write a sublime text 2 python plugin (and I'm sure you could do the same for vim). Just wondered if there is anyway to use regex for this solely... — Eran Medan, Feb 08 '13 at 21:42

score 3 · Accepted Answer · answered Feb 09 '13 at 01:36

Eran, oh you finally tag the question with vim, nice! ^_^

vim can format it a bit, I wrote a small function:

Note that I used \r as linebreak, if it doesn't work for you, change into \n

function! ExpandMap()
    let s = line('.')
    exec 'silent s/(/(\r/g'
    let e = line('.')
    exec 'silent '.s.','.e.'s/),\=/\r&\r/g'
    let e = line('.')
    exec 'silent '.s.','.e.'s/,[^,]*\zs,\ze/,\r/g'
    let e = line('.')
    exec s.','.e.' normal =='
endfunction

You can put it in your .vimrc file, if you use that very often. Also you could just give it a try by typing :so %

You can create a map for that function call by:

`nnoremap <leader>r :call ExpandMap()<cr>`

in this way, if you want to reformat your map line, just move cursor to that line, and in Normal mode type <leader>r (default is \)

This function will change

map(k1, v1, k2,  map(k3, v3, k4, v4), k5, v5, k6, map(k7, v7,k8,v8,k9,v9),k10,v10,k11,v11)

into

map(
        k1, v1,
        k2,  map(
            k3, v3,
            k4, v4
            ),
        k5, v5,
        k6, map(
            k7, v7,
            k8,v8,
            k9,v9
            ),
        k10,v10,
        k11,v11
)

Here I show how it works:

I split the window into two, just show the function
I created a mapping after the function
I make two nested maps, also to make the line short, I just used k#, v#

enter image description here

Now, when are you gonna uninstall your notepad++? ^_^

score 1 · Answer 2 · edited May 23 '17 at 12:12

1

A very basic implementation, replacing "Down" in the direction of text.

Find:

([^(,)]+,[^(,)]+)

Replace:

\n\t\1

Note that this does not work on ... (what is that?), and it does not do anything fancy with nesting depth. Keeping track of the nesting depth would require a parser with abilities beyond those of regex. Parsing a programming language is as hard as parsing HTML.

edited May 23 '17 at 12:12

Community

1
1

answered Feb 08 '13 at 21:21

Blue Magister

13,044
5
38
56

oh, the ... means "and so on" (e.g. the number of pairs is not known). Ok, makes sense, so Regex is the tokenizer/lexer and I need a parser to make an AST out of it (or something like that?) – Eran Medan Feb 08 '13 at 21:36
I don't have a lot of experience with those terms (I just Wiki'd them) but that sounds accurate. – Blue Magister Feb 08 '13 at 22:18

How to use regex to format a comma separated map structure

2 Answers2