VS Code snippet to capitalize each word in filename

Question

I'm trying to write a code snippet to capitalize each word in the filename base where the words are separated by dashes. While I know the words in the filename base will be separated by dashes, I don't know how may words to expect in the filename base. There could be zero or more dashes in my filename base. So, I could have:

name.extension
some-file-name.extension
yet-another-file-name.extension
and-yet-even-another-file-name.extension

etc., and I'd like these to become

Some File Name
Yet Another File Name
And Yet Even Another File Name

etc., respectively, in my code.

I've tried in an attempt just to get the first word to capitalize, but this only drops the first letter of my filename base, and leaves the rest unchanged:

${TM_FILENAME_BASE/[\\w+]/${1:/capitalize}/}

What am I missing? How do I iterate with the snippets syntax?

Answer 1

To answer your questions in your answer about conditional transforms using this snippet body:

${TM_FILENAME_BASE/(\\w+)|(\\W+)/${1:/capitalize}${2:+ }/g}

The conditional replacements are explained here: snippets grammar.

                | '${' int ':+' if '}'
                | '${' int ':?' if ':' else '}'
                | '${' int ':-' else '}' | '${' int ':' else '}'

${2:+ } is an if transform. If there is a group 2 insert a space.

${2: } is one of the two else transforms from the last line above. So ${2: } means if there is a capture group 2 do nothing but else (meaning there is no group 2) then insert a space.

The g flag makes the transform run as many times as it finds a match. So whenever the (\\W+) part of your regex matches that means there was no group 1 (since you are using an alternate | in the regex and there was a group 2. So how does your snippet work if you use the ${2: } form? You have to work through each match.

Using some-file-name:

The first match will be capture group 1 some and no capture group 2. Now the entire transform gets applied to that match. Group 1 gets capitalized and since there is no group 2 on the first match, the else ${2: } is triggered and a space is inserted.

Then the next match will be no group 1 and a group 2 of -. The replacement part of the transform will not capitalize anything (since there is no group 1). The ${2: } will insert nothing (since there is a group 2). But it seems to be inserting group 2 - which is non-obvious to me and actually seems like a bug. It is operating as if it read: if group 2, insert group 2, else (no group 2) insert a space. That is a little surprising to me. In any case, it explains why the - which is matched (in the 2nd/4th/6th/etc. match) inserts the group 2 -.

Answer 2

If you use the following body it works

• a literal . and extension => ignore
• catch a possible - followed by text until a . or -
• substitute the - by a space and capitalize the word

"body": "${TM_FILENAME_BASE/(\\.\\w+$)|(-?)([^-.]+)/${2:+ }${3:/capitalize}/g}"

It works for ${TM_FILENAME} and ${TM_FILENAME_BASE}

---

Edit

The examples all contain extensions but it turns out that ${TM_FILENAME_BASE} strips the extension.

I have tested the snippet with ${TM_SELECTED_TEXT} and the examples.

An update of the snippet body:

"body": "${TM_FILENAME_BASE/(-?)([^-]+)/${1:+ }${2:/capitalize}/g}"

Answer 3

I managed to get this to work with the following, but I don't understand why it works. Please edit this response if you can help out.

This will return the desired string:

${TM_FILENAME_BASE/(\\w+)|(\\W+)/${1:/capitalize}${2:+ }/g}

Explanation:

• TM_FILENAME_BASE is a Code snippets variable. It doesn't include the extension, so we don't need to worry about writing a regex expression to get rid of that; we get to start with (e.g.) some-file-name.
• (\\w+)|(\\W+) defines two regex search groups:
  • (\\w+) returns any group of alphanumeric text
  • (\\W+) returns any group of non-alphanumeric text
• ${1:/capitalize}${2:+ }/g capitalizes the first group, and if it finds a second group will remove and replace the dashes with a space. The final /g switch makes the entire expression greedy.

Here's the bit I don't get: I don't understand why I need the + in ${2:+ }. If I use ${2: }, though (no +), the return value comes out as Some -File -Name (note also final trailing space in addition to the other unexpected aspects of the return value).