feat: add config option for a tree indent width

[mivort]

This PR adds 'indent_width' option to configure visible indent for tree nesting levels (default is 2). Both enabled and disabled indent markers are supported.

A little context: 9a02ded seemingly removed the ability to have a compact 1-symbol width indentations (and also without indent markers it was only possible to have a fixed 2-space indents, no more, no less). This PR adds ability to have a both smaller and larger (3+) indentations.

[alex-courtis]

This is looking good; everything appears functional.

This is a complex piece of functionality that has experienced difficulties in the past.

I will:

• exhaustively test manually
• soak it for a week or so in a variety of configurations

[alex-courtis]

When we have two character icons the bottom is indented too far. That is a result of the assumption that glyphs are a single character, which is reasonable.

This is an edge case however we should deal with it.

Please:

• in padding setup: trim icons to the first character; set to a single space if they are length 0.
• add to the documentation: Icons shown before the file/directory. Length 1.

[alex-courtis]

indent_width = 0 is "working" when indent markers enabled and disabled. What should we do when 0 and markers?

This is a questionable use case and adds complication e.g. local indent = string.rep(" ", M.config.indent_width - 1)

Let's remove it:

• set to 1 when less than 1 in padding setup
• add documentation Number of spaces for an each tree nesting level. Minimum 1.

[alex-courtis]

Test Cases

indent_markers.enable = false

• 1
• 2
• 3
• 3 folder
• 3 folder folder_arrow
• 3 folder_arrow

indent_markers.enable = true

• 1
• 1 folder
• 1 folder folder_arrow
• 1 folder_arrow
• 1 inline_arrows
• 1 inline_arrows folder
• 1 inline_arrows folder folder_arrow
• 1 inline_arrows folder_arrow
• 3
• 3 folder
• 3 folder folder_arrow
• 3 folder_arrow
• 3 inline_arrows
• 3 inline_arrows folder
• 3 inline_arrows folder folder_arrow
• 3 inline_arrows folder_arrow

[alex-courtis]

• minimum width 1
• single character icons

[alex-courtis]

This has worked well for a week in a variety of situations.

Discovered existing bug #1524 which can be fixed afterwards.

Will merge following changes #1505 (review)

[alex-courtis]

• minimum width 1
• single character icons

Nudge @mivort

#1505 (comment)

[mivort]

@alex-courtis Sorry for the late update. I've updated doc and added checks for minimal indent width and marker symbol width.
Please take note I've used this solution to implement retrieval of the first UTF-8 character (since :sub(1, 1) doesn't properly handle multi-byte characters).

[alex-courtis]

Retest da6a766

indent_markers.enable = false

• 0
• 1
• 2
• 3
• 3 folder
• 3 folder folder_arrow
• 3 folder_arrow

indent_markers.enable = true

• 0
• 1
• 1 folder
• 1 folder folder_arrow
• 1 folder_arrow
• 1 inline_arrows
• 1 inline_arrows folder
• 1 inline_arrows folder folder_arrow
• 1 inline_arrows folder_arrow
• 3
• 3 folder
• 3 folder folder_arrow
• 3 folder_arrow
• 3 inline_arrows
• 3 inline_arrows folder
• 3 inline_arrows folder folder_arrow
• 3 inline_arrows folder_arrow

[alex-courtis]

@alex-courtis Sorry for the late update. I've updated doc and added checks for minimal indent width and marker symbol width. Please take note I've used this solution to implement retrieval of the first UTF-8 character (since :sub(1, 1) doesn't properly handle multi-byte characters).

Nice work.

Please add a comment, something like:
-- return the first character from the UTF-8 encoded string; we may use utf8.codes from Lua 5.3 when available

Testing now...

[alex-courtis]

The recent update to nerd hack font has change the glyphs and they don't line up nicely any more:

Fortunately that's unrelated to this change and everything here is working nicely.

[alex-courtis]

Many thanks @mivort

We can now customise the tree to look exactly as we want.

[alex-courtis]

The recent update to nerd hack font has change the glyphs and they don't line up nicely any more:

Resolution: #1561