Syntax highlighting for fstab

[awebeer256]

Description of the problem or steps to reproduce

Micro appears to have no syntax highlighting for fstab files. Meanwhile, Nano at least highlights comments in them.

Specifications

Commit hash: 225927b
OS: Fedora 38
Terminal: Konsole

[JoeKar]

A possible solution could be to represent it with the ini filetype by adding it to runtime/syntax/ini.yaml.
But at the end this would mean adding dozens of files without any extensions to the ini filetype.

Maybe nano already found a good compromise by using a default syntax definition in case no other syntax highlighting fits.
Vim on the other hand respects the fstab with a dedicated definition, but this maybe goes a bit too far.

Currently I suggest to do it more or less the same as nano does, but the micro way.

[JoeKar]

Currently I suggest to do it more or less the same as nano does, but the micro way.

I'm currently working on a basic default/fallback highlighting. Maybe it will fit the needs.

[zyedidia]

Do fstab files not have an extension?

[JoeKar]

Nope, they don't.
A longer discussion in #2933 is ongoing what's needed or not in the default.yaml.

I would appreciate your opinion too. :)

[JoeKar]

Currently I'm unsure if closing this ticket with #2933 was a good decision, since the initial issue isn't really fixed. We now only have a default fallback doing some minimal highlighting for plain text.
Would this fit your needs...

{
    "/etc/*": {
        "filetype": "ini"
    },
    [...]
}

...in ~/.config/micro/settings.json?

[Klopadius]

I’m not a programmer, but I decided to share what worked for me — maybe it will help someone.

This is how I set up syntax highlighting for the fstab file. The configuration is in my ~/.config/micro/syntax/fstab.yaml:

filetype: fstab

detect:
    filename: "fstab*"

# Important: rules are applied in order — more specific matches must come after broader ones to take effect.
rules:
# Standard comment highlighting taken from ini.yaml
 - comment:
        start: "#"
        end: "$"
        rules:
            - todo: "(TODO|XXX|FIXME):?"
# Fsck pass (6th field in fstab) — value: 0, 1 or 2. Highlighting the last column.
 - blue: '^\S+\s+\S+\s+\S+\s+\S+\s+[01]\s+([012])\s*$'

# Dump flag (5th field) — allowed values: 0 or 1. Highlights the fifth column.
 - blue: '^\S+\s+\S+\s+\S+\s+\S+\s+([01])\s'

# <options> (4th field) — mount options like rw,noatime,etc. Highlights the 4th field.
 - cyan: ^[^\s]+\s+[^\s]+\s+[^\s]+\s+([^\s]+)

# <type> — (3rd field) filesystem type (e.g. ext4, vfat). Highlights the 3rd field.
 - green: '^[^\s]+\s+[^\s]+\s+([^\s]+)'

# <mount point> (2nd field) — path to where device is mounted. Highlights the 2nd field.
 - yellow: '^\S+\s+(\S+)'

# <file system>  (1st field)— device or label. Highlights the 1st field.
 - default: '^[^\s]+'

# Commas inside options field — for easier visual splitting.
 - white: ','

# Highlights values after "=" (like "uid=1000") up to comma or space.
 - brightyellow: '=([^\s,]+)'

I wasn't able to highlight each column separately, so the rules are applied sequentially. I’ve added a separate rule to highlight commas for readability. Also, characters after = (in things like subvol=/@ or UUID=) are colored for better visibility.

This may not be the most efficient solution, but it works well for me.