Nano syntax highlighting for YAML files

yaml.nanorc

## Nano syntax highlighting for YAML files
##
## Author:      Leo Arnold
## License:     Public Domain
## URL:         https://gist.github.com/leoarnold/96272e33753aff09163cf18ad641f028

syntax "yaml" "\.(yml|yaml)$"

## Keys
icolor green "^[[:space:]]*(- )?[.0-9A-Z_/-]+:( |$)"
## Structurals
color red "(^---|^[[:space:]]*- |: |:$)"
## Strings, double-quoted
color red ""([^"]|(\\"))*""
color magenta "\$(\w+|\{\w+\})"
## Strings, single-quoted
color red "'([^']|(\\'))*'"

## Comments
color yellow "(^|[[:space:]]+)#.*$"
## Some common markers
color black,red "(TODO|FIXME|\?\?\?)"
## Trailing spaces
color ,red "[[:space:]]+$"

had to put the hyphen on the end of the block to prevent an invalid end of range error