source-highlight's language definition file for YAML

lang.map.diff

---/usr/share/source-highlight/lang.map.old
+++/usr/share/source-highlight/lang.map
@@ -169,3 +169,5 @@
 groovy = groovy.lang
 json = json.lang
 feature = feature.lang
+yaml = yaml.lang
+yml = yaml.lang

yaml.lang

# source-highlight's language definition file for YAML

include "script_comment.lang"
include "number.lang"

keyword = "true|false|null"

section start '^---'
(symbol,name,symbol) = `(^[[:blank:]-]*)([[:alnum:]_]+)(:)`
symbol = '^[[:blank:]]*-'

# TODO:
#   - hredoc
#   - alias indicators

string delim "\"" "\"" escape "\\"
string delim "'" "'"  escape "\\"

# vim: ft=conf

For anyone stumbling upon this by googling; instructions to add this to source-highlight:

1. Put the yaml.lang file into the dir /usr/local/Cellar/source-highlight/3.1.8_9/share/source-highlight/ or similar

2. Append those two last lines yaml = yaml.lang and yml = yaml.lang to the lang.map.diff file (which is in the same directory)

3. That's it ✔️