scratch.clj

(require '[instaparse.core :as insta])

(def grammar
  "A PEG grammar to validate and parse conventional commit messages."
  (str
    "<S>            =       (HEADER <EMPTY-LINE> FOOTER GIT-REPORT? <NEWLINE>*)
                            / ( HEADER <EMPTY-LINE> BODY (<EMPTY-LINE> FOOTER)? GIT-REPORT? <NEWLINE>*)

                            / (HEADER <EMPTY-LINE> BODY GIT-REPORT? <NEWLINE>*)
                            / (HEADER GIT-REPORT? <NEWLINE>*);"
    "<HEADER>       =       TYPE (<'('>SCOPE<')'>)? <':'> <SPACE> SUBJECT;"
    "TYPE           =       'feat' | 'fix' | 'refactor' | 'perf' | 'style' | 'test' | 'docs' | 'build' | 'ops' | 'chore';"
    "SCOPE          =       #'[a-zA-Z0-9]+';"
    "SUBJECT        =       TEXT ISSUE-REF? TEXT? !'.';"
    "BODY           =       (!PRE-FOOTER PARAGRAPH) / (!PRE-FOOTER PARAGRAPH (<EMPTY-LINE> PARAGRAPH)*);"
    "PARAGRAPH      =       (ISSUE-REF / TEXT / (NEWLINE !NEWLINE))+;"
    "PRE-FOOTER     =       NEWLINE+ FOOTER;"
    "FOOTER         =       FOOTER-ELEMENT (<NEWLINE> FOOTER-ELEMENT)*;"
    "FOOTER-ELEMENT =       FOOTER-TOKEN <':'> <WHITESPACE> FOOTER-VALUE;"
    "FOOTER-TOKEN   =       ('BREAKING CHANGE' (<'('>SCOPE<')'>)?) / #'[a-zA-Z\\-^\\#]+';"
    "FOOTER-VALUE   =       (ISSUE-REF / TEXT)+;"
    "GIT-REPORT     =       (<EMPTY-LINE> / <NEWLINE>) COMMENT*;"
    "COMMENT        =       <'#'> #'[^\\n]*' <NEWLINE?> ;"
    "ISSUE-REF      =       <'#'> ISSUE-ID;"
    "ISSUE-ID       =       #'([A-Z]+\\-)?[0-9]+';"
    "TEXT           =       #'[^\\n\\#]+';"
    "SPACE          =       ' ';"
    "WHITESPACE     =       #'\\s';"
    "NEWLINE        =       <'\n'>;"
    "EMPTY-LINE     =       <'\n\n'>;"))

(def parser (insta/parser grammar))

(insta/parse parser "feat: adding a new awesome feature")