#!/usr/bin/env janet

(def to-ast
   ~{
    :ws (set " \t\r\f\n\0\v")
    :readermac (set "';~,|")
    :symchars (+ (range "09" "AZ" "az" "\x80\xFF") (set "!$%&*+-./:<?=>@^_"))
    :token (some :symchars)
    :hex (range "09" "af" "AF")
    :escape (* "\\" (+ (set `"'0?\abefnrtvz`)
                       (* "x" :hex :hex)
                       (* "u" [4 :hex])
                       (* "U" [6 :hex])
                       (error (constant "bad escape"))))
    :comment (* "#" (any (if-not (+ "\n" -1) 1)))
    :symbol :token
    :keyword (* ":" (any :symchars))
    :constant (* (+ "true" "false" "nil") (not :symchars))
    :bytes (* "\"" (any (+ :escape (if-not "\"" 1))) "\"")
    :string :bytes
    :buffer (* "@" :bytes)
    :long-bytes {:delim (some "`")
                 :open (capture :delim :n)
                 :close (cmt (* (not (> -1 "`")) (-> :n) '(backmatch :n)) ,=)
                 :main (drop (* :open (any (if-not :close 1)) :close))}
    :long-string :long-bytes
    :long-buffer (* "@" :long-bytes)
    :number (cmt (<- :token) ,scan-number)
    :raw-value (+ :comment :constant :number :keyword
                  :string :buffer :long-string :long-buffer
                  :parray :barray :ptuple :btuple :struct :dict :symbol)
    :value (* (any (+ :ws :readermac)) :raw-value (any :ws))
    :root (any :value)
    :root2 (any (* :value :value))
    :ptuple (* "(" :root (+ ")" (error "")))
    :btuple (* "[" :root (+ "]" (error "")))
    :struct (* "{" :root2 (+ "}" (error "")))
    :parray (* "@" :ptuple)
    :barray (* "@" :btuple)
    :dict (* "@" :struct)
    :main :root})