An extremely simple parser combinator library
The library provides several matchers for common use cases, which you can combine as you wish. When you call one of the matcher functions, it will return a function which expects a context object.
(all-m (str-m "hello") (regex-m #"\s+") (str-m "world")) (context "hello world"))
; -> {:success true, :value ["hello" " " "world"], :ctx Context{:text "hello world", :pos 14}}
(all-m (str-m "hello") (regex-m #"\s+") (str-m "world")) (context "hello"))
; -> {:success false, :value "expected \\s+", :ctx nil}(defmacro defnode [node-name matcher]
`(def ~node-name
(parse/map-m ~matcher
(fn [value#] [~(keyword node-name) value#]))))
(def space (parse/regex-m #" +"))
(def crlf (parse/str-m "\r\n"))
(def colon (parse/str-m ":"))
(def letter (parse/regex-m #"[a-zA-Z]+"))
(def three-numbers (parse/regex-m #"[0-9][0-9][0-9]"))
(def hostname (parse/regex-m #"(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])"))
(defnode trailing (parse/regex-m #"[^\x00\r\n]*"))
(defnode middle (parse/regex-m #"[^:][^\x00\r\n ]*"))
(defnode host hostname)
(defnode servername hostname)
(defnode nick (parse/regex-m #"[a-zA-Z][a-zA-Z0-9\-\[\]\\`\^{}]*"))
(defnode user (parse/regex-m #"[^ \x00\r\n@]+"))
; <params> ::= <SPACE> [ ':' <trailing> | <middle> <params> ]
(defnode params
(parse/optional-m
(parse/all-m space
(parse/optional-m (parse/any-m (parse/all-m colon trailing)
(parse/all-m middle #'example.irc/params))))))
; <command> ::= <letter> { <letter> } | <number> <number> <number>
(defnode command (parse/any-m letter (parse/all-m three-numbers)))
; <prefix> ::= <servername> | <nick> [ '!' <user> ] [ '@' <host> ]
(defnode prefix
(parse/all-m (parse/any-m servername nick)
(parse/all-m
(parse/optional-m (parse/all-m (parse/str-m "!") user))
(parse/optional-m (parse/all-m (parse/str-m "@") host)))))
; <message> ::= [':' <prefix> <SPACE> ] <command> <params> <crlf>
(defnode message
(parse/all-m
(parse/optional-m
(parse/all-m (parse/str-m ":")
prefix
space))
command
params
crlf))
(defn conj-mk-list [old value]
(cond
(nil? old) value
(coll? old) (conj old value)
:else [old value]))
(defn select-irc-keys
"make a map with the set of keywords as keys and the value in the coll directly
after the keyword as value"
[coll keywords]
(reduce (fn [m [k v]]
(if (keywords k)
(update m k #(conj-mk-list % v))
m))
{}
(partition 2 1 coll)))
(defn parse-message [line]
(-> (message (->Context line 0))
:value
flatten
(select-irc-keys #{:command :trailing :user :middle})
(clojure.set/rename-keys {:trailing :content :middle :channel})))