ludus/src/ludus/parser_new.clj

335 lines
12 KiB
Clojure

(ns ludus.parser-new)
(defn ? [val default] (if (nil? val) default val))
(defn ok? [{status :status}]
(= status :ok))
(def failing #{:err :none})
(def passing #{:ok :group :quiet})
(defn pass? [{status :status}] (contains? passing status))
(defn fail? [{status :status}] (contains? failing status))
(defn data [{d :data}] d)
(defn remaining [{r :remaining}] r)
(defn pname [parser] (? (:name parser) parser))
(defn str-part [kw] (apply str (next (str kw))))
(defn kw+str [kw mystr] (keyword (str (str-part kw) mystr)))
(defn value [token]
(if (= :none (:literal token)) (:lexeme token) (:literal token)))
(defn apply-kw-parser [kw tokens]
(let [token (first tokens)]
;(if (= kw (:type token)) (println "Matched " kw))
(if (= kw (:type token))
{:status :ok
:type kw
:data (if (some? (value token)) [(value token)] [])
:token token
:remaining (rest tokens)}
{:status :none :token token :trace [kw] :remaining (rest tokens)})))
(defn apply-fn-parser [parser tokens]
(let [rule (:rule parser) name (:name parser) result (rule tokens)]
;(if (pass? result) (println "Matched " (:name parser)))
result))
(defn apply-parser [parser tokens]
;(println "Applying parser " (? (:name parser) parser))
(let [result (cond
(keyword? parser) (apply-kw-parser parser tokens)
(:rule parser) (apply-fn-parser parser tokens)
(fn? parser) (apply-fn-parser (parser) tokens)
:else (throw (Exception. "`apply-parser` requires a parser")))]
;(println "Parser result " (? (:name parser) parser) (:status result))
result
))
(defn choice [name parsers]
{:name name
:rule (fn choice-fn [tokens]
(loop [ps parsers]
(let [result (apply-parser (first ps) tokens)
rem-ts (remaining result)
rem-ps (rest ps)]
(cond
(pass? result)
{:status :ok :type name :data [result] :token (first tokens) :remaining rem-ts}
(= :err (:status result))
(update result :trace #(conj % name))
(empty? rem-ps)
{:status :none :token (first tokens) :trace [name] :remaining rem-ts}
:else (recur rem-ps)))))})
(defn order-1 [name parsers]
{:name name
:rule (fn order-fn [tokens]
(let [origin (first tokens)
first-result (apply-parser (first parsers) tokens)]
(case (:status first-result)
(:err :none)
(assoc (update first-result :trace #(conj % name)) :status :none)
(:ok :quiet :group)
(loop [ps (rest parsers)
results (case (:status first-result)
:ok [first-result]
:quiet []
:group (:data first-result))
ts (remaining first-result)]
(let [result (apply-parser (first ps) ts)
res-rem (remaining result)]
(if (empty? (rest ps))
(case (:status result)
:ok {:status :group
:type name
:data (conj results result)
:token origin
:remaining res-rem}
:quiet {:status :group
:type name
:data results
:token origin
:remaining res-rem}
:group {:status :group
:type name
:data (vec (concat results (:data result)))
:token origin
:remaining res-rem}
(:err :none)
(assoc (update result :trace #(conj % name)) :status :err))
(case (:status result)
:ok (recur (rest ps) (conj results result) res-rem)
:group (recur (rest ps)
(vec (concat results (:data result)))
res-rem)
:quiet (recur (rest ps) results res-rem)
(:err :none)
(assoc (update result :trace #(conj % name)) :status :err))))))))})
(defn order-0 [name parsers]
{:name name
:rule (fn order-fn [tokens]
(let [origin (first tokens)]
(loop [ps parsers
results []
ts tokens]
(let [result (apply-parser (first ps) ts)
res-rem (remaining result)]
(if (empty? (rest ps))
;; Nothing more: return
(case (:status result)
:ok {:status :group
:type name
:data (conj results result)
:token origin
:remaining res-rem}
:quiet {:status :group
:type name
:data results
:token origin
:remaining res-rem}
:group {:status :group
:type name
:data (vec (concat results (:data result)))
:token origin
:remaining res-rem}
(:err :none)
(assoc (update result :trace #(conj % name)) :status :err))
;; Still parsers left in the vector: recur
(case (:status result)
:ok (recur (rest ps) (conj results result) res-rem)
:group (recur (rest ps)
(vec (concat results (:data result)))
res-rem)
:quiet (recur (rest ps) results res-rem)
(:err :none)
(assoc (update result :trace #(conj % name)) :status :err)
(throw (ex-info (str "Got bad result: " (:status result)) result))))))))})
(defn weak-order [name parsers]
{:name name
:rule (fn order-fn [tokens]
(let [origin (first tokens)]
(loop [ps parsers
results []
ts tokens]
(let [result (apply-parser (first ps) ts)
res-rem (remaining result)]
(if (empty? (rest ps))
;; Nothing more: return
(case (:status result)
:ok {:status :group
:type name
:data (conj results result)
:token origin
:remaining res-rem}
:quiet {:status :group
:type name
:data results
:token origin
:remaining res-rem}
:group {:status :group
:type name
:data (vec (concat results (:data result)))
:token origin
:remaining res-rem}
(:err :none)
(update result :trace #(conj % name)))
;; Still parsers left in the vector: recur
(case (:status result)
:ok (recur (rest ps) (conj results result) res-rem)
:group (recur (rest ps)
(vec (concat results (:data result)))
res-rem)
:quiet (recur (rest ps) results res-rem)
(:err :none)
(update result :trace #(conj % name))))))))})
(defn quiet [parser]
{:name (kw+str (? (:name parser) parser) "-quiet")
:rule (fn quiet-fn [tokens]
(let [result (apply-parser parser tokens)]
(if (pass? result)
(assoc result :status :quiet)
result)))})
(defn zero+
([parser] (zero+ (pname parser) parser))
([name parser]
{:name (kw+str name "-zero+")
:rule (fn zero+fn [tokens]
(loop [results []
ts tokens]
(let [result (apply-parser parser ts)]
(case (:status result)
:ok (recur (conj results result) (remaining result))
:group (recur (vec (concat results (:data result))) (remaining result))
:quiet (recur results (remaining result))
:err (update result :trace #(conj % name))
:none {:status :group
:type name
:data results
:token (first tokens)
:remaining ts}))))}))
(defn one+
([parser] (one+ (pname parser) parser))
([name parser]
{:name (kw+str name "-one+")
:rule (fn one+fn [tokens]
(let [first-result (apply-parser parser tokens)
rest-parser (zero+ name parser)]
(case (:status first-result)
(:ok :group)
(let [rest-result (apply-parser rest-parser (remaining first-result))]
(case (:status rest-result)
(:ok :group :quiet)
{:status :group
:type name
:data (vec (concat (:data first-result) (data rest-result)))
:token (first tokens)
:remaining (remaining rest-result)}
:none {:status :group :type name
:data first-result
:token (first tokens)
:remaining (remaining rest-result)}
:err (update rest-result :trace #(conj % name))))
:quiet
(let [rest-result (apply-parser rest-parser (remaining first-result))]
{:status :quiet
:type name
:data []
:token (first tokens)
:remaining (remaining rest-result)})
(:err :none) first-result)))}))
(defn maybe
([parser] (maybe (pname parser) parser))
([name parser]
{:name (kw+str name "-maybe")
:rule (fn maybe-fn [tokens]
(let [result (apply-parser parser tokens)]
(if (pass? result)
result
{:status :group :type name :data [] :token (first tokens) :remaining tokens}
)))}))
(defn flat
([parser] (flat (pname parser) parser))
([name parser]
{:name (kw+str name "-flat")
:rule (fn flat-fn [tokens]
(let [result (apply-parser parser tokens)]
(if (pass? result) (first (:data result)) result)))}))
(defn group
([parser] (group (pname parser) parser))
([name parser]
{:name (kw+str name "-group")
:rule (fn group-fn [tokens]
(let [result (apply-parser parser tokens)]
(if (= :group (:status result))
(assoc result :status :ok)
result)))}))
(defn err-msg [{token :token trace :trace}]
(println "Unexpected token " (:type token) " on line " (:line token))
(println "Expected token " (first trace)))
(defmacro defp [name & items]
(let [arg (last items)
fns (into [] (butlast items))]
`(defn ~name [] ((apply comp ~fns) (keyword '~name) ~arg))))
(macroexpand '(defp foo group choice [:one :two]))
(comment (defp foo quiet choice [:one :two])
(def group-choice (apply comp '(group choice)))
(group-choice :thing [:a :b])
((apply comp [group choice]) :foo [:one :two])
(fn? foo)
foo
(keyword 'foo)
(foo))