evalator-clojure.clj

;;; evalator-clojure.clj --- Clojure backend for CIDER context.
;;
;; Author: Sean Irby
;; Copyright © , Sean Irby
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or (at
;; your option) any later version.
;;
;; This program is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;; This file is not a part of GNU Emacs
;;
;;; Commentary:
;;
;;  This file is required, fully-qualified, in the current namespace
;;  when an evalator session is started with 'evalator-clojure'
;;  as the evaluation context.  CIDER will call these functions as
;;  needed when a result needs to be generated.
;;
;;; Code:


(ns evalator-clojure
  (:require [clojure.string :as s :refer [replace join]]))

;; value is swapped when evalator session starts
(def special-arg-str (atom nil))

(defn swap-special-arg-str [str]
  "Swaps special-arg-str atom with STR"
  (swap! special-arg-str #(identity %2) str))

(defn numbered-arg-pattern
  "Return the regex pattern used to match a numbered special arg like
   \" ⒺN \".  If QUOTE? is true then a pattern is returned that can also
   match a quoted numbered special arg like \"'ⒺN\"."
  ([]
   (numbered-arg-pattern false))
  ([quote?]
   (let [frmt (if quote? "'?%s([0-9]+)" "%s([0-9]+)")]
     (re-pattern (format frmt @special-arg-str)))))

(defn identity-arg-pattern
  "Return the regex pattern used to match identity special args.  If
   QUOTE? is true then a pattern is returned that can also match a
   quoted identity special arg like \"'Ⓔ\"."
  ([]
   (identity-arg-pattern false))
  ([quote?]
   (let [frmt (if quote? "'?%s" "%s")]
     (re-pattern (format frmt @special-arg-str)))))

(defn subst-numbered-special-args [expr-str c]
  "Substitute any special args of the form \"ⒺN\" in EXPR-STR with the
  Nth element in C."
  (s/replace expr-str (numbered-arg-pattern) #(pr-str (nth c (Integer. (last %))))))

(defn subst-identity-special-args [expr-str c]
  "Substitute any special args of the form \"Ⓔ\" in EXPR-STR with C."
  (s/replace expr-str (identity-arg-pattern) (pr-str c)))

(defn subst-special-args [expr-str c]
  "Substitute any special args in EXPR-STR.  Identity special args
   like \"Ⓔ\" are substituted with the value of C.  Numbered special
   args like \"ⒺN\" are substituted with the Nth element in C."
  (-> expr-str
    (subst-numbered-special-args c)
    (subst-identity-special-args c)))

(defn eval-expression [expr-str]
  "Evaluate the expression string, EXPR-STR."
  (eval (read-string expr-str)))

(defn make-equiv-expr [exprs]
  "See slot documentation in evalator-context.el in evalator package."
  (let [sub-numbered-args #(s/replace %2 (numbered-arg-pattern true) (format "(nth %s $1)" %1))
        sub-identity-args #(s/replace %2 (identity-arg-pattern true) %1)
        sub (fn [e1 e2] (sub-identity-args e1 (sub-numbered-args e1 e2)))]
    (reduce sub exprs)))

(defn make-candidates [input mode]
  "See slot documentation in evalator-context.el in evalator package."
  (let [data (eval (read-string input))]
    (cond (= :explicit mode)
          (list (pr-str data))

          (sequential? data)
          (map pr-str data)

          :else
          (list (pr-str data)))))

(defn transform-candidates [cands expr-str collect?]
  "See slot documentation in evalator-context.el in evalator package."
  (let [cands-v (vec cands)]
    (map pr-str
      (if collect?
        (list (eval-expression (subst-special-args expr-str (mapv read-string cands-v))))
        (map #(eval-expression (subst-special-args expr-str (read-string %))) cands-v)))))

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;;; evalator-clojure.clj ends here