janet/lib/pp.dst

(def a (fn [] 2))
#
# Copyright (c) 2017 Calvin Rose
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.
#

# Define a simple pretty printer

(def pp (do

(defn pp-seq [pp seen buf a start end]
 (if (get seen a)
  (buffer-push-string buf "<cycle>")
  (do
   (put seen a true)
   (def len (length a))
   (buffer-push-string buf start)
   (for [i 0 len]
    (when (not= i 0) (buffer-push-string buf " "))
    (pp seen buf (get a i)))
   (buffer-push-string buf end)
  ))
 buf)
  
(defn pp-dict [pp seen buf a start end]
 (if (get seen a)
  (buffer-push-string buf "<cycle>")
  (do
   (put seen a true)
   (var k (next a nil))
   (buffer-push-string buf start)
   (while k
    (def v (get a k))
    (pp seen buf k)
    (buffer-push-string buf " ")
    (pp seen buf v)
    (varset! k (next a k))
    (when k (buffer-push-string buf " "))
   )
   (buffer-push-string buf end)
  ))
 buf)

(def _printers {
 :array  (fn [pp seen buf x] (pp-seq pp seen buf x "[" "]"))
 :tuple  (fn [pp seen buf x] (pp-seq pp seen buf x "(" ")"))
 :table  (fn [pp seen buf x] (pp-dict pp seen buf x "@{" "}"))
 :struct (fn [pp seen buf x] (pp-dict pp seen buf x "{" "}"))
})

(defn _default_printer [pp seen buf x] 
 (buffer-push-string buf (string x)) 
 buf)

(defn pp1 [seen buf x]
  (def pmaybe (get _printers (type x)))
  (def p (if pmaybe pmaybe _default_printer))
  (p pp1 seen buf x))

(fn [x] (print (pp1 @{} @"" x)))))