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janet/libs/pp.gst
2017-04-27 09:44:52 -04:00

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# Pretty print
# Declare pretty print
(: pp nil)
# Pretty print an array or tuple
(: print-seq (fn [start end a seen]
(: seen (if seen seen {}))
(if (get seen s) (get seen s)
(do
(: parts [])
(: len (length a))
(: i 0)
(while (< i len)
(push! parts (pp (get a i) seen))
(push! parts " ")
(: i (+ 1 i)))
(if (> len 0) (pop! parts))
(push! parts end)
(: ret (apply string start parts))
(set! seen s ret)
ret))))
# Pretty print an object or struct
(: print-struct (fn [start end s seen]
(: seen (if seen seen {}))
(if (get seen s) (get seen s)
(do
(: parts [])
(: key (next s))
(while (not (= key nil))
(push! parts (pp key seen))
(push! parts " ")
(push! parts (pp (get s key) seen))
(push! parts " ")
(: key (next s key)))
(if (> (length parts) 0) (pop! parts))
(push! parts end)
(: ret (apply string start parts))
(set! seen s ret)
ret))))
# Type handlers
(: handlers {
"array" (fn [a seen] (print-seq "[" "]" a seen))
"tuple" (fn [a seen] (print-seq "(" ")" a seen))
"table" (fn [s seen] (print-struct "{" "}" s seen))
"struct" (fn [s seen] (print-struct "#{" "}" s seen))
})
# Define pretty print
(: pp (fn [x seen]
(: h (get handlers (type x)))
((if h h tostring) x seen)))
(print (pp [1 {4 5 6 7} 2 3]))
# Module export pattern - last expression in file is value of module
pp