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janet/libs/pp.gst
2017-05-07 18:20:11 -04:00

66 lines
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Plaintext

(do
(: pp nil)
"Pretty print an array or tuple"
(: print-seq (fn [start end a seen]
(: seen (if seen seen {}))
(if (get seen a) (get seen a)
(do
(set! seen a "<cycle>")
(: 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 a 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
(set! seen s "<cycle>")
(: 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]
(: handler (get handlers (type x)))
(: handler (if handler handler tostring))
(handler x seen)))
"Export pretty print"
(export! "pp" pp)
(: arr [1 2 3 4])
(push! arr arr)
(print (pp arr))
)