Gentle reminder :) On Fri, May 3, 2019 at 6:24 PM C K Kashyap <ckkash...@gmail.com> wrote:
> Hi all, > I've made an attempt at JSON parsing. I did this since json.l at > https://github.com/aw/picolisp-json does not handle floating numbers and > that is something I need. I also took it as an opportunity to implement > something bigger than a function and get some feedback about it - I used > xml.l from picolisp source as a reference. What would be a good way to use > this implementation to parse an json string - as opposed to input from a > file. > The code is located here - > https://gist.github.com/ckkashyap/90602086fd4edafa75897a131f8cb88a - I > also have it inline for the folks reluctant to click on the link :) > > (de parse-json () > (skip) > (case (peek) > ("\"" (read-string)) > ("{" (read-object)) > ("[" (read-array)) > ("t" (read-bare-word "true")) > ("f" (read-bare-word "false")) > ("n" (read-bare-word "null")) > (T (read-number)))) > > (de expect (C) > (skip) > (let P (peek) > (unless (= P C) (quit (pack "Expected <" C "> Got <" P ">"))))) > > (de read-string () > (expect "\"") > (char) > (let R > (make > (while (not (= (peek) "\"")) > (case (peek) > ("\\" (char) (link (char))) > (T (link (char)))))) > (char) > (pack R))) > > (de read-object () (read-collection read-key-value "{" "}")) > > (de read-array () (read-collection parse-json "[" "]")) > > (de read-bare-word (W) > (skip) > (let R > (pack > (make (do (length W) (link (char))))) > (prog (unless (= W R) (quit (pack "Expected " W ", got " R))) R))) > > (de read-number () > (skip) > (let ( > Neg (if (= "-" (peek)) (char)) > _ (unless (isNum (peek)) (quit (pack "Not an number " (peek)))) > Flt NIL > R (make (while (isNum (peek)) (if (= "." (peek)) (setq Flt T)) (link > (char))))) > (round (pack (if Neg "-") R (unless Flt ".0"))))) > > (de read-key-value () > (let ( > k (read-string) > _ (skip) > _ (unless (= (char) ":") (exit ":" (peek))) > v (parse-json)) > (list k v))) > > (de read-collection (F S E) > (expect S) > (char) > (let R > (make > (while (not (= (peek) E)) > (link (F)) > (skip) > (if (= (peek) ",") (prog (char) (skip) (if (= E (peek)) (quit > "Incorrect collection termination")))))) > (char) > R)) > > (de isNum (n) (or (= "." n) (num? (format n)))) > > > Regards, > Kashyap >
