4 posts tagged with "project"

Here's how you can use Janet's built-in Parsing Expression Grammar (PEG) module to define a grammar capable of parsing valid JSON into an Abstract Syntax Tree in only 13 lines of code (one of which is just the "define" keyword and a symbol name):

(def json-parser
  ~{:null (/ (<- "null") ,|[$ :null])
    :bool (/ (<- (+ "true" "false")) ,|[$ :bool])
    :number (/ (<- (* (? "-") :d+ (? (* "." :d+)))) ,|[$ :number])
    :string (/ (* "\"" (<- (to (* (> -1 (not "\\")) "\""))) 
                  (* (> -1 (not "\\")) "\"")) ,|[$ :string])
    :array (/ (* "[" :value (any (* :s* "," :value)) "]") ,|[$& :array])
    :object (/ (* "{" :s* :string :s* ":" :value
                  (any (* :s* "," :s* :string :s* ":" :value))
                  "}") ,|[(from-pairs (partition 2 $&)) :object])
    :value (* :s* (+ :null :bool :number :string :array :object) :s*)
    :unmatched (/ (<- (some 1)) ,|[$ :unmatched])
    :main (some (+ :value "\n" :unmatched))})

[WIP]

One of the main reasons to prefer programming in Lisp is the ability to use Structural Programming while editing. I've been working on a VS Code extension to enable that editing style in Janet.

[WIP]

Every now and then you just need to compare a dozen almost-identical iterations of the solution to a basic toy programming problem to figure out what's faster or slower in your language of choice.

[WIP]

This is now the third iteration of a "Caleb's Notes" website to see the light of day. To celebrate, here's a brief summary of this lovable train wreck's messy history.