JSON Parser

trying to build a smol json-parser in go, part of this challenge: https://codingchallenges.fyi/challenges/challenge-json-parser

current state: tested on all of testData [step1 to step4]

---

approach & pseudocode:

• json is made up of objects, arrays, strings, numbers, booleans, and null.

• ex of a valid json string: {"name": "Rohan", "interested": ["hiking", "coffee"]}

• steps to parse:

  • Tokenize: scan the input string into meaningful tokens:

    • {
    • "name"
    • :
    • "Rohan"
    • ,
    • "interested"
    • :
    • [
    • "hiking"
    • ,
    • "coffee"
    • ]
    • }

  • Parsing: Parse these tokens using recursive descent

    1. found { -> parse the object til we find the closing tag.
    • if not found, it's not a valid json.
    2. found a key "name" -> next token should be a colon
    • if not, it's not a valid json.
    3. found a colon : -> next token should be any one of the following values:

    • a string

    • a number

    • a boolean

    • null

    • an array opening bracket

    • an object's opening bracket

    • if it's not any of those, then it's an invalid json.

    4. found a string "Rohan" -> next token should either be a , or }
    • if it is a comma, go to next token
    • if it is a closing paran, json is completed and it's a vaild json.

    5. repeating step 2 & 3

    6. found [ -> parse the array till it's closing tag

    • if not valid array or no closing ] found, then its an invalid json.
    7. found ]
    8. found } -> json string completed -> it's a valid json

---

build:

go build

run:

./json-parser-go test.json

cat test.json | ./json-parser-go