ngron

Nim reimplementation of the great gron tool.

Converts json text into Javascript statements, and makes it easy to grep!

Example

Lets take a very simple json file

{
  "integer": 1,
  "float": 2.1,
  "string": "string",
  "array": [
    0,
    "1",
    2.0
  ],
  "nest": {
    "ted": "ಠ_ಠ",
    "boolean": true,
    "null": null
  }
}

We can save it as test.json. Now lets try to play with it using ngron

Lets convert it to gron, which outputs valid json assignment statements that would generate the json input

> ./ngron test.json
json = {};
json.integer = 1;
json.float = 2.1;
json.string = "string";
json.array = [];
json.array[0] = 0;
json.array[1] = "1";
json.array[2] = 2.0;
json.nest = {};
json.nest.ted = "ಠ_ಠ";
json.nest.boolean = true;
json.nest.null = null;

Or jgron, which outputs a stream of paths and values tuples

> ./ngron -o jgron test.json
[[],{}]
[["integer"],1]
[["float"],2.1]
[["string"],"string"]
[["array"],[]]
[["array",0],0]
[["array",1],"1"]
[["array",2],2.0]
[["nest"],{}]
[["nest","ted"],"ಠ_ಠ"]
[["nest","boolean"],true]
[["nest","null"],null]

Lets save the gron output to a file out.gron

> ./ngron test.json > out.gron

And finally lets convert our out.gron file to get the original json input

> ./ngron -o json out.gron 
{
  "integer": 1,
  "float": 2.1,
  "string": "string",
  "array": [
    0,
    "1",
    2.0
  ],
  "nest": {
    "ted": "ಠ_ಠ",
    "boolean": true,
    "null": null
  }
}

You can also use your clipboard as an input source with the -c flag

CLI Help

Transform JSON (from a file, URL, clipboard or stdin) into discrete assignments to make it greppable

Usage:
   [options] [input]

Arguments:
  [input]          Path to file or URL path. Ignored if piping from  stdin (default: stdin)

Options:
  -h, --help
  --version                  Print version information
  -s, --sort                 Sort keys (slower)
  -v, --values               Print just the values of provided assignments
  -c, --clipboard            Use clipboard as input
  -r, --raw                  Print without color (ignores input argument)
  -i, --input-type=INPUT_TYPE
                             Input type (Inferred from file extension) Possible values: [json, gron, jgron] (default: json)
  -o, --output-type=OUTPUT_TYPE
                             Output type Possible values: [json, gron, jgron] (default: gron)

Requirements

To build and develop you will need

• git
• nimble
• nim >= 2.0.4

Features

• Input Types
  • File
  • URL (http/https)
  • Clipboard
  • stdin
• Input formats
  • JSON
  • JSON stream
  • gron
  • jgron
• Output formats
  • JSON
  • gron
  • jgron
• Output formatting
  • Sorted keys
  • Colorized
  • Values only

Things to do

• Broader testing
  • Large files, weird characters.
  • Windows, Mac OS
• Full compliance with JSON spec
  • Identifiers are not really compliant with the spec
• Benchmarks and test
  • Memory consumption and performance vs original implementation
• Optimizations
  • Compact json object data structure
  • Stream input instead of reading all string in memory
  • Better handling of allocations in tokenizer/parser
  • Multithreading
• Prebuilt binaries

Tests

The test files of the original gron are part of this repository, they are located in tests/resources/gron

Other tests files are added to the folder tests/resources

The original testing and development has been carried on Ubuntu 20.4

Resources

• gron repository
• Nim std library docs
• Crafting interpreters book. The parsers are heavily inspired on the book!
• Scripter's notes on tty on Nim, has some great info on Nim tricks all around