CLOP - Common Lisp tOml Parser

Overview

Tom’s Obvious Minimal Language (TOML) is a human friendly configuration file format. This library implements a parser (decoder) for it.

Clop strictly follows TOML 1.0 specification and is fully compatible with it. It passes all 296 tests defined in BurntSushi/toml-test.

It is implemented by utilizing ESRAP, which is a really awesome library.

Installation

Once it gets into Quicklisp, you can load it by:

;; Load it.
(ql:quickload "clop")

;; Run some basic tests.
(asdf:test-system "clop")

If you want to run comprehensive tests, you need to first clone toml-test and set it up locally.

Use the following command to test it:

cd /path/to/clop/roswell
ros build decoder.ros

/path/to/toml-test/toml-test ./decoder

You should now see a line of:

toml-test [/path/to/clop/roswell/decoder]: using embedded tests: 296 passed,  0 failed

Usage

Functions

The main entry point of Clop is parse function.

  (defparameter +toml-text+ "
[server]
port = 5000
print-access-log = false
")
  
  (clop:parse +toml-text+)
  ; => (("server" ("port" . 5000) ("print-access-log")))

This function takes an optional keyword argument style that controls the output style:

• :alist. The default. TOML tables are transformed to alists.
• :jsown. TOML tables are transformed to jsown style (:obj "key" "value").
• :raw. TOML tables are transformed to Clop internal representations, i.e. classes table, table-array and inline-table.

Configurations

The behavior of Clop can be tuned by settings configuration variables. Wrap them in a let lexical context or change their values globally to make it work.

Variable	Default Value	Meaning
value-+inf	:+INF	The value of +inf
value–inf	:-INF	The value of -inf
value-+nan	:+NAN	The value of +nan
value–nan	:-NAN	The value of -nan
value-true	T	The value of boolean true
value-false	NIL	The value of boolean false

Extending Clop

Clop implementation has 2 concepts: value parser and block parser.

• Value parser is used for handling basic values, i.e. string, integer, float, bool, datetime, datetime-local, date-local, time-local.
• Block parser is used for handling TOML blocks, i.e. key-value-pair, table, inline-table and table-array.

Tuning Value Parser

For basic values, you may:

1. Define your own value parser function that takes 2 arguments: type and value, and return the resulting value.
2. Set clop.config:*value-parser* variable to your own function.

You may refer to roswell/decoder.ros for an example. toml-test requires values to be a JSON object like:

{
  "type": "integer",
  "value": 123
}

Code in roswell/decoder.ros tunes value parser to return such jsown object.

Tuning Block Parser

Instead of implementing your own block parser, you may pass a :raw style to clop:parse function and start from the return value. Check docstrings in src/toml-block-parser for more detail.