'Rcpp' Bindings to Parser for Tom's Obvious Markup Language

The configuration format defined by 'TOML' (which expands to "Tom's Obvious Markup Language") specifies an excellent format (described at < https://github.com/toml-lang/toml>) suitable for both human editing as well as the common uses of a machine-readable format. This package uses 'Rcpp' to connect the 'cpptoml' parser written by Chase Geigle (in modern C++11) to R.

Status](https://travis-ci.org/eddelbuettel/rcpptoml.svg)](https://travis-ci.org/eddelbuettel/rcpptoml)

Rcpp bindings for TOML

What is TOML?

TOML is a configuration file grammar for humans. It is easier to read and edit than the alternatives yet arguably more useful as it is strongly typed: values come back as integer, double, (multiline-) character (strings), boolean or Datetime. Moreover, complex nesting and arrays are supported as well.

This package uses the C++11 implementation written by Chase Geigle in cpptoml to implement a parser used by R.

Example

Consider the following TOML input example input:

# This is a TOML document.
 
title = "TOML Example"
 
[owner]
name = "Tom Preston-Werner"
dob = 1979-05-27T07:32:00-08:00 # First class dates
 
[database]
server = "192.168.1.1"
ports = [ 8001, 8001, 8002 ]
connection_max = 5000
enabled = true
 
[servers]
 
  # Indentation (tabs and/or spaces) is allowed but not required
  [servers.alpha]
  ip = "10.0.0.1"
  dc = "eqdc10"
 
  [servers.beta]
  ip = "10.0.0.2"
  dc = "eqdc10"
 
[clients]
data = [ ["gamma", "delta"], [1, 2] ]
 
# Line breaks are OK when inside arrays
hosts = [
  "alpha",
  "omega"
]

Once parsed, note how R has properly typed input:

R> library(RcppTOML)
R> parseTOML("inst/toml/example.toml")
List of 5
 $ clients :List of 2
  ..$ data :List of 2
  .. ..$ : chr [1:2] "gamma" "delta"
  .. ..$ : int [1:2] 1 2
  ..$ hosts: chr [1:2] "alpha" "omega"
 $ database:List of 4
  ..$ connection_max: int 5000
  ..$ enabled       : logi TRUE
  ..$ ports         : int [1:3] 8001 8001 8002
  ..$ server        : chr "192.168.1.1"
 $ owner   :List of 2
  ..$ dob : POSIXct[1:1], format: "1979-05-27 15:32:00"
  ..$ name: chr "Tom Preston-Werner"
 $ servers :List of 2
  ..$ alpha:List of 2
  .. ..$ dc: chr "eqdc10"
  .. ..$ ip: chr "10.0.0.1"
  ..$ beta :List of 2
  .. ..$ dc: chr "eqdc10"
  .. ..$ ip: chr "10.0.0.2"
 $ title   : chr "TOML Example"
R> 

See the other examples and the upstream documentation for more. Also note that most decent editors have proper TOML support which makes editing and previewing a breeze:

Installation

The package is on CRAN and can be installed from every mirror via

install.packages("RcppTOML")

Development releases may be provided by the ghrr repository which can accessed via

## if needed, first do:  install.packages("drat")
drat::addRepo("ghrr")

Status

Feature-complete with TOML v0.4.0, see the tests/ directory. It parses everything that the underlying cpptoml parses with the same (sole) exception of unicode escape characters in strings.

Author

Dirk Eddelbuettel

License

GPL (>= 2)