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//! A library to parse and load configuration files. //! //! This library parses and loads configuration files in much the same way as C/C++'s //! [libconfig](http://www.hyperrealm.com/libconfig/). At this time, it can only read and load //! configurations, but future plans include a much richer user API to allow other forms of //! interaction, such as manipulating values, writing the current configuration to a file, etc. //! //!# Getting started //! //! A configuration file consists of a group of settings. A setting is a key/value pair, where the //! key is a string of the form `[a-zA-Z][-a-zA-Z0-9_]*`, and the value is anything represented by //! `types::Value`. In a configuration file, setting/value pairs are written as //! `setting_name = value;`. Possible values include primitive integer and floating point types, //! strings, arrays, lists, etc. //! //! The library provides a bunch of methods to read the configuration data in the `reader` module. //! The possibilities include reading from a string, from a file, or from anything that implements //! the `Read` trait. //! //! As of now, every reader will first attempt to read the whole configuration into memory, //! and only begins parsing once everything was read. //! //! In case of error, the parser returns a `config::error`. //! On success, the parser returns a `Config`, which can then be used to browse the loaded data. //! //! Browsing is typically done with the `lookup_*` methods implemented by `Config`. The `lookup` //! methods work with *paths*. Essentially, a path unambiguously describes the location of //! a setting. //! //! For example, consider this input configuration file: //! //!```ignore //! title = "My HTTP server"; //! listen_ports = [ 80, 443 ]; //! misc = { //! owner = "Chuck Norris"; //! location = "CA"; //! contact = { //! phone = "415-256-9999"; //! // This is an array. Arrays start with `[` and end with `]` //! // Arrays are homogeneous and can only hold scalar data types. //! // See types::ScalarValue for further information //! emails = ["chuck@norris.com", "chuck.norris@gmail.com"]; //! }; //! }; //!``` //! //! At the top level, we have 3 settings: `title`, `listen_ports` and `misc`. `misc` is itself a //! group of settings. Each value in this configuration is reachable by a unique path of settings //! to follow. Each setting in a path is separated by `.` //! //! **Example**: The path `misc.contact.phone` identifies the setting with value `415-256-9999`. //! //! Array and list types are indexed using `[i]` in a path. //! //! **Example**: The path `listen_ports.[1]` identifies the setting with value `443`. //! //! **Example**: The path `misc.contact.emails.[0]` identifies the setting with value //! `chuck@norris.com` //! //! Lists, as opposed to arrays, are heterogeneous and can store any data type, including other //! lists. Here's a setting consisting of a heterogeneous list: //! //!```ignore //! // This is a list. Lists start with `(` and end with `)` //! // Lists are heterogeneous and can store any data type, including other lists //! a_setting = ("a string", // The first element is a string //! ((1, 2, 3)), // The 2nd element is a list storing a list of 3 integers //! misc = { x = 4; y = 3; } // 3rd element: a group //! ); //!``` //! //! Here are some valid paths for this example: //! //! `a_setting.[0]` - returns the string `a string` //! //! `a_setting.[1].[0].[2]` - returns the integer `3` //! //! `a_setting.[2].misc.x` - returns the integer `4` //! //! Adjacent string literals separated by whitespace, newlines and / or comments are automatically //! concatenated. //! //! **Example**: //! //! ```ignore //! "a"/* a comment */" string" " liter" //! //! // This is a commment //! //! "al" //! ``` //! //! is equivalent to: //! //! ```ignore //! "a string literal" //! ``` //! //! See the integration tests (in the `tests/` directory) for sample use cases and more complex //! examples. //! //!# Environment variables //! //! The crate has an ability to inject environment variables into the configuration file. That //! becomes possible using special syntax: //! //! * `$"SOME_ENV_VAR_NAME"::str` to inject the environment variables `SOME_ENV_VAR_NAME` as the string value. //! No additiocal changes are made ot the value. //! * `$"SOME_ENV_VAR_NAME"::bool` to inject the environment variable `SOME_ENV_VAR_NAME` as the boolean value. //! The value `true` or `yes` or `on` or `1` are converted into `true` otherwise into `false`. //! * `$"SOME_ENV_VAR_NAME"::int` to inject the environment variable `SOME_ENV_VAR_NAME` as the integer value. //! The successfully parsed value is injected as `i32` or `i64`, depending on the format, otherwise `0i32` is injected. //! * `$"SOME_ENV_VAR_NAME"::flt` to inject the environment variable `SOME_ENV_VAR_NAME` as the floating value. //! The successfully parsed value is injected as `f32` or `f64`, depending on the format, otherwise `0f32` is injected. //! * `$"SOME_ENV_VAR_NAME"::auto` or `$"SOME_ENV_VAR_NAME"` to inject the environment variable `SOME_ENV_VAR_NAME` //! and resolve the type automatically. Rules of the type auto-resolution: //! - If the value is *True* or *Yes* or *On* then the result type is `boolean True`; //! - If the value is *False* or *No* or *Off* then the result type is `boolean False`; //! - If the value is floating then the result type is `floating`; //! - If the value is integer then the result type is `integer`; //! - Otherwise the result is `string` value. //! //!**Example**: //! //! ```ignore //! #!/bin/sh //! export LOG_LEVEL=debug //! ``` //! //! ```ignore //! // Configuration file //! log = { //! // Inject (use) the value of the environment variable LOG_LEVEL //! level = $"LOG_LEVEL"::str; //! } //! ``` //! //!# Grammar //! //! This section describes the configuration input format. The starting rule is `conf`. //! //! ```text //! conf -> __ settings_list __ //! //! settings_list -> // empty //! | setting settings_list //! setting -> __ name __ (":"|"=") __ value __ ";" __ //! //! name -> [a-zA-Z][-a-zA-Z0-9_]* //! //! value -> scalar_value //! | array_value //! | list_value //! | group_value //! //! scalar_value -> boolean_scalar_value //! | floating64_scalar_value //! | floating32_scalar_value //! | integer64_scalar_value //! | integer32_scalar_value //! | str_scalar_value //! | auto_env_scalar_value //! //! boolean_scalar_value -> [Tt][Rr][Uu][Ee] //! | [Yy][Ee][Ss] //! | [Oo][Nn] //! | [Ff][Aa][Ll][Ss][Ee] //! | [Nn][Oo] //! | [Oo][Ff][Ff] //! | $"ENV_VAR_NAME"::bool //! //! floating64_scalar_value -> [+-]?([0-9]+\.[0-9]*|\.[0-9]+)([eE][+-]?[0-9]+)?"L" //! | $"ENV_VAR_NAME"::flt //! //! floating32_scalar_value -> [+-]?([0-9]+\.[0-9]*|\.[0-9]+)([eE][+-]?[0-9]+)? //! | $"ENV_VAR_NAME"::flt //! //! integer32_scalar_value -> [+-]?[0-9]+ //! | $"ENV_VAR_NAME"::int //! //! integer64_scalar_value -> [+-]?[0-9]+"L" //! | $"ENV_VAR_NAME"::int //! //! str_scalar_value -> __ str_literal __ //! | __ str_literal __ str_scalar_value //! | $"ENV_VAR_NAME"::str //! //! auto_env_scalar_value -> $"ENV_VAR_NAME"::auto //! | $"ENV_VAR_NAME" //! //! str_literal -> "\"" ([^\"\\]|(("\\r"|"\\n"|"\\t"|"\\\""|"\\\\")))* "\"" //! //! array_value -> "[" //! (bool_array | //! flt64_array | flt32_array | //! int64_array | int32_array | //! str_array) //! "]" //! | "[" __ "]" //! //! bool_array -> __ boolean_scalar_value __ //! | __ boolean_scalar_value __ "," __ bool_array //! //! flt64_array -> __ floating64_scalar_value __ //! | __ floating64_scalar_value __ "," __ flt64_array //! //! flt32_array -> __ floating32_scalar_value __ //! | __ floating32_scalar_value __ "," __ flt32_array // //! int64_array -> __ integer64_scalar_value __ //! | __ integer64_scalar_value __ "," __ int64_array //! //! int32_array -> __ integer32_scalar_value __ //! | __ integer32_scalar_value __ "," __ int32_array //! //! str_array -> __ str_scalar_value __ //! | __ str_scalar_value __ "," __ str_array //! //! list_value -> "(" __ ")" //! | "(" list_elements ")" //! //! list_elements -> __ value __ //! | __ value __ "," __ list_elements //! //! group_value -> "{" settings_list "}" //! //! __ -> // empty //! | whitespace __ //! | eol __ //! | comment __ //! //! whitespace -> [\s\t] //! //! eol -> "\r\n" //! | "\n" //! //! comment -> single_line_comment //! | multi_line_comment //! //! single_line_comment -> ("//"|"#")[^\n]*"\n"? //! //! multi_line_comment -> "/*"([^*]|"*"[^/])*"*/" //! //! ``` //! #![crate_name = "libconfig"] #![crate_type = "lib"] #![warn(missing_docs)] #[macro_use] extern crate nom; mod parser; pub mod types; pub mod error; pub mod reader;