393 lines
6.6 KiB
Markdown
393 lines
6.6 KiB
Markdown
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# TOML parser and encoder library for Golang [![Build Status](https://travis-ci.org/naoina/toml.png?branch=master)](https://travis-ci.org/naoina/toml)
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[TOML](https://github.com/toml-lang/toml) parser and encoder library for [Golang](http://golang.org/).
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This library is compatible with TOML version [v0.4.0](https://github.com/toml-lang/toml/blob/master/versions/en/toml-v0.4.0.md).
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## Installation
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go get -u github.com/naoina/toml
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## Usage
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The following TOML save as `example.toml`.
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```toml
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# This is a TOML document. Boom.
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title = "TOML Example"
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[owner]
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name = "Lance Uppercut"
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dob = 1979-05-27T07:32:00-08:00 # First class dates? Why not?
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[database]
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server = "192.168.1.1"
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ports = [ 8001, 8001, 8002 ]
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connection_max = 5000
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enabled = true
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[servers]
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# You can indent as you please. Tabs or spaces. TOML don't care.
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[servers.alpha]
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ip = "10.0.0.1"
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dc = "eqdc10"
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[servers.beta]
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ip = "10.0.0.2"
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dc = "eqdc10"
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[clients]
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data = [ ["gamma", "delta"], [1, 2] ]
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# Line breaks are OK when inside arrays
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hosts = [
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"alpha",
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"omega"
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]
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```
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Then above TOML will mapping to `tomlConfig` struct using `toml.Unmarshal`.
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```go
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package main
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import (
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"io/ioutil"
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"os"
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"time"
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"github.com/naoina/toml"
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)
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type tomlConfig struct {
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Title string
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Owner struct {
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Name string
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Dob time.Time
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}
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Database struct {
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Server string
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Ports []int
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ConnectionMax uint
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Enabled bool
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}
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Servers map[string]ServerInfo
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Clients struct {
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Data [][]interface{}
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Hosts []string
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}
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}
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type ServerInfo struct {
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IP net.IP
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DC string
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}
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func main() {
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f, err := os.Open("example.toml")
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if err != nil {
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panic(err)
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}
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defer f.Close()
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var config Config
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if err := toml.NewDecoder(f).Decode(&config); err != nil {
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panic(err)
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}
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// then to use the unmarshaled config...
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fmt.Println("IP of server 'alpha':", config.Servers["alpha"].IP)
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}
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```
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## Mappings
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A key and value of TOML will map to the corresponding field.
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The fields of struct for mapping must be exported.
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The rules of the mapping of key are following:
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#### Exact matching
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```toml
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timeout_seconds = 256
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```
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```go
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type Config struct {
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Timeout_seconds int
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}
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```
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#### Camelcase matching
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```toml
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server_name = "srv1"
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```
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```go
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type Config struct {
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ServerName string
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}
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```
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#### Uppercase matching
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```toml
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ip = "10.0.0.1"
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```
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```go
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type Config struct {
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IP string
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}
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```
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See the following examples for the value mappings.
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### String
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```toml
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val = "string"
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```
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```go
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type Config struct {
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Val string
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}
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```
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### Integer
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```toml
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val = 100
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```
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```go
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type Config struct {
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Val int
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}
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```
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All types that can be used are following:
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* int8 (from `-128` to `127`)
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* int16 (from `-32768` to `32767`)
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* int32 (from `-2147483648` to `2147483647`)
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* int64 (from `-9223372036854775808` to `9223372036854775807`)
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* int (same as `int32` on 32bit environment, or `int64` on 64bit environment)
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* uint8 (from `0` to `255`)
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* uint16 (from `0` to `65535`)
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* uint32 (from `0` to `4294967295`)
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* uint64 (from `0` to `18446744073709551615`)
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* uint (same as `uint` on 32bit environment, or `uint64` on 64bit environment)
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### Float
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```toml
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val = 3.1415
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```
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```go
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type Config struct {
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Val float32
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}
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```
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All types that can be used are following:
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* float32
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* float64
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### Boolean
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```toml
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val = true
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```
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```go
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type Config struct {
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Val bool
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}
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```
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### Datetime
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```toml
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val = 2014-09-28T21:27:39Z
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```
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```go
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type Config struct {
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Val time.Time
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}
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```
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### Array
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```toml
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val = ["a", "b", "c"]
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```
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```go
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type Config struct {
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Val []string
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}
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```
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Also following examples all can be mapped:
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```toml
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val1 = [1, 2, 3]
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val2 = [["a", "b"], ["c", "d"]]
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val3 = [[1, 2, 3], ["a", "b", "c"]]
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val4 = [[1, 2, 3], [["a", "b"], [true, false]]]
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```
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```go
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type Config struct {
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Val1 []int
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Val2 [][]string
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Val3 [][]interface{}
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Val4 [][]interface{}
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}
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```
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### Table
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```toml
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[server]
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type = "app"
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[server.development]
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ip = "10.0.0.1"
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[server.production]
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ip = "10.0.0.2"
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```
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```go
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type Config struct {
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Server map[string]Server
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}
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type Server struct {
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IP string
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}
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```
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You can also use the following struct instead of map of struct.
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```go
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type Config struct {
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Server struct {
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Development Server
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Production Server
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}
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}
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type Server struct {
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IP string
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}
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```
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### Array of Tables
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```toml
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[[fruit]]
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name = "apple"
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[fruit.physical]
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color = "red"
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shape = "round"
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[[fruit.variety]]
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name = "red delicious"
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[[fruit.variety]]
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name = "granny smith"
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[[fruit]]
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name = "banana"
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[[fruit.variety]]
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name = "plantain"
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```
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```go
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type Config struct {
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Fruit []struct {
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Name string
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Physical struct {
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Color string
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Shape string
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}
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Variety []struct {
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Name string
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}
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}
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}
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```
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### Using the `encoding.TextUnmarshaler` interface
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Package toml supports `encoding.TextUnmarshaler` (and `encoding.TextMarshaler`). You can
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use it to apply custom marshaling rules for certain types. The `UnmarshalText` method is
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called with the value text found in the TOML input. TOML strings are passed unquoted.
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```toml
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duration = "10s"
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```
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```go
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import time
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type Duration time.Duration
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// UnmarshalText implements encoding.TextUnmarshaler
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func (d *Duration) UnmarshalText(data []byte) error {
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duration, err := time.ParseDuration(string(data))
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if err == nil {
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*d = Duration(duration)
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}
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return err
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}
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// MarshalText implements encoding.TextMarshaler
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func (d Duration) MarshalText() ([]byte, error) {
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return []byte(time.Duration(d).String()), nil
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}
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type ConfigWithDuration struct {
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Duration Duration
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}
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```
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### Using the `toml.UnmarshalerRec` interface
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You can also override marshaling rules specifically for TOML using the `UnmarshalerRec`
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and `MarshalerRec` interfaces. These are useful if you want to control how structs or
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arrays are handled. You can apply additional validation or set unexported struct fields.
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Note: `encoding.TextUnmarshaler` and `encoding.TextMarshaler` should be preferred for
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simple (scalar) values because they're also compatible with other formats like JSON or
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YAML.
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[See the UnmarshalerRec example](https://godoc.org/github.com/naoina/toml/#example_UnmarshalerRec).
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### Using the `toml.Unmarshaler` interface
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If you want to deal with raw TOML syntax, use the `Unmarshaler` and `Marshaler`
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interfaces. Their input and output is raw TOML syntax. As such, these interfaces are
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useful if you want to handle TOML at the syntax level.
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[See the Unmarshaler example](https://godoc.org/github.com/naoina/toml/#example_Unmarshaler).
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## API documentation
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See [Godoc](http://godoc.org/github.com/naoina/toml).
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## License
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MIT
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