Add a toml to json example

examples/toml2json.rs

@@ -0,0 +1,57 @@
+#![deny(warnings)]
+
+extern crate toml;
+extern crate rustc_serialize;
+
+use std::fs::File;
+use std::env;
+use std::io;
+use std::io::prelude::*;
+
+use toml::Value;
+use rustc_serialize::json::Json;
+
+fn main() {
+    let mut args = env::args();
+    let mut input = String::new();
+    let filename = if args.len() > 1 {
+        let name = args.nth(1).unwrap();
+        File::open(&name).and_then(|mut f| {
+            f.read_to_string(&mut input)
+        }).unwrap();
+        name
+    } else {
+        io::stdin().read_to_string(&mut input).unwrap();
+        "<stdin>".to_string()
+    };
+
+    let mut parser = toml::Parser::new(&input);
+    let toml = match parser.parse() {
+        Some(toml) => toml,
+        None => {
+            for err in &parser.errors {
+                let (loline, locol) = parser.to_linecol(err.lo);
+                let (hiline, hicol) = parser.to_linecol(err.hi);
+                println!("{}:{}:{}-{}:{} error: {}",
+                         filename, loline, locol, hiline, hicol, err.desc);
+            }
+            return
+        }
+    };
+    let json = convert(Value::Table(toml));
+    println!("{}", json.pretty());
+}
+
+fn convert(toml: Value) -> Json {
+    match toml {
+        Value::String(s) => Json::String(s),
+        Value::Integer(i) => Json::I64(i),
+        Value::Float(f) => Json::F64(f),
+        Value::Boolean(b) => Json::Boolean(b),
+        Value::Array(arr) => Json::Array(arr.into_iter().map(convert).collect()),
+        Value::Table(table) => Json::Object(table.into_iter().map(|(k, v)| {
+            (k, convert(v))
+        }).collect()),
+        Value::Datetime(dt) => Json::String(dt),
+    }
+}