FEATURE: Add toml as an output converter.

closes #4

Cargo.lock

@@ -224,6 +224,14 @@ dependencies = [
  "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "toml"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "serde 1.0.75 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ucg"
 version = "0.2.3"
@@ -235,6 +243,7 @@ dependencies = [
  "serde_json 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_yaml 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "simple-error 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "toml 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -316,6 +325,7 @@ dependencies = [
 "checksum term_size 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "9e5b9a66db815dcfd2da92db471106457082577c3c278d4138ab3e3b4e189327"
 "checksum termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "689a3bdfaab439fd92bc87df5c4c78417d3cbe537487274e9b0b2dce76e92096"
 "checksum textwrap 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df8e08afc40ae3459e4838f303e465aa50d823df8d7f83ca88108f6d3afe7edd"
+"checksum toml 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)" = "4a2ecc31b0351ea18b3fe11274b8db6e4d82bce861bbb22e6dbed40417902c65"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"

Cargo.toml

@@ -15,6 +15,7 @@ clap         = "~2.26.0"
 serde_json   = "~1.0.9"
 simple-error = "0.1"
 serde_yaml = "~0.8.1"
+toml = "~0.4.8"
 
 [dev-dependencies]
 bencher = "~0.1.5"

examples/test_toml.ucg

@@ -0,0 +1,12 @@
+let config = {
+    format = "toml",
+    app = {
+        name = "app",
+        version = "v0.0.0",
+    },
+    metadata = {
+        tags = ["foo", "bar"],
+    },
+};
+
+out toml config;

src/convert/mod.rs

@@ -17,6 +17,7 @@ pub mod env;
 pub mod exec;
 pub mod flags;
 pub mod json;
+pub mod toml;
 pub mod traits;
 pub mod yaml;
 
@@ -47,6 +48,7 @@ impl ConverterRegistry {
         registry.register("flags", Box::new(flags::FlagConverter::new()));
         registry.register("exec", Box::new(exec::ExecConverter::new()));
         registry.register("yaml", Box::new(yaml::YamlConverter::new()));
+        registry.register("toml", Box::new(toml::TomlConverter::new()));
         registry
     }
 

src/convert/toml.rs

@@ -0,0 +1,94 @@
+// Copyright 2018 Jeremy Wall
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std;
+use std::error;
+use std::io::Write;
+use std::rc::Rc;
+
+use simple_error::SimpleError;
+use toml;
+
+use ast;
+use build::Val;
+use convert::traits::{Converter, Result};
+
+pub struct TomlConverter {}
+
+type ConvertResult = std::result::Result<toml::Value, Box<error::Error>>;
+
+impl TomlConverter {
+    pub fn new() -> Self {
+        TomlConverter {}
+    }
+
+    fn convert_list(&self, items: &Vec<Rc<Val>>) -> ConvertResult {
+        let mut v = Vec::new();
+        for val in items.iter() {
+            v.push(try!(self.convert_value(val)));
+        }
+        Ok(toml::Value::Array(v))
+    }
+
+    fn convert_tuple(&self, items: &Vec<(ast::PositionedItem<String>, Rc<Val>)>) -> ConvertResult {
+        let mut mp = toml::value::Table::new();
+        for &(ref k, ref v) in items.iter() {
+            mp.entry(k.val.clone())
+                .or_insert(try!(self.convert_value(v)));
+        }
+        Ok(toml::Value::Table(mp))
+    }
+
+    fn convert_value(&self, v: &Val) -> ConvertResult {
+        let toml_val = match v {
+            &Val::Boolean(b) => toml::Value::Boolean(b),
+            // TODO(jwall): This is an error apparently
+            &Val::Empty => {
+                let err = SimpleError::new("Nulls are not allowed in Toml Conversions!");
+                return Err(Box::new(err));
+            }
+            &Val::Float(f) => toml::Value::Float(f),
+            &Val::Int(i) => toml::Value::Integer(i),
+            &Val::Str(ref s) => toml::Value::String(s.clone()),
+            &Val::Macro(_) => {
+                let err = SimpleError::new("Macros are not allowed in Toml Conversions!");
+                return Err(Box::new(err));
+            }
+            &Val::List(ref l) => try!(self.convert_list(l)),
+            &Val::Tuple(ref t) => try!(self.convert_tuple(t)),
+        };
+        Ok(toml_val)
+    }
+
+    fn write(&self, v: &Val, w: &mut Write) -> Result {
+        let toml_val = try!(self.convert_value(v));
+        let toml_bytes = try!(toml::ser::to_string_pretty(&toml_val));
+        try!(write!(w, "{}", toml_bytes));
+        Ok(())
+    }
+}
+
+impl Converter for TomlConverter {
+    fn convert(&self, v: Rc<Val>, mut w: &mut Write) -> Result {
+        self.write(&v, &mut w)
+    }
+
+    fn file_ext(&self) -> String {
+        String::from("toml")
+    }
+
+    fn description(&self) -> String {
+        "Convert ucg Vals into valid ucg.".to_string()
+    }
+}

src/lib.rs

@@ -40,7 +40,7 @@
 //!
 //! ## Syntax
 //!
-//! A valid ucg file is composesed of a series of statements. Stataments start with an
+//! A valid ucg file is composed of a series of statements. Statements start with an
 //! optional keyword and terminate with a semicolon.
 //!
 //! ### Reserved words
@@ -488,6 +488,7 @@ extern crate abortable_parser;
 extern crate serde_json;
 extern crate serde_yaml;
 extern crate simple_error;
+extern crate toml;
 
 #[macro_use]
 pub mod ast;