Add embedded struct output support for flags.

We use a dotted syntax for now but we might want to support other
separators in a future commit.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name        = "ucg"
-version     = "0.0.1"
+version     = "0.0.2"
 authors     = ["Jeremy Wall <jeremy@marzhillstudios.com>"]
 description = "A configuration generation grammar."
 repository  = "https://github.com/zaphar/ucg"

TODO.md

@@ -17,4 +17,6 @@ organiztion for a given configuration structure. Some options here could be
 
 # Minor Fixes and Polish
 
+* Flags should allow different seperators for prefixed flags.
+* None value types
 * YAML export

examples/env.txt

@@ -1 +0,0 @@
-dbconn_list=db_conn1='db1.prod.net:3306/testdb' db_conn2='db2.prod.net:3306/testdb' tmpldir='./templates' 

examples/flags.txt

@@ -1 +0,0 @@
---db_conn1 'db1.prod.net:3306/testdb' --db_conn2 'db2.prod.net:3306/testdb' --dbconn_list --tmpldir './templates' 

examples/test.ucg

@@ -19,8 +19,10 @@ let db_conns = [db_conn1.conn_string, db_conn2.conn_string];
 
 // Our server configuration.
 let server_config = {
-    dbconn_list = db_conns,
     db_conn1 = db_conns.0, // connection one
     db_conn2 = db_conns.1,
-    tmpldir = "./templates"
+    tmpldir = "./templates",
+    prefix = {
+        foo = "bar"
+    }
 };

src/ast.rs

@@ -437,6 +437,12 @@ pub struct Positioned<T> {
     pub val: T,
 }
 
+impl<T: std::fmt::Display> std::fmt::Display for Positioned<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+        write!(f, "{}", self.val)
+    }
+}
+
 impl<T> Positioned<T> {
     /// Constructs a new Positioned<T> with a value, line, and column information.
     pub fn new(v: T, l: usize, c: usize) -> Self {

src/convert/flags.rs

@@ -28,7 +28,7 @@ impl FlagConverter {
         FlagConverter {}
     }
 
-    fn write(&self, v: &Val, w: &mut Write) -> Result<()> {
+    fn write(&self, pfx: &str, v: &Val, w: &mut Write) -> Result<()> {
         match v {
             &Val::Float(ref f) => {
                 try!(write!(w, "{} ", f));
@@ -46,12 +46,17 @@ impl FlagConverter {
             &Val::Tuple(ref flds) => {
                 for &(ref name, ref val) in flds.iter() {
                     if val.is_tuple() {
-                        eprintln!("Skipping embedded tuple...");
-                        return Ok(());
+                        let new_pfx = format!("{}{}.", pfx, name);
+                        try!(self.write(&new_pfx, val, w));
+                    } else {
+                        if name.val.chars().count() > 1 || pfx.chars().count() > 0 {
+                            try!(write!(w, "--{}{} ", pfx, name.val));
+                        } else {
+                            try!(write!(w, "-{} ", name.val));
+                        }
+                        // TODO(jwall): What if the value is a tuple?
+                        try!(self.write(pfx, &val, w));
                     }
-                    try!(write!(w, "--{} ", name.val));
-                    // TODO(jwall): What if the value is a tuple?
-                    try!(self.write(&val, w));
                 }
             }
             &Val::Macro(ref _def) => {
@@ -65,6 +70,6 @@ impl FlagConverter {
 
 impl Converter for FlagConverter {
     fn convert(&self, v: Rc<Val>, mut w: Box<Write>) -> Result<()> {
-        self.write(&v, &mut w)
+        self.write("", &v, &mut w)
     }
 }