Merge pull request #4 from olorin37/e

Support for output option (writing to spedified file)

fixtures/data.yaml

@@ -0,0 +1,2 @@
+---
+num: 1234567899

fixtures/out.txt

@@ -0,0 +1 @@
+Cześć 1234567899.

fixtures/template.hbs

@@ -0,0 +1 @@
+Cześć {{num}}.

fixtures/test.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+
+## run it from /fixtures
+
+../target/debug/hbs-cli data.yaml template.hbs -o a.txt
+diff out.txt a.txt

src/main.rs

@@ -40,10 +40,11 @@ fn main() -> Result<(), Box<dyn Error>> {
     let data: Value = serde_yaml::from_reader(propsfile)?;
     let template = fs::read_to_string(opt.template)?;
 
-    println!(
-        "{}",
-        reg.render_template(&template, &data)?
-    );
+    let text = reg.render_template(&template, &data)?;
+    match opt.output {
+        Some(path) => fs::write(path, text)?,
+        None => println!("{}", text),
+    };
 
     Ok(())
 }