From 7168ab8fd10823e59811e9b56e2bce6d7556224a Mon Sep 17 00:00:00 2001
From: Jimmy Cuadra <jimmy@jimmycuadra.com>
Date: Thu, 23 Mar 2017 19:52:16 -0700
Subject: [PATCH] Add functions for loading parameter values from a string or
 YAML document.

---
 src/lib.rs       |  8 +++++++-
 src/parameter.rs | 50 +++++++++++++++++++++++++++++++-----------------
 2 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 4f3df66..590f13b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -79,7 +79,13 @@ extern crate regex;
 extern crate yaml_rust as yaml;
 
 pub use template::Template;
-pub use parameter::{ParameterValue, ParameterValues, parameter_values_from_file};
+pub use parameter::{
+    ParameterValue,
+    ParameterValues,
+    parameter_values_from_file,
+    parameter_values_from_str,
+    parameter_values_from_yaml,
+};
 pub use secret::{Secret, Secrets};
 
 mod parameter;
diff --git a/src/parameter.rs b/src/parameter.rs
index eeda24a..6e04f0f 100644
--- a/src/parameter.rs
+++ b/src/parameter.rs
@@ -39,42 +39,56 @@ pub type ParamMap = HashMap<String, Parameter>;
 /// A map of parameter names to user-supplied values of the parameters.
 pub type ParameterValues = HashMap<String, ParameterValue>;
 
-/// Creates a `ParameterFile` from a file.
+/// Loads `ParameterValues` from a file.
 pub fn parameter_values_from_file(file_path: &str) -> Result<ParameterValues, String> {
     let mut file = File::open(file_path).map_err(|err| err.description().to_owned())?;
 
     let mut contents = String::new();
     file.read_to_string(&mut contents).map_err(|err| err.description().to_owned())?;
 
+    parameter_values_from_str(&contents)
+}
+
+/// Loads `ParameterValues` from the raw contents of a parameter file.
+pub fn parameter_values_from_str(contents: &str) -> Result<ParameterValues, String> {
     let docs = YamlLoader::load_from_str(&contents)
         .map_err(|err| err.description().to_owned())?;
 
     let mut parameter_values = ParameterValues::new();
 
     for doc in docs {
-        match doc {
-            Yaml::Hash(ref hash) => {
-                for (key, value) in hash {
-                    match *key {
-                        Yaml::String(ref key_string) => {
-                            match *value {
-                                Yaml::String(ref value_string) => {
-                                    parameter_values.insert(
-                                        key_string.to_string(),
-                                        ParameterValue::Plain(value_string.to_string()),
-                                    );
-                                }
-                                _ => return Err("Parameter values in paramter files must be strings.".to_string()),
+        parameter_values.extend(parameter_values_from_yaml(doc)?);
+    }
+
+    Ok(parameter_values)
+}
+
+/// Loads `ParameterValues` from a YAML document in the format of a parameter file.
+pub fn parameter_values_from_yaml(yaml: Yaml) -> Result<ParameterValues, String> {
+    let mut parameter_values = ParameterValues::new();
+
+    match yaml {
+        Yaml::Hash(ref hash) => {
+            for (key, value) in hash {
+                match *key {
+                    Yaml::String(ref key_string) => {
+                        match *value {
+                            Yaml::String(ref value_string) => {
+                                parameter_values.insert(
+                                    key_string.to_string(),
+                                    ParameterValue::Plain(value_string.to_string()),
+                                );
                             }
+                            _ => return Err("Parameter values in parameter files must be strings.".to_string()),
                         }
-                        _ => return Err(
-                            "Parameters in parameter files must be strings.".to_string()
-                        ),
                     }
+                    _ => return Err(
+                        "Parameters names in parameter files must be strings.".to_string()
+                    ),
                 }
             }
-            _ => return Err("YAML documents in parameter files must be hashes.".to_string()),
         }
+        _ => return Err("YAML documents in parameter files must be hashes.".to_string()),
     }
 
     Ok(parameter_values)