Change: moar parsing

1 files changed, 53 insertions, 2 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 6886727..3fa9d38 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -38,6 +38,10 @@
 //! # }
 //! ```
 
+use std::collections::HashMap;
+use serde_yaml;
+use serde_yaml::Value;
+
 /// A step in a roadmap.
 #[derive(Clone)]
 pub struct Step {
@@ -89,8 +93,30 @@ impl Roadmap {
     }
 
     /// Create a new roadmap from a YAML representation.
-    pub fn from_yaml(_yaml: &str) -> Result<Roadmap, Box<dyn std::error::Error>> {
-        Ok(Roadmap::new())
+    pub fn from_yaml(yaml: &str) -> Result<Roadmap, Box<dyn std::error::Error>> {
+        let mut roadmap = Roadmap::new();
+        let map: HashMap<String, serde_yaml::Value> = serde_yaml::from_str(yaml)?;
+
+        for (name, value) in map {
+            let step = Roadmap::step_from_value(&name, &value)?;
+            roadmap.add_step(&step)?;
+        }
+
+        Ok(roadmap)
+    }
+
+    // Convert a Value into a Step, if possible.
+    fn step_from_value(name: &str, value: &Value) -> Result<Step, &'static str> {
+        let label_key = Value::String("label".to_string());
+        match value {
+            Value::Mapping(map) => {
+                if let Some(Value::String(label)) = map.get(&label_key) {
+                    return Ok(Step::new(name, label));
+                }
+                Ok(Step::new(name, ""))
+            },
+            _ => Err("step is not a mapping"),
+        }
     }
 
     /// Return list of step names.
@@ -231,4 +257,29 @@ first -> second;
         let roadmap = Roadmap::from_yaml("{}").unwrap();
         assert_eq!(roadmap.step_names().len(), 0);
     }
+
+    #[test]
+    fn from_nonempty_yaml() {
+        let mut roadmap = Roadmap::from_yaml("
+first:
+  label: the first step
+second:
+  label: the second step
+  depends:
+  - first
+").unwrap();
+
+        let names = roadmap.step_names();
+        assert_eq!(names.len(), 2);
+        assert!(names.contains(&"first"));
+        assert!(names.contains(&"second"));
+
+        let first = roadmap.get_step("first").unwrap();
+        assert_eq!(first.name(), "first");
+        assert_eq!(first.label(), "the first step");
+
+        let second = roadmap.get_step("second").unwrap();
+        assert_eq!(second.name(), "second");
+        assert_eq!(second.label(), "the second step");
+    }
 }