yaml: add YamlLoader::load_from_parser(&Parser)

Make it easier to load documents from a prebuilt Parser.

parser/CHANGELOG.md

@@ -30,6 +30,8 @@ using that feature.
 - `YamlLoader` structs now have a `documents()` method that returns the parsed
 documents associated with a loader.
 
+- `Parser::new_from_str(&str)` and `YamlLoader::load_from_parser(&Parser)` were added.
+
 **Development**:
 
 ## v0.7.0

parser/src/parser.rs

@@ -1126,17 +1126,18 @@ foo: "bar"
 --- !t!2 &2
 baz: "qux"
 "#;
-        let mut loader = YamlLoader::default();
-        let mut parser = Parser::new(text.chars()).keep_tags(true);
-        assert!(parser.load(&mut loader, true).is_ok());
-        assert_eq!(loader.documents().len(), 2);
-        let yaml = &loader.documents()[0];
+        let mut parser = Parser::new_from_str(text).keep_tags(true);
+        let result = YamlLoader::load_from_parser(&mut parser);
+        assert!(result.is_ok());
+        let docs = result.unwrap();
+        assert_eq!(docs.len(), 2);
+        let yaml = &docs[0];
         assert_eq!(yaml["foo"].as_str(), Some("bar"));
-        let yaml = &loader.documents()[1];
+        let yaml = &docs[1];
         assert_eq!(yaml["baz"].as_str(), Some("qux"));
 
-        let mut loader = YamlLoader::default();
-        let mut parser = Parser::new(text.chars()).keep_tags(false);
-        assert!(parser.load(&mut loader, true).is_err());
+        let mut parser = Parser::new_from_str(text).keep_tags(false);
+        let result = YamlLoader::load_from_parser(&mut parser);
+        assert!(result.is_err());
     }
 }

parser/src/yaml.rs

@@ -234,8 +234,20 @@ impl YamlLoader {
     /// # Errors
     /// Returns `ScanError` when loading fails.
     pub fn load_from_iter<I: Iterator<Item = char>>(source: I) -> Result<Vec<Yaml>, ScanError> {
-        let mut loader = YamlLoader::default();
         let mut parser = Parser::new(source);
+        Self::load_from_parser(&mut parser)
+    }
+
+    /// Load the contents from the specified Parser as a set of YAML documents.
+    ///
+    /// Parsing succeeds if and only if all documents are parsed successfully.
+    /// An error in a latter document prevents the former from being returned.
+    /// # Errors
+    /// Returns `ScanError` when loading fails.
+    pub fn load_from_parser<I: Iterator<Item = char>>(
+        parser: &mut Parser<I>,
+    ) -> Result<Vec<Yaml>, ScanError> {
+        let mut loader = YamlLoader::default();
         parser.load(&mut loader, true)?;
         Ok(loader.docs)
     }