Parse metadata tags

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

README.md

@@ -15,7 +15,14 @@ https://matthewwild.co.uk/projects/scansion/usage/script-basics/
 
 This library supports parsing the following:
 
-- [ ] Metadata
+- [x] Metadata  
+	Lines starting with `#` at the beginning of the file. All metadata lines
+	are optional. If a single line is found it's set as the title, the second
+	lines is set as the description. Lines starting with `##` right below will
+	be added as tags. A description is not needed for tags to be added.
+	- title: optional
+	- description: optional
+	- tags: optional
 - [x] Client
 	* [x] Attributes  
 		Following lines beginning with at least a tab (`\t`) character, in the

src/lib.rs

@@ -14,7 +14,7 @@ use nom::{
 	branch::alt,
 	bytes::complete::{tag, take_until, take_until1, take_while, take_while1},
 	character::complete::{digit1, multispace0, space0},
-	combinator::{opt, recognize},
+	combinator::{map_res, opt, recognize},
 	error::{ErrorKind, ParseError},
 	multi::{many0, many1},
 	sequence::{delimited, tuple},
@@ -47,11 +47,21 @@ pub static SCANSION_NS: &'static str = "https://matthewwild.co.uk/projects/scans
 pub struct Metadata {
 	pub title: String,
 	pub description: Option<String>,
+	pub tags: Vec<String>,
 }
 
 impl Metadata {
 	pub fn new<S: Into<String>, T: Into<String>>(title: S, desc: Option<T>) -> Metadata {
-		Metadata { title: title.into(), description: desc.map(|t| t.into()) }
+		Metadata {
+			title: title.into(),
+			description: desc.map(|t| t.into()),
+			tags: vec![],
+		}
+	}
+
+	pub fn with_tags(mut self, tags: Vec<String>) -> Metadata {
+		self.tags = tags;
+		self
 	}
 }
 
@@ -152,6 +162,14 @@ where
 	}
 }
 
+fn parse_meta_tags(s: Span) -> IResult<Span, Vec<String>> {
+	let (s, tags) = many0(map_res(
+		delimited(tuple((position, tag("##"))), take_until("\n"), tag("\n")),
+		|tag: Span| Ok::<String, ()>(tag.trim().to_string()),
+	))(s)?;
+	Ok((s, tags))
+}
+
 fn parse_meta(s: Span) -> IResult<Span, Metadata> {
 	let (s, (_pos, title)) =
 		tuple((position, delimited(tag("#"), take_until("\n"), tag("\n"))))(s)?;
@@ -170,7 +188,9 @@ fn parse_meta(s: Span) -> IResult<Span, Metadata> {
 		(s, None) => s,
 	};
 
-	let meta = Metadata::new(title.trim(), desc);
+	let (s, tags) = parse_meta_tags(s)?;
+
+	let meta = Metadata::new(title.trim(), desc).with_tags(tags);
 	Ok((s, meta))
 }
 
@@ -492,6 +512,8 @@ mod tests {
 	fn test_parse_spec() {
 		let buf = r#"# Test title
 # Description Foo
+## tag1
+## tag2
 
 [Client] louise
 	jid: louise@localhost
@@ -510,7 +532,10 @@ louise receives:
 
 "#;
 
-		let metadata = Some(Metadata::new("Test title", Some("Description Foo")));
+		let metadata = Some(
+			Metadata::new("Test title", Some("Description Foo"))
+				.with_tags(vec![String::from("tag1"), String::from("tag2")]),
+		);
 
 		let mut clients: HashMap<ClientName, Client> = HashMap::new();
 		clients.insert(String::from("louise"), get_client("louise"));