Add [ATTRIBUTE: VALUE] shorthand (#2136)

src/attribute.rs

@@ -57,9 +57,7 @@ impl<'src> Attribute<'src> {
       })?;
 
     let found = argument.as_ref().iter().count();
-
     let range = discriminant.argument_range();
-
     if !range.contains(&found) {
       return Err(
         name.error(CompileErrorKind::AttributeArgumentCountMismatch {

src/parser.rs

@@ -987,15 +987,18 @@ impl<'run, 'src> Parser<'run, 'src> {
       loop {
         let name = self.parse_name()?;
 
-        let argument = if self.accepted(ParenL)? {
+        let maybe_argument = if self.accepted(Colon)? {
-          let argument = self.parse_string_literal()?;
+          let arg = self.parse_string_literal()?;
+          Some(arg)
+        } else if self.accepted(ParenL)? {
+          let arg = self.parse_string_literal()?;
           self.expect(ParenR)?;
-          Some(argument)
+          Some(arg)
         } else {
           None
         };
 
-        let attribute = Attribute::new(name, argument)?;
+        let attribute = Attribute::new(name, maybe_argument)?;
 
         if let Some(line) = attributes.get(&attribute) {
           return Err(name.error(CompileErrorKind::DuplicateAttribute {
@@ -1158,6 +1161,18 @@ mod tests {
     tree: (justfile (alias t test)),
   }
 
+  test! {
+    name: single_argument_attribute_shorthand,
+    text: "[group: 'some-group']\nalias t := test",
+    tree: (justfile (alias t test)),
+  }
+
+  test! {
+    name: single_argument_attribute_shorthand_multiple_same_line,
+    text: "[group: 'some-group', group: 'some-other-group']\nalias t := test",
+    tree: (justfile (alias t test)),
+  }
+
   test! {
     name: aliases_multiple,
     text: "alias t := test\nalias b := build",

tests/attributes.rs

@@ -72,7 +72,7 @@ fn multiple_attributes_one_line_error_message() {
     )
     .stderr(
       "
-        error: Expected ']', ',', or '(', but found identifier
+        error: Expected ']', ':', ',', or '(', but found identifier
          ——▶ justfile:1:17
           │
         1 │ [macos, windows linux]

tests/groups.rs

@@ -144,3 +144,26 @@ fn list_groups_with_custom_prefix() {
     )
     .run();
 }
+
+#[test]
+fn list_groups_with_shorthand_syntax() {
+  Test::new()
+    .justfile(
+      "
+        [group: 'B']
+        foo:
+
+        [group: 'A', group: 'B']
+        bar:
+      ",
+    )
+    .args(["--groups", "--list-prefix", "..."])
+    .stdout(
+      "
+      Recipe groups:
+      ...A
+      ...B
+      ",
+    )
+    .run();
+}