String patterns

schala-lang/language/src/eval.rs

@@ -569,6 +569,15 @@ if a { is 15 -> "x", is 10 -> "y" }
   test_in_fresh_env!(source, "\"y\"");
   }
 
+  #[test]
+  fn string_pattern() {
+    let source = r#"
+let a = "foo"
+if a { is "foo" -> "x", is _ -> "y" }
+"#;
+    test_in_fresh_env!(source, "\"x\"");
+  }
+
   #[test]
   fn boolean_pattern() {
     let source = r#"

schala-lang/language/src/reduced_ast.rs

@@ -292,7 +292,19 @@ impl PatternLiteral {
           bound_vars: vec![],
         }
       },
-      StringPattern(_s) => unimplemented!(),
+      StringPattern(s) => {
+        let guard = Some(Expr::Call {
+          f: Box::new(Expr::Func(Func::BuiltIn(Rc::new("==".to_string())))),
+          args: vec![Expr::Lit(Lit::StringLit(s.clone())), Expr::ConditionalTargetSigilValue]
+        });
+
+        Subpattern {
+          tag: None,
+          subpatterns: vec![],
+          guard,
+          bound_vars: vec![],
+        }
+      },
       BoolPattern(b) =>  {
         let guard = Some(if *b {
           Expr::ConditionalTargetSigilValue