Merge pull request 'Added String character escaping by dozenal " delimited unicode values' (#9) from feature/string-unicode-escapes into master

Reviewed-on: https://git.ablecorp.us:443/AbleScript/able-script/pulls/9

ablescript/src/lexer.rs

@@ -138,7 +138,31 @@ fn get_value<T: std::str::FromStr>(lexer: &mut Lexer<Token>) -> Option<T> {
 
 fn get_string(lexer: &mut Lexer<Token>) -> Option<String> {
     lexer.bump(lexer.remainder().find("*/")?);
-    let string = lexer.slice()[2..].to_owned();
+
+    let mut string = String::new();
+    let mut slice = &lexer.slice()[2..];
+    while let Some(escape_start) = slice.find('"') {
+        // Push predeceasing string
+        string.push_str(&slice.get(..escape_start)?);
+
+        // Move slice behind escape start delimiter
+        slice = &slice.get(escape_start + 1..)?;
+
+        // Get escape end delimiter position and parse string before it to
+        // a character from it's unicode value (base-12) and push it to string
+        let escape_end = slice.find('"')?;
+        string.push(
+            u32::from_str_radix(&slice.get(..escape_end)?, 12)
+                .ok()
+                .and_then(char::from_u32)?,
+        );
+
+        // Move slice behind escape end delimiter
+        slice = &slice.get(escape_end + 1..)?;
+    }
+
+    // Push remaining string
+    string.push_str(&slice);
     lexer.bump(2);
 
     Some(string)
@@ -179,8 +203,17 @@ mod tests {
             RightCurly,
             RightCurly,
         ];
-        let lexer = Token::lexer(code);
-        let result: Vec<Token> = lexer.collect();
+
+        let result: Vec<_> = Token::lexer(code).collect();
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn escapes() {
+        let code = r#"/*»"720B""722B""7195"«*/"#;
+        let expected = &[Token::String("»にゃぁ«".to_owned())];
+
+        let result: Vec<_> = Token::lexer(code).collect();
         assert_eq!(result, expected);
     }
 }