Nicer error messages for unknown tokens (#974)

src/wasm-lib/kcl/src/parser.rs

@@ -36,13 +36,13 @@ impl Parser {
 
         if !self.unknown_tokens.is_empty() {
             let source_ranges = self.unknown_tokens.iter().map(SourceRange::from).collect();
-            return Err(KclError::Lexical(KclErrorDetails {
-                source_ranges,
-                message: format!(
-                    "found unknown tokens {:?}",
-                    self.unknown_tokens.iter().map(|t| t.value.as_str()).collect::<Vec<_>>()
-                ),
-            }));
+            let token_list = self.unknown_tokens.iter().map(|t| t.value.as_str()).collect::<Vec<_>>();
+            let message = if token_list.len() == 1 {
+                format!("found unknown token '{}'", token_list[0])
+            } else {
+                format!("found unknown tokens [{}]", token_list.join(", "))
+            };
+            return Err(KclError::Lexical(KclErrorDetails { source_ranges, message }));
         }
 
         parser_impl::run_parser(&mut self.tokens.as_slice())

src/wasm-lib/kcl/src/parser/parser_impl.rs

@@ -2214,9 +2214,10 @@ const secondExtrude = startSketchOn('XY')
         let tokens = crate::token::lexer(">!");
         let parser = crate::parser::Parser::new(tokens);
         let err = parser.ast().unwrap_err();
-        // TODO: Better errors when program cannot tokenize.
-        // https://github.com/KittyCAD/modeling-app/issues/696
-        assert!(err.to_string().contains("found list of unknown tokens"));
+        assert_eq!(
+            err.to_string(),
+            r#"lexical: KclErrorDetails { source_ranges: [SourceRange([1, 2])], message: "found unknown token '!'" }"#
+        );
     }
 
     #[test]
@@ -2272,11 +2273,9 @@ z(-[["#,
         let parser = crate::parser::Parser::new(tokens);
         let result = parser.ast();
         assert!(result.is_err());
-        // TODO: Better errors when program cannot tokenize.
-        // https://github.com/KittyCAD/modeling-app/issues/696
         assert_eq!(
             result.err().unwrap().to_string(),
-            r##"lexical: KclErrorDetails { source_ranges: [SourceRange([6, 7])], message: "found list of unknown tokens \"#\"" }"##
+            r#"lexical: KclErrorDetails { source_ranges: [SourceRange([6, 7])], message: "found unknown token '#'" }"#
         );
     }
 
@@ -2286,11 +2285,9 @@ z(-[["#,
         let parser = crate::parser::Parser::new(tokens);
         let result = parser.ast();
         assert!(result.is_err());
-        // TODO: Better errors when program cannot tokenize.
-        // https://github.com/KittyCAD/modeling-app/issues/696
         assert_eq!(
             result.err().unwrap().to_string(),
-            r##"lexical: KclErrorDetails { source_ranges: [SourceRange([25, 26]), SourceRange([26, 27])], message: "found list of unknown tokens \"# #\"" }"##
+            r#"lexical: KclErrorDetails { source_ranges: [SourceRange([25, 26]), SourceRange([26, 27])], message: "found unknown tokens [#, #]" }"#
         );
     }