Spralja/issue 33

src/errors/__init__.py

@@ -0,0 +1,40 @@
+
+
+class BaseError(Exception):
+    def __init__(self, message):
+        super().__init__(message)
+
+    @property
+    def traceback(self):
+        return self._traceback
+
+
+class SyntaxError(BaseError):
+    def __init__(self, message, tokens, current):
+        self.tokens = tokens
+        self.current = current
+        super().__init__(message)
+
+    def __str__(self):
+        string = ''
+        current_token = self.tokens[self.current]
+        current_line = current_token.line
+
+        start_of_line = self.current
+        while start_of_line > 0 and self.tokens[start_of_line].line == current_line:
+            start_of_line -= 1
+
+        end_of_line = self.current
+        while end_of_line < len(self.tokens) and self.tokens[end_of_line].line == current_line:
+            end_of_line += 1
+
+
+        for token, index in zip(self.tokens[start_of_line:end_of_line], range(start_of_line, end_of_line)):
+            if index == self.current:
+                string += '~~ '
+            string += token.lexeme + ' '
+
+            if index == self.current:
+                string += '~~'
+
+        return string

src/pychart/runner.py

@@ -1,24 +1,28 @@
 from src.scanner import Scanner
 from src.pyparser import Parser
+from src import errors
 
 
 def run(source: str):
-    scanner = Scanner(source)
-    tokens = scanner.get_tokens()
-    ast = Parser(tokens).parse()
+    try:
+        scanner = Scanner(source)
+        tokens = scanner.get_tokens()
+        ast = Parser(tokens).parse()
 
-    if ast is None:
-        return
+        if ast is None:
+            return
 
-    value = ast()
+        value = ast()
 
-    try:
-        value = int(value)
-    except:
-        pass
+        try:
+            value = int(value)
+        except:
+            pass
 
-    # print(f"AST: {ast}")
-    print(value)
+        # print(f"AST: {ast}")
+        print(value)
+    except errors.BaseError as e:
+        print(e)
 
 
 def run_prompt():