From d7613c8ed29730492266cf746a00243c7147ac76 Mon Sep 17 00:00:00 2001
From: Antoine Viallon <antoine@lesviallon.fr>
Date: Fri, 26 Jul 2024 01:33:00 +0200
Subject: [PATCH] lexer: fix non-stopping list() issue Convert a SystemExit to
 a CompilationError

---
 compiler/lexer.py | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/compiler/lexer.py b/compiler/lexer.py
index fececbd..6293956 100644
--- a/compiler/lexer.py
+++ b/compiler/lexer.py
@@ -7,6 +7,7 @@ import typing
 from dataclasses import dataclass, field
 from typing import cast
 
+from .errors import CompilationError
 from .logger import Logger
 from .source import SourceLocation, Location, TextIOWithMemory
 from .typechecking import typecheck
@@ -68,7 +69,7 @@ class Tokens(enum.Enum):
 class Lexer(collections.abc.Iterator):
     def __init__(self, input_stream: TextIOWithMemory, token_filter: typing.Callable[[Token], bool] | None = None):
         self.input = input_stream
-        self.tokens = []
+        self.tokens: list[Token] = []
         self.length: int | None = None
         self.begin: int = 0
         self.end: int = 0
@@ -77,6 +78,8 @@ class Lexer(collections.abc.Iterator):
         self.token_filter = token_filter
 
     def __next__(self):
+        if len(self.tokens) and self.tokens[-1].kind == Tokens.EOF:
+            raise StopIteration("EOF already reached")
         return self._filtered_next_token()
 
     def _filtered_next_token(self) -> Token:
@@ -103,6 +106,9 @@ class Lexer(collections.abc.Iterator):
         if self.tokens[-1].kind in [Tokens.BEGIN, Tokens.Newline]:
             self.input.readline()
 
+        if self.tokens[-1].kind == Tokens.EOF:
+            raise StopIteration("EOF already reached")
+
         if self.begin == len(self.input.stream_cache):
             eof_token = Token(Tokens.EOF, value=None, loc=SourceLocation(
                 Location(line=self.line, character=0),
@@ -144,8 +150,8 @@ class Lexer(collections.abc.Iterator):
             self.character += len(best_result.value)
             if best_result.kind == Tokens.Unknown:
                 source_hint = best_result.loc.show_in_source()
-                logger.error(f"{best_result.loc}: Unknown token '{best_result.loc.source_substring}'\n{source_hint}")
-                exit(1)
+                raise CompilationError(best_result.loc,
+                                       message=f"Unknown token '{best_result.loc.source_substring}'\n{source_hint}")
             elif best_result.kind == Tokens.Newline:
                 self.line += 1
                 self.character = 0
@@ -155,5 +161,3 @@ class Lexer(collections.abc.Iterator):
 
             self.tokens += [best_result]
             return best_result
-        else:
-            raise IndexError("EOF already reached")