lexer: rename tokenizer to lexer, and convert to sequence

compiler/__main__.py

@@ -8,7 +8,7 @@ from . import semantic
 from .errors import CompilationError
 from .logger import rootLogger, LogLevel
 from .parser import Parser
-from .tokenizer import Tokenizer, Tokens
+from .lexer import Lexer, Tokens
 
 
 def main():
@@ -32,8 +32,7 @@ def main():
         data = sys.stdin.read().strip()
 
     print("Source:\n", data)
-    tokenizer = Tokenizer()
-    tokens = tokenizer.tokenize(data)
+    tokens = Lexer(data)
 
     tokens = [token for token in tokens if token.kind not in [Tokens.Blank, Tokens.Newline]]
     if rootLogger.level <= LogLevel.Debug:

compiler/errors.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 import inspect
 
-from . import source, tokenizer
+from . import source, lexer
 
 
 class CompilationError(Exception):
@@ -12,9 +12,9 @@ class CompilationError(Exception):
 
 
 class UnexpectedTokenError(CompilationError):
-    def __init__(self, got: tokenizer.Token, wanted: tokenizer.Tokens | str):
+    def __init__(self, got: lexer.Token, wanted: lexer.Tokens | str):
         message = wanted
-        if type(wanted) == tokenizer.Tokens:
+        if type(wanted) == lexer.Tokens:
             message = str(wanted)
         super().__init__(got.loc, f"Unexpected token '{got}', wanted {message}")
 

compiler/lexer.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import collections.abc
 import enum
 import re
 from dataclasses import dataclass, field
@@ -47,52 +48,76 @@ class Tokens(enum.Enum):
         return True
 
 
-class Tokenizer:
-    def __init__(self):
-        pass
+class Lexer(collections.abc.Sequence):
+    def __init__(self, data: str):
+        self.data = data
+        self.tokens = []
+        self.length: int | None = None
+        self.begin: int = 0
+        self.end: int = 0
+        self.character: int = 0
+        self.line: int = 0
 
-    def tokenize(self, data: str) -> List[Token]:
-        results: List[Token] = []
-        line = 0
-        character = 0
-        begin = 0
-        while begin < len(data):
+    def __getitem__(self, index: int) -> Token:
+        while len(self) <= index + 1 and self.length is None:
+            self._next_token()
+        return self.tokens[index]
+
+    def __next__(self):
+        return self._next_token()
+
+    def __len__(self) -> int:
+        while self.length is None:
+            self._next_token()
+
+        assert self.length is not None
+
+        return self.length
+
+    def _next_token(self) -> Token:
+        actual_result: Token
+        if self.begin < len(self.data):
             best_result: Token = Token(Tokens.Unknown,
-                                       loc=SourceLocation(Location(line=line, character=character), source=data),
+                                       loc=SourceLocation(Location(line=self.line, character=self.character), source=self.data),
                                        value=""
                                        )
             for token_kind in list(Tokens):
                 if token_kind == Tokens.Unknown:
                     continue
                 regex: re.Pattern = token_kind.value
-                match = regex.match(data, begin)
+                match = regex.match(self.data, self.begin)
                 if match is not None:
                     logger.trace(f"Got match: {match}")
                     result = match.group(0)
                     if best_result.kind == Tokens.Unknown or len(result) >= len(best_result.value):
                         loc = SourceLocation(
-                            begin=Location(line=line, character=character),
-                            end=Location(line=line, character=character + len(result))
+                            begin=Location(line=self.line, character=self.character),
+                            end=Location(line=self.line, character=self.character + len(result))
                         )
                         best_result = Token(token_kind, value=result, loc=loc)
                         logger.trace(f"New best match: {best_result}")
 
-            begin += len(best_result.value)
-            character += len(best_result.value)
+            self.begin += len(best_result.value)
+            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)
             elif best_result.kind == Tokens.Newline:
-                line += 1
-                character = 0
-                best_result.loc.end = Location(line=line, character=0)
+                self.line += 1
+                self.character = 0
+                best_result.loc.end = Location(line=self.line, character=0)
 
             logger.debug(f"Added token {best_result}")
 
-            results += [best_result]
-
-        results += [Token(Tokens.EOF, value=None, loc=SourceLocation(
-            Location(line=line, character=0), source=data
-        ))]
-        return results
+            self.tokens += [best_result]
+            return best_result
+        elif self.begin == len(self.data):
+            eof_token = Token(Tokens.EOF, value=None, loc=SourceLocation(
+                Location(line=self.line, character=0), source=self.data
+            ))
+            self.tokens += [eof_token]
+            self.length = len(self.tokens)
+            return eof_token
+        else:
+            raise IndexError("EOF already reached")

compiler/nodes.py

@@ -6,7 +6,7 @@ from typing import Any, Iterable
 
 from beartype import beartype
 
-from . import ir, semantic, tokenizer
+from . import ir, semantic, lexer
 from .errors import SemanticAnalysisError, OverrideMandatoryError
 from .logger import Logger
 from .source import SourceLocation
@@ -116,7 +116,7 @@ class PseudoNode(Literal):
     Only used for better diagnostics
     """
 
-    def __init__(self, token: tokenizer.Token):
+    def __init__(self, token: lexer.Token):
         super().__init__(token.loc, token.value)
         self.token = token
 

compiler/parser.py

@@ -6,11 +6,12 @@ from .errors import CompilationError, UnexpectedTokenError
 from .logger import Logger, Tracer, LogLevel
 from .nodes import Float, Sum, Value, Product, Node, Division, Sub, Integer, Expression, Identifier, Assignment, \
     Variable, Statement, PseudoNode, Block
-from .tokenizer import Tokens, Token
+from .lexer import Tokens, Token
 
 logger = Logger(__name__)
 tracer = Tracer(logger, level=LogLevel.Debug)
 
+
 class Parser:
     def __init__(self, tokens: List[Token]):
         self.tokens = tokens