nodes+parser: refactor parsing of terms and factors

Make a distinction between Summation, Subtraction, Product and Division.
Also distinguish Integers and Floats

compiler/nodes.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from beartype import beartype
+
 
 class Node:
     pass
@@ -10,7 +12,15 @@ class Operator(Node):
 
 
 class Sum(Node):
-    def __init__(self, *values: Expression):
+    def __init__(self, *values: Value):
+        self.values = values
+
+    def __repr__(self):
+        return f"{self.__class__.__name__}({', '.join(repr(v) for v in self.values)})"
+
+
+class Sub(Node):
+    def __init__(self, *values: Value):
         self.values = values
 
     def __repr__(self):
@@ -18,14 +28,35 @@ class Sum(Node):
 
 
 class Product(Node):
-    def __init__(self, *values: Expression):
+    def __init__(self, *values: Value):
         self.values = values
 
     def __repr__(self):
         return f"{self.__class__.__name__}({', '.join(repr(v) for v in self.values)})"
 
 
-class Number(Node):
+class Division(Node):
+    def __init__(self, *values: Value):
+        self.values = values
+
+    def __repr__(self):
+        return f"{self.__class__.__name__}({', '.join(repr(v) for v in self.values)})"
+
+
+BinaryOperation = Sum | Sub | Product | Division
+
+
+@beartype
+class Float(Node):
+    def __init__(self, value: float):
+        self.value = value
+
+    def __repr__(self):
+        return f"{self.__class__.__name__}({self.value})"
+
+
+@beartype
+class Integer(Node):
     def __init__(self, value: int):
         self.value = value
 
@@ -33,4 +64,13 @@ class Number(Node):
         return f"{self.__class__.__name__}({self.value})"
 
 
-Expression = Sum | Product | Number
+class Expression(Node):
+    def __init__(self, node: Node):
+        self.node = node
+
+    def __repr__(self):
+        return f"{self.__class__.__name__}({self.node})"
+
+
+Number = Float | Integer
+Value = BinaryOperation | Number

compiler/parser.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-
 from beartype.typing import List, Dict, Callable
 
 from .logger import Logger
@@ -21,6 +20,7 @@ class Parser:
     def __init__(self, tokens: List[Token]):
         self.tokens = tokens
         self.pos = 0
+        self._last_accepted_token: Tokens | None = None
 
     @property
     def token(self) -> Token:
@@ -34,11 +34,12 @@ class Parser:
 
     def next_symbol(self):
         self.pos += 1
-        logger.debug("%s", f"Advancing to token {self.pos} {self.token}")
+        logger.debug(f"Advancing to token {self.pos} {self.token}")
 
     def accept(self, *token_types: Tokens) -> False | Token:
         tok = self.token
         if self.token.kind in token_types:
+            self._last_accepted_token = self.token
             self.next_symbol()
             return tok
         return False
@@ -51,56 +52,58 @@ class Parser:
 
     def expect(self, token_type: Tokens) -> Token:
         r = self.accept(token_type)
-        logger.debug("%s", f"Expecting {token_type}, got {r}")
+        logger.debug(f"Expecting {token_type}, got {r}")
         if r is False:
             raise ParsingError(self.token.loc, f"Unexpected token '{self.token}', wanted {token_type}")
         return r
 
-    def factor(self) -> Expression:
+    def number(self, mandatory: bool = False):
+        if tok := self.accept(Tokens.Float):
+            logger.debug(f"Found float {tok}")
+            return Float(value=float(tok.value))
+        elif tok := self.accept(Tokens.Integer):
+            logger.debug(f"Found integer {tok}")
+            return Integer(value=int(tok.value))
+        elif mandatory:
+            raise ParsingError(self.token.loc, f"Unexpected token '{self.token}', wanted integer or float")
+
+    def binary_op(self, operand_func: Callable[[], Value], operators: Dict[Tokens, Value]):
+        operand = operand_func()
+
+        while operator := self.accept(*list(operators.keys())):
+            node_type = operators[operator.kind]
+            operand2 = operand_func()
+            operand = node_type(operand, operand2)
+            logger.debug(f"{node_type.__name__} of the following operands: {operand} and {operand2}")
+
+        return operand
+
+    def factor(self) -> Value:
         if self.accept(Tokens.Parens_Left):
             v = self.expression()
             self.expect(Tokens.Parens_Right)
             return v
-        elif tok := self.accept(Tokens.Number):
-            logger.debug("%s", f"Found number {self.prev_token}")
-            return Number(value=int(tok.value))
+        elif num := self.number():
+            return num
         else:
             raise ParsingError(self.token.loc, f"Unexpected token '{self.token}', wanted parenthesized expression or "
                                                f"number")
 
-    def term(self) -> Expression:
-        operations = []
-        operand = self.factor()
-        operations += [operand]
-
-        while operator := self.accept(Tokens.Op_Multiply, Tokens.Op_Divide):
-            operand = self.factor()
-            operations += [operand]
-
-        if len(operations) == 1:
-            return operations[0]
-
-        logger.debug("%s", f"Product of the following terms: {operations}")
-        return Product(*operations)
+    def term(self) -> Value:
+        return self.binary_op(self.factor, operators={
+            Tokens.Op_Multiply: Product,
+            Tokens.Op_Divide: Division,
+        })
 
     def summation(self) -> Sum:
-        operations = []
-        operand = self.term()
-        operations += [operand]
+        return self.binary_op(self.term, operators={
+            Tokens.Op_Plus: Sum,
+            Tokens.Op_Minus: Sub,
+        })
 
-        while operator := self.accept(Tokens.Op_Plus, Tokens.Op_Minus):
-            operand = self.term()
-            operations += [operand]
-
-        if len(operations) == 1:
-            return operations[0]
-
-        logger.debug("%s", f"Sum of the following terms: {operations}")
-        return Sum(*operations)
-
-    def expression(self) -> Expression:
+    def expression(self) -> Value:
         summation = self.summation()
-        return summation
+        return Expression(summation)
 
     def root(self):
         blocks = [