Added macro full-expansion

README.md

@@ -64,7 +64,7 @@ Lamb comes with a few commands. Prefix them with a `:`
 
 ## Internals
 
-Lamb treats each λ expression as a binary tree. Variable binding and reduction are all simple operations on that tree. All the magic happens inside [`nodes.py`](./lamb/nodes.py).
+Lamb treats each λ expression as a binary tree. Variable binding and reduction are all simple operations on that tree. All this magic happens in [`nodes.py`](./lamb/nodes.py).
 
 **Highlights:**
  - `TreeWalker` is the iterator we (usually) use to traverse our tree. It walks the "perimeter" of the tree, visiting some nodes multiple times.
@@ -80,16 +80,17 @@ Lamb treats each λ expression as a binary tree. Variable binding and reduction
  - Prettier colors
  - Prevent macro-chaining recursion
  - step-by-step reduction
+ - Full-reduce option (expand all macros)
  - Show a warning when a free variable is created
  - PyPi package
 
 
 ## Todo:
+ - Optimization: clone only if absolutely necessary
+ - Better class mutation: when is a node no longer valid?
+ - Loop detection
  - Command-line options (load a file, run a set of commands)
  - $\alpha$-equivalence check
  - Unchurch macro: make church numerals human-readable
- - Full-reduce option (expand all macros)
- - Print macro content if only a macro is typed
  - Smart alignment in all printouts
- - Syntax highlighting: parenthesis, bound variables, macros, etc
-
+ - Syntax highlighting: parenthesis, bound variables, macros, etc

lamb/node.py

@@ -152,6 +152,14 @@ class Node:
 		else:
 			raise TypeError("Can only set left or right side.")
 
+	def get_side(self, side: Direction):
+		if side == Direction.LEFT:
+			return self.left
+		elif side == Direction.RIGHT:
+			return self.right
+		else:
+			raise TypeError("Can only get left or right side.")
+
 
 	def go_left(self):
 		"""
@@ -210,7 +218,7 @@ class EndNode(Node):
 		raise NotImplementedError("EndNodes MUST provide a `print_value` method!")
 
 class ExpandableEndNode(EndNode):
-	def expand(self) -> tuple[ReductionType, Node]:
+	def expand(self, *, macro_table = {}) -> tuple[ReductionType, Node]:
 		raise NotImplementedError("ExpandableEndNodes MUST provide an `expand` method!")
 
 class FreeVar(EndNode):
@@ -269,7 +277,7 @@ class Church(ExpandableEndNode):
 	def print_value(self):
 		return str(self.value)
 
-	def expand(self) -> tuple[ReductionType, Node]:
+	def expand(self, *, macro_table = {}) -> tuple[ReductionType, Node]:
 		f = Bound("f")
 		a = Bound("a")
 		chain = a
@@ -518,12 +526,57 @@ def reduce(node: Node, *, macro_table = {}) -> tuple[ReductionType, Node]:
 				return ReductionType.FUNCTION_APPLY, out
 
 			elif isinstance(n.left, ExpandableEndNode):
-				if isinstance(n.left, Macro):
-					r, n.left = n.left.expand(
-						macro_table = macro_table
-					)
-				else:
-					r, n.left = n.left.expand()
+				r, n.left = n.left.expand(
+					macro_table = macro_table
+				)
 				return r, out
+	return ReductionType.NOTHING, out
 
-	return ReductionType.NOTHING, out
+
+
+# Expand all expandable end nodes.
+def force_expand_macros(node: Node, *, macro_table = {}) -> tuple[int, Node]:
+	if not isinstance(node, Node):
+		raise TypeError(f"I can't reduce a {type(node)}")
+
+
+	out = clone(node)
+	ptr = out
+	from_side = Direction.UP
+	macro_expansions = 0
+
+	while True:
+		if isinstance(ptr, ExpandableEndNode):
+			if ptr.parent is None:
+				ptr = ptr.expand(macro_table = macro_table)[1]
+				out = ptr
+				ptr._set_parent(None, None)
+			else:
+				ptr.parent.set_side(
+					ptr.parent_side, # type: ignore
+					ptr.expand(macro_table = macro_table)[1]
+				)
+				ptr = ptr.parent.get_side(
+					ptr.parent_side # type: ignore
+				)
+			macro_expansions += 1
+
+
+		if isinstance(ptr, EndNode):
+			from_side, ptr = ptr.go_up()
+		elif isinstance(ptr, Func):
+			if from_side == Direction.UP:
+				from_side, ptr = ptr.go_left()
+			elif from_side == Direction.LEFT:
+				from_side, ptr = ptr.go_up()
+		elif isinstance(ptr, Call):
+			if from_side == Direction.UP:
+				from_side, ptr = ptr.go_left()
+			elif from_side == Direction.LEFT:
+				from_side, ptr = ptr.go_right()
+			elif from_side == Direction.RIGHT:
+				from_side, ptr = ptr.go_up()
+		if ptr is node.parent:
+			break
+
+	return macro_expansions, out # type: ignore

lamb/runner.py

@@ -108,6 +108,9 @@ class Runner:
 
 		stop_reason = StopReason.MAX_EXCEEDED
 		start_time = time.time()
+		full_reduce = isinstance(node, lamb.node.ExpandableEndNode)
+		out_text = []
+
 
 		while (self.reduction_limit is None) or (i < self.reduction_limit):
 
@@ -116,7 +119,7 @@ class Runner:
 				print(f" Reducing... {i}", end = "\r")
 
 			try:
-				red_type, new_node = lamb.node.reduce(
+				red_type, node = lamb.node.reduce(
 					node,
 					macro_table = self.macro_table
 				)
@@ -124,8 +127,6 @@ class Runner:
 				stop_reason = StopReason.INTERRUPT
 				break
 
-			node = new_node
-
 			# If we can't reduce this expression anymore,
 			# it's in beta-normal form.
 			if red_type == lamb.node.ReductionType.NOTHING:
@@ -137,12 +138,20 @@ class Runner:
 			if red_type == lamb.node.ReductionType.FUNCTION_APPLY:
 				macro_expansions += 1
 
+		# Expand all macros if we need to
+		if full_reduce:
+			m, node = lamb.node.force_expand_macros(
+				node,
+				macro_table = self.macro_table
+			)
+			macro_expansions += m
+
 		if i >= self.iter_update:
 			# Clear reduction counter
 			print(" " * round(14 + math.log10(i)), end = "\r")
 
-		out_text = [
-			("class:result_header", f"\nRuntime: "),
+		out_text += [
+			("class:result_header", f"Runtime: "),
 			("class:text", f"{time.time() - start_time:.03f} seconds"),
 
 			("class:result_header", f"\nExit reason: "),
@@ -152,14 +161,19 @@ class Runner:
 			("class:text", f"{macro_expansions:,}"),
 
 			("class:result_header", f"\nReductions: "),
-			("class:text", f"{i:,}    "),
+			("class:text", f"{i:,}\t"),
 			("class:muted", f"(Limit: {self.reduction_limit:,})")
 		]
 
+		if full_reduce:
+			out_text += [
+				("class:warn", "\nAll macros have been expanded")
+			]
+
 		if (stop_reason == StopReason.BETA_NORMAL or stop_reason == StopReason.LOOP_DETECTED):
 			out_text += [
 				("class:result_header", "\n\n    => "),
-				("class:text", str(new_node)), # type: ignore
+				("class:text", str(node)), # type: ignore
 			]
 
 		printf(