Re-integrated a few features

lamb/__init__.py

@@ -0,0 +1,7 @@
+from . import utils
+from . import node
+from . import parser
+from . import commands
+
+from .runner import Runner
+from .runner import StopReason

lamb/__main__.py

@@ -1,4 +1,3 @@
-from subprocess import call
 from prompt_toolkit import PromptSession
 from prompt_toolkit.completion import WordCompleter
 from prompt_toolkit import print_formatted_text as printf
@@ -6,13 +5,9 @@ from prompt_toolkit.formatted_text import FormattedText
 from prompt_toolkit.formatted_text import to_plain_text
 from prompt_toolkit.key_binding import KeyBindings
 from prompt_toolkit.lexers import Lexer
-
 from pyparsing import exceptions as ppx
-import enum
 
-import lamb.node
-import lamb.parser
-import lamb.utils as utils
+import lamb
 
 
 # Simple lexer for highlighting.
@@ -24,7 +19,7 @@ class LambdaLexer(Lexer):
 		return inner
 
 
-utils.show_greeting()
+lamb.utils.show_greeting()
 
 
 # Replace "\" with pretty "λ"s
@@ -34,67 +29,19 @@ def _(event):
 	event.current_buffer.insert_text("λ")
 
 
-"""
-r = runner.Runner(
+r = lamb.Runner(
 	prompt_session = PromptSession(
-		style = utils.style,
+		style = lamb.utils.style,
 		lexer = LambdaLexer(),
 		key_bindings = bindings
 	),
-
 	prompt_message = FormattedText([
 		("class:prompt", "~~> ")
-	]),
-)
-"""
-
-macro_table = {}
-
-class MacroDef:
-	@staticmethod
-	def from_parse(result):
-		return MacroDef(
-			result[0].name,
-			result[1]
-		)
-
-	def __init__(self, label: str, expr: lamb.node.Node):
-		self.label = label
-		self.expr = expr
-
-	def __repr__(self):
-		return f"<{self.label} := {self.expr!r}>"
-
-	def __str__(self):
-		return f"{self.label} := {self.expr}"
-
-	def bind_variables(self):
-		return self.expr.bind_variables()
-
-class Command:
-	@staticmethod
-	def from_parse(result):
-		return Command(
-			result[0],
-			result[1:]
-		)
-
-	def __init__(self, name, args):
-		self.name = name
-		self.args = args
-
-p = lamb.parser.LambdaParser(
-	action_func = lamb.node.Func.from_parse,
-	action_bound = lamb.node.Macro.from_parse,
-	action_macro = lamb.node.Macro.from_parse,
-	action_call = lamb.node.Call.from_parse,
-	action_church = lamb.node.Church.from_parse,
-	action_macro_def = MacroDef.from_parse,
-	action_command = Command.from_parse
+	])
 )
 
 
-for l in [
+r.run_lines([
 	"T = λab.a",
 	"F = λab.b",
 	"NOT = λa.(a F T)",
@@ -110,22 +57,42 @@ for l in [
 	"MULT = λnmf.n (m f)",
 	"H = λp.((PAIR (p F)) (S (p F)))",
 	"D = λn.n H (PAIR 0 0) T",
-	"FAC = λyn.(Z n)(1)(MULT n (y (D n)))",
-	"3 NOT T"
-]:
-	n = p.parse_line(l)
-	n.bind_variables()
+	"FAC = λyn.(Z n)(1)(MULT n (y (D n)))"
+])
 
 
-	if isinstance(n, MacroDef):
-		macro_table[n.label] = n.expr
-		print(n)
-	else:
-		for i in range(100):
-			r, n = lamb.node.reduce(
-				n,
-				macro_table = macro_table
-			)
-			if not r:
-				break
-		print(n)
+while True:
+	try:
+		i = r.prompt()
+
+	# Catch Ctrl-C and Ctrl-D
+	except KeyboardInterrupt:
+		printf("\n\nGoodbye.\n")
+		break
+	except EOFError:
+		printf("\n\nGoodbye.\n")
+		break
+
+	# Skip empty lines
+	if i.strip() == "":
+		continue
+
+	# Try to run an input line.
+	# Catch parse errors and point them out.
+	try:
+		x = r.run(i)
+	except ppx.ParseException as e:
+		l = len(to_plain_text(r.prompt_session.message))
+		printf(FormattedText([
+			("class:err", " "*(e.loc + l) + "^\n"),
+			("class:err", f"Syntax error at char {e.loc}."),
+			("class:text", "\n")
+		]), style = lamb.utils.style)
+		continue
+	except lamb.node.ReductionError as e:
+		printf(FormattedText([
+			("class:err", f"{e.msg}\n")
+		]), style = lamb.utils.style)
+		continue
+
+	printf("")

lamb/commands.py

@@ -7,9 +7,7 @@ import os.path
 
 from pyparsing import exceptions as ppx
 
-import lamb.tokens
-import lamb.utils
-
+import lamb
 
 commands = {}
 help_texts = {}
@@ -114,7 +112,7 @@ def load(command, runner):
 			)
 			return
 
-		if not isinstance(x, lamb.tokens.macro_expression):
+		if not isinstance(x, lamb.runner.MacroDef):
 			printf(
 				FormattedText([
 					("class:warn", f"Skipping line {i+1:02}: "),

lamb/node.py

@@ -124,8 +124,11 @@ class Node:
 	def __str__(self) -> str:
 		return print_node(self)
 
-	def bind_variables(self):
-		return bind_variables(self)
+	def bind_variables(self, *, ban_macro_name = None):
+		return bind_variables(
+			self,
+			ban_macro_name = ban_macro_name
+		)
 
 class EndNode(Node):
 	def print_value(self):
@@ -367,7 +370,7 @@ def clone(node: Node):
 			break
 	return out
 
-def bind_variables(node: Node) -> None:
+def bind_variables(node: Node, *, ban_macro_name = None) -> None:
 
 	if not isinstance(node, Node):
 		raise TypeError(f"I don't know what to do with a {type(node)}")
@@ -375,6 +378,15 @@ def bind_variables(node: Node) -> None:
 	bound_variables = {}
 
 	for s, n in node:
+
+		# If this expression is part of a macro,
+		# make sure we don't reference it inside itself.
+		#
+		# TODO: A chain of macros could be used to work around this. Fix that!
+		if isinstance(n, Macro) and ban_macro_name is not None:
+			if n.name == ban_macro_name:
+				raise ReductionError("Macro cannot reference self")
+
 		if isinstance(n, Func):
 			if s == Direction.UP:
 				# Add this function's input to the table of bound variables.

lamb/parser.py

@@ -60,7 +60,7 @@ class LambdaParser:
 		self.pp_all = (
 			self.pp_expr ^
 			self.pp_macro_def ^
-			#self.pp_command ^
+			self.pp_command ^
 			self.pp_call
 		)
 

lamb/runner.py

@@ -1,14 +1,9 @@
-from tkinter import E
 from prompt_toolkit import PromptSession
 from prompt_toolkit.formatted_text import FormattedText
 from prompt_toolkit import print_formatted_text as printf
-
 import enum
 
-import lamb.commands as commands
-from lamb.parser import LambdaParser
-import lamb.tokens as tokens
-import lamb.utils as utils
+import lamb
 
 
 class StopReason(enum.Enum):
@@ -18,20 +13,59 @@ class StopReason(enum.Enum):
 	INTERRUPT		= ("class:warn", "User interrupt")
 	RECURSION		= ("class:err", "Python Recursion Error")
 
+class MacroDef:
+	@staticmethod
+	def from_parse(result):
+		return MacroDef(
+			result[0].name,
+			result[1]
+		)
+
+	def __init__(self, label: str, expr: lamb.node.Node):
+		self.label = label
+		self.expr = expr
+
+	def __repr__(self):
+		return f"<{self.label} := {self.expr!r}>"
+
+	def __str__(self):
+		return f"{self.label} := {self.expr}"
+
+	def bind_variables(self, *, ban_macro_name = None):
+		return self.expr.bind_variables(
+			ban_macro_name = ban_macro_name
+		)
+
+class Command:
+	@staticmethod
+	def from_parse(result):
+		return Command(
+			result[0],
+			result[1:]
+		)
+
+	def __init__(self, name, args):
+		self.name = name
+		self.args = args
+
 
 class Runner:
-	def __init__(self, prompt_session: PromptSession, prompt_message):
+	def __init__(
+		self,
+		prompt_session: PromptSession,
+		prompt_message
+	):
 		self.macro_table = {}
 		self.prompt_session = prompt_session
 		self.prompt_message = prompt_message
-		self.parser = LambdaParser(
-			action_command		= tokens.command.from_parse,
-			action_macro_def	= tokens.macro_expression.from_parse,
-			action_church		= tokens.church_num.from_parse,
-			action_func			= tokens.lambda_func.from_parse,
-			action_bound		= tokens.macro.from_parse,
-			action_macro		= tokens.macro.from_parse,
-			action_apply		= tokens.lambda_apply.from_parse
+		self.parser = lamb.parser.LambdaParser(
+			action_func = lamb.node.Func.from_parse,
+			action_bound = lamb.node.Macro.from_parse,
+			action_macro = lamb.node.Macro.from_parse,
+			action_call = lamb.node.Call.from_parse,
+			action_church = lamb.node.Church.from_parse,
+			action_macro_def = MacroDef.from_parse,
+			action_command = Command.from_parse
 		)
 
 		# Maximum amount of reductions.
@@ -49,18 +83,15 @@ class Runner:
 
 	def parse(self, line):
 		e = self.parser.parse_line(line)
-		# Give the elements of this expression access to the runner.
-		# Runner must be set BEFORE variables are bound.
-		e.set_runner(self)
-		if isinstance(e, tokens.macro_expression):
+
+		if isinstance(e, MacroDef):
 			e.bind_variables(ban_macro_name = e.label)
-		else:
+		elif isinstance(e, lamb.node.Node):
 			e.bind_variables()
 		return e
 
 
-	def reduce_expression(self, expr: tokens.LambdaToken) -> None:
-
+	def reduce(self, node: lamb.node.Node) -> None:
 		# Reduction Counter.
 		# We also count macro (and church) expansions,
 		# and subtract those from the final count.
@@ -72,36 +103,39 @@ class Runner:
 		while (self.reduction_limit is None) or (i < self.reduction_limit):
 
 			try:
-				r = expr.reduce()
+				w, r = lamb.node.reduce(
+					node,
+					macro_table = self.macro_table
+				)
 			except RecursionError:
 				stop_reason = StopReason.RECURSION
 				break
-			expr = r.output
+			node = r
 
 			#print(expr)
 			#self.prompt()
 
 			# If we can't reduce this expression anymore,
 			# it's in beta-normal form.
-			if not r.was_reduced:
+			if not w:
 				stop_reason = StopReason.BETA_NORMAL
 				break
 
 			# Count reductions
 			#i += 1
-			if (
-					r.reduction_type == tokens.ReductionType.MACRO_EXPAND or
-					r.reduction_type == tokens.ReductionType.AUTOCHURCH
-				):
-				macro_expansions += 1
-			else:
-				i += 1
+			#if (
+			#		r.reduction_type == tokens.ReductionType.MACRO_EXPAND or
+			#		r.reduction_type == tokens.ReductionType.AUTOCHURCH
+			#	):
+			#	macro_expansions += 1
+			#else:
+			i += 1
 
 		if (
 			stop_reason == StopReason.BETA_NORMAL or
 			stop_reason == StopReason.LOOP_DETECTED
 			):
-			out_str = str(r.output) # type: ignore
+			out_str = str(r) # type: ignore
 
 			printf(FormattedText([
 				("class:result_header", f"\nExit reason: "),
@@ -116,7 +150,7 @@ class Runner:
 
 				("class:result_header", "\n\n    => "),
 				("class:text", out_str),
-			]), style = utils.style)
+			]), style = lamb.utils.style)
 		else:
 			printf(FormattedText([
 				("class:result_header", f"\nExit reason: "),
@@ -127,9 +161,14 @@ class Runner:
 
 				("class:result_header", f"\nReductions: "),
 				("class:text", str(i)),
-			]), style = utils.style)
+			]), style = lamb.utils.style)
 
-	def save_macro(self, macro: tokens.macro_expression, *, silent = False) -> None:
+	def save_macro(
+			self,
+			macro: MacroDef,
+			*,
+			silent = False
+		) -> None:
 		was_rewritten = macro.label in self.macro_table
 		self.macro_table[macro.label] = macro.expr
 
@@ -139,23 +178,28 @@ class Runner:
 				("class:syn_macro", macro.label),
 				("class:text", " to "),
 				("class:text", str(macro.expr))
-			]), style = utils.style)
+			]), style = lamb.utils.style)
 
 	# Apply a list of definitions
-	def run(self, line: str, *, silent = False) -> None:
+	def run(
+			self,
+			line: str,
+			*,
+			silent = False
+		) -> None:
 		e = self.parse(line)
 
 		# If this line is a macro definition, save the macro.
-		if isinstance(e, tokens.macro_expression):
+		if isinstance(e, MacroDef):
 			self.save_macro(e, silent = silent)
 
 		# If this line is a command, do the command.
-		elif isinstance(e, tokens.command):
-			commands.run(e, self)
+		elif isinstance(e, Command):
+			lamb.commands.run(e, self)
 
 		# If this line is a plain expression, reduce it.
-		elif isinstance(e, tokens.LambdaToken):
-			self.reduce_expression(e)
+		elif isinstance(e, lamb.node.Node):
+			self.reduce(e)
 
 		# We shouldn't ever get here.
 		else: