Made commands more powerful, added :load and :save

README.md

@@ -2,7 +2,6 @@
 
 
 ## Todo (pre-release):
- - Good command parsing (`:save`, `:load`, are a bare minimum)
  - $\alpha$-equivalence check
  - Prettyprint functions (combine args, rename bound variables)
  - Write a nice README
@@ -18,6 +17,7 @@
  - Syntax highlighting: parenthesis, bound variables, macros, etc
  - Pin header to top of screen
  - PyPi package
+ - Smart alignment in all printouts
 
 ## Mention in Docs
  - lambda functions only work with single-letter arguments

lamb/__main__.py

@@ -8,7 +8,6 @@ from prompt_toolkit.lexers import Lexer
 
 from pyparsing import exceptions as ppx
 
-from lamb.parser import Parser
 import lamb.runner as runner
 import lamb.runstatus as rs
 import lamb.tokens as tokens
@@ -23,27 +22,29 @@ class LambdaLexer(Lexer):
 			return [("class:text", str(document.lines[line_no]))]
 		return inner
 
-# Replace "\" with a pretty "λ" in the prompt
+
+utils.show_greeting()
+
+
+# Replace "\" with pretty "λ"s
 bindings = KeyBindings()
 @bindings.add("\\")
 def _(event):
 	event.current_buffer.insert_text("λ")
 
-session = PromptSession(
-	message = FormattedText([
-		("class:prompt", "~~> ")
-	]),
+
+r = runner.Runner(
+	prompt_session = PromptSession(
 		style = utils.style,
 		lexer = LambdaLexer(),
 		key_bindings = bindings
+	),
+
+	prompt_message = FormattedText([
+		("class:prompt", "~~> ")
+	]),
 )
 
-
-utils.show_greeting()
-
-
-r = runner.Runner()
-
 r.run_lines([
 	"T = λab.a",
 	"F = λab.b",
@@ -63,7 +64,7 @@ r.run_lines([
 
 while True:
 	try:
-		i = session.prompt()
+		i = r.prompt()
 
 	# Catch Ctrl-C and Ctrl-D
 	except KeyboardInterrupt:
@@ -83,7 +84,7 @@ while True:
 	try:
 		x = r.run(i)
 	except ppx.ParseException as e:
-		l = len(to_plain_text(session.message))
+		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}."),
@@ -107,7 +108,7 @@ while True:
 
 
 	if isinstance(x, rs.CommandStatus):
-		printf(x.formatted_text, style = utils.style)
+		pass
 
 	# If this line was an expression, print reduction status
 	elif isinstance(x, rs.ReduceStatus):

lamb/commands.py

@@ -1,8 +1,12 @@
 from prompt_toolkit.formatted_text import FormattedText
 from prompt_toolkit.formatted_text import HTML
+from prompt_toolkit import print_formatted_text as printf
 from prompt_toolkit.shortcuts import clear as clear_screen
 
-from lamb.runstatus import CommandStatus
+import os.path
+
+from pyparsing import exceptions as ppx
+import lamb.runstatus as rs
 import lamb.utils as utils
 
 
@@ -16,60 +20,165 @@ def lamb_command(*, help_text: str):
 		help_texts[func.__name__] = help_text
 	return inner
 
-def run(command, runner):
+def run(command, runner) -> None:
 	if command.name not in commands:
-		return CommandStatus(
-			formatted_text = FormattedText([
+		printf(
+			FormattedText([
 				("class:warn", f"Unknown command \"{command.name}\"")
-			])
+			]),
+			style = utils.style
 		)
 	else:
-		return commands[command.name](command, runner)
+		commands[command.name](command, runner)
+
+
+@lamb_command(help_text = "Save macros to a file")
+def save(command, runner) -> None:
+	if len(command.args) != 1:
+		printf(
+			HTML(
+				"<err>Command <cmd_code>:save</cmd_code> takes exactly one argument.</err>"
+			),
+			style = utils.style
+		)
+		return
+
+	target = command.args[0]
+	if os.path.exists(target):
+		confirm = runner.prompt_session.prompt(
+			message = FormattedText([
+				("class:warn", "File exists. Overwrite? "),
+				("class:text", "[yes/no]: ")
+			])
+		).lower()
+
+		if confirm != "yes":
+			printf(
+				HTML(
+					"<err>Cancelled.</err>"
+				),
+				style = utils.style
+			)
+			return
+
+	with open(target, "w") as f:
+		f.write("\n".join(
+			[f"{n} = {e}" for n, e in runner.macro_table.items()]
+		))
+
+	printf(
+		HTML(
+			f"Wrote {len(runner.macro_table)} macros to <cmd_code>{target}</cmd_code>"
+		),
+		style = utils.style
+	)
+
+
+@lamb_command(help_text = "Load macros from a file")
+def load(command, runner):
+	if len(command.args) != 1:
+		printf(
+			HTML(
+				"<err>Command <cmd_code>:load</cmd_code> takes exactly one argument.</err>"
+			),
+			style = utils.style
+		)
+		return
+
+	target = command.args[0]
+	if not os.path.exists(target):
+		printf(
+			HTML(
+				f"<err>File {target} doesn't exist.</err>"
+			),
+			style = utils.style
+		)
+		return
+
+	with open(target, "r") as f:
+		lines = [x.strip() for x in f.readlines()]
+
+	for i in range(len(lines)):
+		l = lines[i]
+		try:
+			x = runner.run(l, macro_only = True)
+		except ppx.ParseException as e:
+			printf(
+				FormattedText([
+					("class:warn", f"Syntax error on line {i+1:02}: "),
+					("class:cmd_code", l[:e.loc]),
+					("class:err", l[e.loc]),
+					("class:cmd_code", l[e.loc+1:])
+				]),
+				style = utils.style
+			)
+		except rs.NotAMacro:
+			printf(
+				FormattedText([
+					("class:warn", f"Skipping line {i+1:02}: "),
+					("class:cmd_code", l),
+					("class:warn", f" is not a macro definition.")
+				]),
+				style = utils.style
+			)
+		else:
+			printf(
+				FormattedText([
+					("class:ok", f"Loaded {x.macro_label}: "),
+					("class:cmd_code", str(x.macro_expr))
+				]),
+				style = utils.style
+			)
+
+
 
 @lamb_command(help_text = "Delete a macro")
-def mdel(command, runner):
+def mdel(command, runner) -> None:
 	if len(command.args) != 1:
-		return CommandStatus(
-			formatted_text = HTML(
-				"<warn>Command <cmd_code>:mdel</cmd_code> takes exactly one argument.</warn>"
-			)
+		printf(
+			HTML(
+				"<err>Command <cmd_code>:mdel</cmd_code> takes exactly one argument.</err>"
+			),
+			style = utils.style
 		)
+		return
 
 	target = command.args[0]
 	if target not in runner.macro_table:
-		return CommandStatus(
-			formatted_text = HTML(
+		printf(
+			HTML(
 				f"<warn>Macro \"{target}\" is not defined</warn>"
+			),
+			style = utils.style
 		)
-		)
+		return
 
 	del runner.macro_table[target]
 
-@lamb_command(help_text = "Show macros")
-def macros(command, runner):
-	return CommandStatus(
 
-		# Can't use HTML here, certain characters might break it.
-		formatted_text = FormattedText([
+
+@lamb_command(help_text = "Show macros")
+def macros(command, runner) -> None:
+	printf(FormattedText([
 			("class:cmd_h", "\nDefined Macros:\n"),
 		] +
 		[
 			("class:cmd_text", f"\t{name} \t {exp}\n")
 			for name, exp in runner.macro_table.items()
-		]
-		)
+		]),
+		style = utils.style
 	)
 
 @lamb_command(help_text = "Clear the screen")
-def clear(command, runner):
+def clear(command, runner) -> None:
 	clear_screen()
 	utils.show_greeting()
 
 
 @lamb_command(help_text = "Print this help")
-def help(command, runner):
-	return CommandStatus(
-		formatted_text = HTML(
+def help(command, runner) -> None:
+	printf(
+		HTML(
 			"\n<cmd_text>" +
 			"<cmd_h>Usage:</cmd_h>" +
 			"\n" +
@@ -86,5 +195,6 @@ def help(command, runner):
 				for name, text in help_texts.items()
 			]) +
 			"</cmd_text>"
-		)
+		),
+		style = utils.style
 	)

lamb/runner.py

@@ -1,5 +1,4 @@
-from distutils.cmd import Command
-from prompt_toolkit.formatted_text import FormattedText
+from prompt_toolkit import PromptSession
 
 import lamb.commands as commands
 from lamb.parser import Parser
@@ -7,15 +6,19 @@ import lamb.tokens as tokens
 import lamb.runstatus as rs
 
 
-
 class Runner:
-	def __init__(self):
+	def __init__(self, prompt_session: PromptSession, prompt_message):
 		self.macro_table = {}
+		self.prompt_session = prompt_session
+		self.prompt_message = prompt_message
 
 		# Maximum amount of reductions.
 		# If None, no maximum is enforced.
 		self.reduction_limit: int | None = 300
 
+	def prompt(self):
+		return self.prompt_session.prompt(message = self.prompt_message)
+
 
 	def reduce_expression(self, expr: tokens.LambdaToken) -> rs.ReduceStatus:
 
@@ -51,7 +54,7 @@ class Runner:
 
 
 	# Apply a list of definitions
-	def run(self, line: str) -> rs.RunStatus:
+	def run(self, line: str, *, macro_only = False) -> rs.RunStatus:
 		e = Parser.parse_line(line)
 
 		# If this line is a macro definition, save the macro.
@@ -67,14 +70,20 @@ class Runner:
 				macro_expr = e.exp
 			)
 
+		elif macro_only:
+			raise rs.NotAMacro()
+
 		# If this line is a command, do the command.
 		elif isinstance(e, tokens.command):
-			return commands.run(e, self)
+			commands.run(e, self)
+			return rs.CommandStatus(cmd = e.name)
 
 		# If this line is a plain expression, reduce it.
 		elif isinstance(e, tokens.LambdaToken):
 			e.bind_variables()
 			return self.reduce_expression(e)
+
+		# We shouldn't ever get here.
 		else:
 			raise TypeError(f"I don't know what to do with a {type(e)}")
 

lamb/runstatus.py

@@ -4,6 +4,16 @@ import enum
 
 import lamb.tokens as tokens
 
+
+class NotAMacro(Exception):
+	"""
+	Raised when we try to run a non-macro line
+	while enforcing macro_only in Runner.run().
+
+	This should be caught and elegantly presented to the user.
+	"""
+	pass
+
 class RunStatus:
 	"""
 	Base class for run status.
@@ -64,14 +74,11 @@ class ReduceStatus(RunStatus):
 class CommandStatus(RunStatus):
 	"""
 	Returned when a command is executed.
+	Doesn't do anything interesting.
 
 	Values:
-	`formatted_text`: What to print after this command is executed
+	`cmd`: The command that was run, without a colon.
 	"""
 
-	def __init__(
-		self,
-		*,
-		formatted_text: FormattedText | HTML
-	):
-		self.formatted_text = formatted_text
+	def __init__(self, *, cmd: str):
+		self.cmd = cmd

lamb/utils.py

@@ -36,6 +36,7 @@ style = Style.from_dict({
 	"warn": "#FFFF00",
 	"err": "#FF0000",
 	"prompt": "#00FFFF",
+	"ok": "#B4EC85",
 
 	# Syntax
 	"syn_macro": "#FF00FF",