Fixed parser, added macro printout

.vscode/settings.json

@@ -1,7 +1,9 @@
 {
     "cSpell.words": [
+        "autochurch",
         "freevar",
         "pyparsing",
+        "runstatus",
         "subvar"
     ],
     "python.analysis.typeCheckingMode": "basic"

README.md

@@ -2,15 +2,12 @@
 
 
 ## Todo (pre-release):
- - Fix parser (call parentheses)
  - Good command parsing (`:save`, `:load`, are a bare minimum)
  - Python files: installable, package list, etc
  - $\alpha$-equivalence check
  - Versioning
- - Automatic church numerals
  - Prettyprint functions (combine args, rename bound variables)
  - Documentation in README
- - Don't crash on errors
 
 ## Todo:
  - live syntax check
@@ -20,6 +17,8 @@
  - Warn when overwriting macro
  - Syntax highlighting: parenthesis, bound variables, macros, etc
  - Pin header to top of screen
+ - Parser is a bit slow. Maybe we can do better?
 
 ## Mention in Docs
- - lambda functions only work with single-letter arguments
+ - lambda functions only work with single-letter arguments
+ - church numerals

main.py

@@ -43,7 +43,7 @@ r.run_lines([
 	"OR = λab.(a T b)",
 	"XOR = λab.(a (NOT a b) b)",
 	"w = λx.(x x)",
-	"W = (w w)",
+	"W = w w",
 	"Y = λf.( (λx.(f (x x))) (λx.(f (x x))) )",
 	"PAIR = λabi.( i a b )",
 	"inc = λnfa.(f (n f a))",
@@ -90,7 +90,13 @@ while True:
 
 	# If this line defined a macro, print nothing.
 	if isinstance(x, runner.MacroStatus):
-		pass
+		printf(FormattedText([
+			("#FFFFFF", "Set "),
+			("#FF00FF", x.macro_label),
+			("#FFFFFF", " to "),
+			("#FFFFFF", str(x.macro_expr))
+		]))
+
 
 	if isinstance(x, runner.CommandStatus):
 		printf(x.formatted_text)

parser.py

@@ -1,17 +1,8 @@
 import pyparsing as pp
 import tokens
+import utils
 
 class Parser:
-	"""
-	Macro_def must be on its own line.
-	macro_def  :: var = expr
-
-	var        :: word
-	lambda_fun :: var -> expr
-	call       :: '(' (var | expr) ')' +
-	expr       :: define | var | call | '(' expr ')'
-	"""
-
 	lp = pp.Suppress("(")
 	rp = pp.Suppress(")")
 
@@ -20,6 +11,18 @@ class Parser:
 	pp_macro = pp.Word(pp.alphas + "_")
 	pp_macro.set_parse_action(tokens.macro.from_parse)
 
+	pp_church = pp.Word(pp.nums)
+	pp_church.set_parse_action(utils.autochurch)
+
+	# Function calls.
+	# `tokens.lambda_apply.from_parse` handles chained calls.
+	#
+	# <exp> <exp>
+	# <exp> <exp> <exp>
+	pp_call = pp.Forward()
+	pp_call <<= pp_expr[2, ...]
+	pp_call.set_parse_action(tokens.lambda_apply.from_parse)
+
 	# Function definitions.
 	# Right associative.
 	#
@@ -28,41 +31,44 @@ class Parser:
 		(pp.Suppress("λ") | pp.Suppress("\\")) +
 		pp.Group(pp.Char(pp.alphas)[1, ...]) +
 		pp.Suppress(".") +
-		pp_expr
+		(pp_expr ^ pp_call)
 	)
 	pp_lambda_fun.set_parse_action(tokens.lambda_func.from_parse)
 
 	# Assignment.
 	# Can only be found at the start of a line.
 	#
-	# <var> = <exp>
-	pp_macro_def = pp.line_start() + pp_macro + pp.Suppress("=") + pp_expr
+	# <name> = <exp>
+	pp_macro_def = (
+		pp.line_start() +
+		pp_macro +
+		pp.Suppress("=") +
+		(pp_expr ^ pp_call)
+	)
 	pp_macro_def.set_parse_action(tokens.macro_expression.from_parse)
 
-	# Function calls.
-	# `tokens.lambda_func.from_parse` handles chained calls.
-	#
-	# <var>(<exp>)
-	# <var>(<exp>)(<exp>)(<exp>)
-	# (<exp>)(<exp>)
-	# (<exp>)(<exp>)(<exp>)(<exp>)
-	pp_call = pp.Forward()
-	pp_call <<= pp_expr[2, ...]
-	pp_call.set_parse_action(tokens.lambda_apply.from_parse)
-
-	pp_expr <<= pp_lambda_fun ^ (lp + pp_expr + rp) ^ pp_macro ^ (lp + pp_call + rp)
-	pp_all = pp_expr | pp_macro_def
+	pp_expr <<= (
+		pp_church ^
+		pp_lambda_fun ^
+		pp_macro ^
+		(lp + pp_expr + rp) ^
+		(lp + pp_call + rp)
+	)
 
 	pp_command = pp.Suppress(":") + pp.Word(pp.alphas + "_")
 	pp_command.set_parse_action(tokens.command.from_parse)
 
+
+	pp_all = (
+		pp_expr ^
+		pp_macro_def ^
+		pp_command ^
+		pp_call
+	)
+
 	@staticmethod
 	def parse_line(line):
-		k = (
-			Parser.pp_expr ^
-			Parser.pp_macro_def ^
-			Parser.pp_command ^ Parser.pp_call
-		).parse_string(
+		k = Parser.pp_all.parse_string(
 			line,
 			parse_all = True
 		)[0]
@@ -71,4 +77,4 @@ class Parser:
 
 	@staticmethod
 	def run_tests(lines):
-		return Parser.pp_macro_def.run_tests(lines)
+		return Parser.pp_all.run_tests(lines)

runner.py

@@ -10,10 +10,6 @@ from runstatus import ReduceStatus
 from runstatus import CommandStatus
 
 
-
-
-
-
 class Runner:
 	def __init__(self):
 		self.macro_table = {}
@@ -43,7 +39,7 @@ class Runner:
 		i = 0
 		macro_expansions = 0
 
-		while i < self.reduction_limit:
+		while (self.reduction_limit is None) or (i < self.reduction_limit):
 			r = expr.reduce(self.macro_table)
 			expr = r.output
 
@@ -64,7 +60,7 @@ class Runner:
 		return ReduceStatus(
 			reduction_count = i - macro_expansions,
 			stop_reason = StopReason.MAX_EXCEEDED,
-			result = r.output
+			result = r.output  # type: ignore
 		)
 
 
@@ -81,7 +77,8 @@ class Runner:
 
 			return MacroStatus(
 				was_rewritten = was_rewritten,
-				macro_label = e.label
+				macro_label = e.label,
+				macro_expr = e.exp
 			)
 
 		# If this line is a command, do the command.
@@ -89,9 +86,11 @@ class Runner:
 			return self.exec_command(e.name)
 
 		# If this line is a plain expression, reduce it.
-		else:
+		elif isinstance(e, tokens.LambdaToken):
 			e.bind_variables()
 			return self.reduce_expression(e)
+		else:
+			raise TypeError(f"I don't know what to do with a {type(e)}")
 
 
 	def run_lines(self, lines: list[str]):

runstatus.py

@@ -17,16 +17,19 @@ class MacroStatus(RunStatus):
 	Values:
 	`was_rewritten`:	If true, an old macro was replaced.
 	`macro_label`:		The name of the macro we just made.
+	`macro_expr`:		The expr of the macro we just made.
 	"""
 
 	def __init__(
 		self,
 		*,
 		was_rewritten: bool,
-		macro_label: str
+		macro_label: str,
+		macro_expr
 	):
 		self.was_rewritten = was_rewritten
 		self.macro_label = macro_label
+		self.macro_expr = macro_expr
 
 
 class StopReason(enum.Enum):

tokens.py

@@ -302,9 +302,9 @@ class lambda_func(LambdaToken):
 
 
 		# Bind variables inside this function.
-		if isinstance(self.output, macro):
+		if isinstance(self.output, macro) and placeholder is not None:
 			if self.output == placeholder:
-				self.output = val
+				self.output = val # type: ignore
 		elif isinstance(self.output, lambda_func):
 			self.output.bind_variables(placeholder, val)
 		elif isinstance(self.output, lambda_apply):
@@ -345,7 +345,7 @@ class lambda_func(LambdaToken):
 		calling_self = False
 		if bound_var is None:
 			calling_self = True
-			bound_var = self.input
+			bound_var = self.input # type: ignore
 		new_out = self.output
 		if isinstance(self.output, bound_variable):
 			if self.output == bound_var:
@@ -353,7 +353,7 @@ class lambda_func(LambdaToken):
 		elif isinstance(self.output, lambda_func):
 			new_out = self.output.apply(val, bound_var = bound_var)
 		elif isinstance(self.output, lambda_apply):
-			new_out = self.output.sub_bound_var(val, bound_var = bound_var)
+			new_out = self.output.sub_bound_var(val, bound_var = bound_var) # type: ignore
 
 		# If we're applying THIS function,
 		# just give the output
@@ -430,7 +430,7 @@ class lambda_apply(LambdaToken):
 		# everything below should still work as expected.
 		if isinstance(self.fn, macro) and placeholder is not None:
 			if self.fn == placeholder:
-				self.fn = val
+				self.fn = val # type: ignore
 		elif isinstance(self.fn, lambda_func):
 			self.fn.bind_variables(placeholder, val)
 		elif isinstance(self.fn, lambda_apply):
@@ -438,7 +438,7 @@ class lambda_apply(LambdaToken):
 
 		if isinstance(self.arg, macro) and placeholder is not None:
 			if self.arg == placeholder:
-				self.arg = val
+				self.arg = val # type: ignore
 		elif isinstance(self.arg, lambda_func):
 			self.arg.bind_variables(placeholder, val)
 		elif isinstance(self.arg, lambda_apply):

utils.py

@@ -0,0 +1,24 @@
+import tokens
+
+def autochurch(results):
+	"""
+	Makes a church numeral from an integer.
+	"""
+
+	num = int(results[0])
+
+	f = tokens.bound_variable()
+	a = tokens.bound_variable()
+
+	chain = a
+
+	for i in range(num):
+		chain = tokens.lambda_apply(f, chain)
+
+	return tokens.lambda_func(
+		f,
+		tokens.lambda_func(
+			a,
+			chain
+		)
+	)