Cleaned up parser

2022-10-22 12:59:42 -07:00
parent 3cd0762d16
commit 218af2cd49
7 changed files with 170 additions and 120 deletions
@@ -1,82 +1,96 @@
 import pyparsing as pp

-# Packrat gives a MAD speed boost.
+# Packrat gives a significant speed boost.
 pp.ParserElement.enablePackrat()

-import lamb.tokens as tokens
-import lamb.utils as utils
+class LambdaParser:
+	def make_parser(self):
+		self.lp = pp.Suppress("(")
+		self.rp = pp.Suppress(")")
+		self.pp_expr = pp.Forward()

-class Parser:
-	lp = pp.Suppress("(")
-	rp = pp.Suppress(")")
+		# Bound variables are ALWAYS lowercase and single-character.
+		# We still create macro objects from them, they are turned into
+		# bound variables after the expression is built.
+		self.pp_macro = pp.Word(pp.alphas + "_")
+		self.pp_bound = pp.Char(pp.srange("[a-z]"))
+		self.pp_name = self.pp_bound ^ self.pp_macro
+		self.pp_church = pp.Word(pp.nums)

-	# Simple tokens
-	pp_expr = pp.Forward()
-	pp_macro = pp.Word(pp.alphas + "_")
-	pp_macro.set_parse_action(tokens.macro.from_parse)
+		# Function calls.
+		#
+		# <exp> <exp>
+		# <exp> <exp> <exp>
+		self.pp_call = pp.Forward()
+		self.pp_call <<= (self.pp_expr | self.pp_bound)[2, ...]

-	pp_church = pp.Word(pp.nums)
-	pp_church.set_parse_action(utils.autochurch)
+		# Function definitions, right associative.
+		# Function args MUST be lowercase.
+		#
+		# <var> => <exp>
+		self.pp_lambda_fun = (
+			(pp.Suppress("λ") | pp.Suppress("\\")) +
+			pp.Group(self.pp_bound[1, ...]) +
+			pp.Suppress(".") +
+			(self.pp_expr ^ self.pp_call)
+		)

-	# 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)
+		# Assignment.
+		# Can only be found at the start of a line.
+		#
+		# <name> = <exp>
+		self.pp_macro_def = (
+			pp.line_start() +
+			self.pp_macro +
+			pp.Suppress("=") +
+			(self.pp_expr ^ self.pp_call)
+		)

-	# Function definitions.
-	# Right associative.
-	#
-	# <var> => <exp>
-	pp_lambda_fun = (
-		(pp.Suppress("λ") | pp.Suppress("\\")) +
-		pp.Group(pp.Char(pp.alphas)[1, ...]) +
-		pp.Suppress(".") +
-		(pp_expr ^ pp_call)
-	)
-	pp_lambda_fun.set_parse_action(tokens.lambda_func.from_parse)
+		self.pp_expr <<= (
+			self.pp_church ^
+			self.pp_lambda_fun ^
+			self.pp_name ^
+			(self.lp + self.pp_expr + self.rp) ^
+			(self.lp + self.pp_call + self.rp)
+		)

-	# Assignment.
-	# Can only be found at the start of a line.
-	#
-	# <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)
-
-	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.Word(pp.alphas + "_")[0, ...]
-	pp_command.set_parse_action(tokens.command.from_parse)
+		self.pp_command = pp.Suppress(":") + pp.Word(pp.alphas + "_") + pp.Word(pp.alphas + "_")[0, ...]


-	pp_all = (
-		pp_expr ^
-		pp_macro_def ^
-		pp_command ^
-		pp_call
-	)
+		self.pp_all = (
+			self.pp_expr ^
+			self.pp_macro_def ^
+			self.pp_command ^
+			self.pp_call
+		)

-	@staticmethod
-	def parse_line(line):
-		return Parser.pp_all.parse_string(
+	def __init__(
+			self,
+			*,
+			action_command,
+			action_macro_def,
+			action_church,
+			action_func,
+			action_bound,
+			action_macro,
+			action_apply
+		):
+
+		self.make_parser()
+
+		self.pp_command.set_parse_action(action_command)
+		self.pp_macro_def.set_parse_action(action_macro_def)
+		self.pp_church.set_parse_action(action_church)
+		self.pp_lambda_fun.set_parse_action(action_func)
+		self.pp_macro.set_parse_action(action_macro)
+		self.pp_bound.set_parse_action(action_bound)
+		self.pp_call.set_parse_action(action_apply)
+
+	def parse_line(self, line: str):
+		return self.pp_all.parse_string(
 			line,
 			parse_all = True
 		)[0]

-	@staticmethod
-	def run_tests(lines):
-		return Parser.pp_all.run_tests(lines)
+	def run_tests(self, lines: list[str]):
+		return self.pp_all.run_tests(lines)