From 561dcd87ffd4e4bdf76a6df6a55560cd2c1ea8fb Mon Sep 17 00:00:00 2001
From: John Doty <john@d0ty.me>
Date: Thu, 30 May 2024 19:15:20 -0700
Subject: [PATCH] Allow nonterminals to be renamed

---
 grammar.py |  4 ++--
 harness.py | 16 +++++++++++++++-
 parser.py  | 34 ++++++++++++++++++++++++++--------
 3 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/grammar.py b/grammar.py
index f59c532..b03cb36 100644
--- a/grammar.py
+++ b/grammar.py
@@ -76,7 +76,7 @@ class FineGrammar(Grammar):
             ]
         )
 
-    @rule
+    @rule("File")
     def file(self) -> Rule:
         return self._file_statement_list
 
@@ -94,7 +94,7 @@ class FineGrammar(Grammar):
     def import_statement(self) -> Rule:
         return seq(IMPORT, STRING, AS, IDENTIFIER, SEMICOLON)
 
-    @rule
+    @rule("ClassDeclaration")
     def class_declaration(self) -> Rule:
         return seq(CLASS, IDENTIFIER, self.class_body)
 
diff --git a/harness.py b/harness.py
index 1485935..2590415 100644
--- a/harness.py
+++ b/harness.py
@@ -18,6 +18,11 @@ import parser
 # from parser import Token, Grammar, rule, seq
 
 
+###############################################################################
+# Parsing Stuff
+###############################################################################
+
+
 def trace_state(stack, input, input_index, action):
     print(
         "{stack: <20}  {input: <50}  {action: <5}".format(
@@ -133,6 +138,10 @@ def parse(table: parser.ParseTable, tokens, trace=None) -> typing.Tuple[Tree | N
                 raise ValueError(f"Unknown action type: {action}")
 
 
+###############################################################################
+# Screen Stuff
+###############################################################################
+
 # https://en.wikipedia.org/wiki/ANSI_escape_code
 # https://gist.github.com/fnky/458719343aabd01cfb17a3a4f7296797
 
@@ -176,6 +185,11 @@ def leave_alt_screen():
     sys.stdout.buffer.write(CSI(b"?1049l"))
 
 
+###############################################################################
+# Dynamic Modules: Detect and Reload Modules when they Change
+###############################################################################
+
+
 class DynamicModule:
     file_name: str
     member_name: str | None
@@ -384,7 +398,7 @@ if __name__ == "__main__":
         enter_alt_screen()
 
         h = Harness(
-            start_rule="file",
+            start_rule="File",
             source_path=source_path,
         )
         h.run()
diff --git a/parser.py b/parser.py
index 12dcf67..e79a48d 100644
--- a/parser.py
+++ b/parser.py
@@ -1745,15 +1745,19 @@ def seq(*args: Rule) -> Rule:
     return result
 
 
-# @typing.overload
-# def rule(f: None | str = None) -> typing.Callable[[typing.Callable], Rule]: ...
+@typing.overload
+def rule(f: typing.Callable, /) -> Rule: ...
 
 
-# @typing.overload
-# def rule(f: typing.Callable) -> Rule: ...
+@typing.overload
+def rule(
+    name: str | None = None, transparent: bool | None = None
+) -> typing.Callable[[typing.Callable[[typing.Any], Rule]], Rule]: ...
 
 
-def rule(f: typing.Callable) -> Rule:
+def rule(
+    name: str | None | typing.Callable = None, transparent: bool | None = None
+) -> Rule | typing.Callable[[typing.Callable[[typing.Any], Rule]], Rule]:
     """The decorator that marks a method in a Grammar object as a nonterminal
     rule.
 
@@ -1761,9 +1765,23 @@ def rule(f: typing.Callable) -> Rule:
     If called with one argument, that argument is a name that overrides the name
     of the nonterminal, which defaults to the name of the function.
     """
-    name = f.__name__
-    transparent = name.startswith("_")
-    return NonTerminal(f, name, transparent)
+    if callable(name):
+        return rule()(name)
+
+    def wrapper(f: typing.Callable[[typing.Any], Rule]):
+        nonlocal name
+        nonlocal transparent
+
+        if name is None:
+            name = f.__name__
+        assert isinstance(name, str)
+
+        if transparent is None:
+            transparent = name.startswith("_")
+
+        return NonTerminal(f, name, transparent)
+
+    return wrapper
 
 
 PrecedenceList = list[typing.Tuple[Assoc, list[Rule]]]