Create a Symbol value class

components/milkshake/BUILD

@@ -1,6 +1,7 @@
 py_project(
     name = "milkshake",
     lib_deps = [
+        py_requirement("attrs"),
         py_requirement("lark"),
     ],
 )

components/milkshake/src/python/milkshake/__init__.py

@@ -3,6 +3,7 @@
 
 from importlib.resources import files
 
+from attrs import define, field
 from lark import Lark, Tree, Token, Transformer, v_args
 
 
@@ -10,6 +11,19 @@ with files(__package__).joinpath("grammar.lark").open("r", encoding="utf-8") as
     GRAMMAR = fp.read()
 
 
+@define
+class Symbol:
+    name: str
+
+    def __eq__(self, other):
+        if isinstance(other, str):
+            return self.name == other
+        elif isinstance(other, type(self)):
+            return self.name == other.name
+        else:
+            return False
+
+
 @v_args(tree=True)
 class T(Transformer):
     """A prepackaged transformer that cleans up the quoting details."""
@@ -25,7 +39,9 @@ class T(Transformer):
     qq_map = un_qq
     qq_set = un_qq
     qq_atom = un_qq
-    qq_symbol = un_qq
+
+    def qq_symbol(self, obj):
+        return self.symbol(self.un_qq(obj))
 
     def qq_quote(self, obj):
         return self.quote(self.un_qq(obj))
@@ -37,6 +53,9 @@ class T(Transformer):
     unquote = quote
     unquote_splicing = quote
 
+    def symbol(self, obj):
+        return Symbol(obj.children[0].value)
+
 
 PARSER = Lark(GRAMMAR, start=["module", "expr"])
 

components/milkshake/src/python/milkshake/grammar.lark

@@ -56,7 +56,11 @@ string: /"([^"]|\\")+"/
 
 pattern: /\/([^\/]|\\\/)+\//
 
-number: /[+-]?(\d+r)?(\d[\d,_\.]*)([\.,][\d,_\.]*)?(e[+-]?\d+)?/
+number: US_FORMAT_NUMBER | EU_FORMAT_NUMBER | UNDERSCORE_NUMBER
+
+US_FORMAT_NUMBER: /[+-]?(\d+r)?(\d+(,\d{3})*)(\.\d+(,\d{3})*)?(e[+-]?\d+)?/
+EU_FORMAT_NUMBER: /[+-]?(\d+r)?(\d+(\.\d{3})*)(,\d+(\.\d{3})*)?(e[+-]?\d+)?/
+UNDERSCORE_NUMBER: /[+-]?(\d+r)?(\d+(_\d{3})*)([,\.]\d+(_\d{3})*)?(e[+-]?\d+)?/
 
 // Note that we're demoting Symbol from the default parse priority of 0 to -1
 // This because _anything more specific_ should be chosen over symbol

components/milkshake/test/python/test_examples.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-from milkshake import slurp
+from milkshake import slurp, Symbol
 
 from lark import Tree, Token
 import pytest
@@ -10,26 +10,26 @@ import pytest
     "input, val",
     [
         ("()", Tree("list", [])),
-        ("nil", nil := Tree("symbol", ["nil"])),
+        ("nil", nil := Symbol("nil")),
         ("(nil nil nil)", Tree("list", [nil, nil, nil])),
         (
             "(/ + - * % ^ \\ & # @ ! = |)",
             Tree(
                 "list",
                 [
-                    Tree("symbol", ["/"]),
+                    Symbol("/"),
-                    Tree("symbol", ["+"]),
+                    Symbol("+"),
-                    Tree("symbol", ["-"]),
+                    Symbol("-"),
-                    Tree("symbol", ["*"]),
+                    Symbol("*"),
-                    Tree("symbol", ["%"]),
+                    Symbol("%"),
-                    Tree("symbol", ["^"]),
+                    Symbol("^"),
-                    Tree("symbol", ["\\"]),
+                    Symbol("\\"),
-                    Tree("symbol", ["&"]),
+                    Symbol("&"),
-                    Tree("symbol", ["#"]),
+                    Symbol("#"),
-                    Tree("symbol", ["@"]),
+                    Symbol("@"),
-                    Tree("symbol", ["!"]),
+                    Symbol("!"),
-                    Tree("symbol", ["="]),
+                    Symbol("="),
-                    Tree("symbol", ["|"]),
+                    Symbol("|"),
                 ],
             ),
         ),
@@ -48,12 +48,12 @@ import pytest
             Tree(
                 "list",
                 [
-                    Tree("symbol", ["+inf"]),
+                    Symbol("+inf"),
-                    Tree("symbol", ["-inf"]),
+                    Symbol("-inf"),
-                    Tree("symbol", ["inf"]),
+                    Symbol("inf"),
-                    Tree("symbol", ["nan"]),
+                    Symbol("nan"),
-                    Tree("symbol", ["+nan"]),
+                    Symbol("+nan"),
-                    Tree("symbol", ["-nan"]),
+                    Symbol("-nan"),
                 ],
             ),
         ),
@@ -66,7 +66,7 @@ import pytest
                     Tree(
                         "list",
                         [
-                            Tree("symbol", ["nil"]),
+                            Symbol("nil"),
                             Tree(
                                 "unquote",
                                 [