Add is_punctuator_token to internal API

Replicates graphql/graphql-js@3e84962

Author: Cito

README.md

@@ -13,7 +13,7 @@ a query language for APIs created by Facebook.
 [![Code Style](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
 
 The current version 1.0.2 of GraphQL-core-next is up-to-date with GraphQL.js version
-14.2.1. All parts of the API are covered by an extensive test suite of currently 1746
+14.2.1. All parts of the API are covered by an extensive test suite of currently 1748
 unit tests.
 
 

graphql/language/lexer.py

@@ -6,7 +6,7 @@
 from .source import Source
 from .block_string import dedent_block_string_value
 
-__all__ = ["Lexer", "TokenKind", "Token"]
+__all__ = ["Lexer", "TokenKind", "Token", "is_punctuator_token"]
 
 
 class TokenKind(Enum):
@@ -103,6 +103,30 @@ def desc(self) -> str:
         return f"{kind} {value!r}" if value else kind
 
 
+_punctuator_tokens = frozenset(
+    [
+        TokenKind.BANG,
+        TokenKind.DOLLAR,
+        TokenKind.AMP,
+        TokenKind.PAREN_L,
+        TokenKind.PAREN_R,
+        TokenKind.SPREAD,
+        TokenKind.COLON,
+        TokenKind.EQUALS,
+        TokenKind.AT,
+        TokenKind.BRACKET_L,
+        TokenKind.BRACKET_R,
+        TokenKind.BRACE_L,
+        TokenKind.PIPE,
+        TokenKind.BRACE_R,
+    ]
+)
+
+
+def is_punctuator_token(token: Token) -> bool:
+    return token.kind in _punctuator_tokens
+
+
 def print_char(char):
     return repr(char) if char else TokenKind.EOF.value
 

tests/language/test_lexer.py

@@ -2,6 +2,7 @@
 
 from graphql.error import GraphQLSyntaxError
 from graphql.language import Lexer, Source, SourceLocation, Token, TokenKind
+from graphql.language.lexer import is_punctuator_token
 from graphql.pyutils import dedent, inspect
 
 
@@ -368,3 +369,29 @@ def produces_double_linked_list_of_tokens_including_comments():
             TokenKind.BRACE_R,
             TokenKind.EOF,
         ]
+
+
+def describe_is_punctuator_token():
+    def returns_true_for_punctuator_tokens():
+        assert is_punctuator_token(lex_one("!")) is True
+        assert is_punctuator_token(lex_one("$")) is True
+        assert is_punctuator_token(lex_one("&")) is True
+        assert is_punctuator_token(lex_one("(")) is True
+        assert is_punctuator_token(lex_one(")")) is True
+        assert is_punctuator_token(lex_one("...")) is True
+        assert is_punctuator_token(lex_one(":")) is True
+        assert is_punctuator_token(lex_one("=")) is True
+        assert is_punctuator_token(lex_one("@")) is True
+        assert is_punctuator_token(lex_one("[")) is True
+        assert is_punctuator_token(lex_one("]")) is True
+        assert is_punctuator_token(lex_one("{")) is True
+        assert is_punctuator_token(lex_one("|")) is True
+        assert is_punctuator_token(lex_one("}")) is True
+
+    def returns_false_for_non_punctuator_tokens():
+        assert is_punctuator_token(lex_one("")) is False
+        assert is_punctuator_token(lex_one("name")) is False
+        assert is_punctuator_token(lex_one("1")) is False
+        assert is_punctuator_token(lex_one("3.14")) is False
+        assert is_punctuator_token(lex_one('"str"')) is False
+        assert is_punctuator_token(lex_one('"""str"""')) is False