diff --git a/DHParser/server.py b/DHParser/server.py
index cd98cdc6f1085140128f910c8986fd3d545066de..9024a884f83fbc4498899ce69b2257db348a7aa6 100644
--- a/DHParser/server.py
+++ b/DHParser/server.py
@@ -77,7 +77,7 @@ JSON_Type = Union[Dict, Sequence, str, int, None]
 
 RE_IS_JSONRPC = b'\s*{'  # b'\s*(?:{|\[|"|\d|true|false|null)'
 RE_GREP_URL = b'GET ([^ \n]+) HTTP'
-RE_FUNCTION_CALL = b'\s*(\w+)\(([^)\n]*)\)'
+RE_FUNCTION_CALL = b'\s*(\w+)\(([^)]*)\)$'
 
 SERVER_ERROR = "COMPILER-SERVER-ERROR"
 
diff --git a/DHParser/toolkit.py b/DHParser/toolkit.py
index 9e94e20f11048718a96cbc63c5f83f30f6c4b1ca..4e37c82ab540c1fb4d2c7d59afe94258fb63d322 100644
--- a/DHParser/toolkit.py
+++ b/DHParser/toolkit.py
@@ -249,6 +249,8 @@ def isgenerictype(t):
 #
 #######################################################################
 
+RX_FILEPATH = re.compile(r'[^ \t][^\n\t?*]+(?<![ \t])')  # r'[\w/:. \\]+'
+
 
 def load_if_file(text_or_file) -> str:
     """
@@ -264,7 +266,7 @@ def load_if_file(text_or_file) -> str:
                 content = f.read()
             return content
         except FileNotFoundError:
-            if re.fullmatch(r'[\w/:. \\]+', text_or_file):
+            if RX_FILEPATH.fullmatch(text_or_file):
                 raise FileNotFoundError('Not a valid file: ' + text_or_file + '!\n(Add "\\n" '
                                         'to distinguish source data from a file name.)')
             else:
diff --git a/test/test_ebnf.py b/test/test_ebnf.py
index 0badea6a22e5667d48fe81094182402ad834e8cb..b24eb3d715b82b247c54fb7e870d8fed8e14522a 100644
--- a/test/test_ebnf.py
+++ b/test/test_ebnf.py
@@ -185,7 +185,7 @@ class TestParserNameOverwriteBug:
         assert not has_errors(messages), str(messages)
 
     def test_single_mandatory_bug(self):
-        lang = """series = § /B/"""
+        lang = """series = § /B/\n"""
         result, messages, ast = compile_ebnf(lang)
         assert result.find('Required') < 0
         parser = grammar_provider(lang)()
@@ -415,8 +415,8 @@ class TestFlowControlOperators:
         """Tests whether failures to comply with the required operator '§'
         are correctly reported as such.
         """
-        lang1 = r"nonsense == /\w+/~  # wrong_equal_sign"
-        lang2 = "nonsense = [^{}%]+  # someone forgot the '/'-delimiters for regular expressions"
+        lang1 = r"nonsense == /\w+/~  # wrong_equal_sign "
+        lang2 = "nonsense = [^{}%]+  # someone forgot the '/'-delimiters for regular expressions\n"
         try:
             parser_class = grammar_provider(lang1)
             assert False, "Compilation error expected."
diff --git a/test/test_parse.py b/test/test_parse.py
index 1f803b54fc4faa61efffbfe9ce80f07e1297f535..ba17ad98f58a8c2f4fc7296ad31bdca51a6af301 100644
--- a/test/test_parse.py
+++ b/test/test_parse.py
@@ -662,7 +662,7 @@ class TestErrorReporting:
 
 class TestBorderlineCases:
     def test_not_matching(self):
-        minilang = """parser = /X/"""
+        minilang = """parser = /X/\n"""
         gr = grammar_provider(minilang)()
         cst = gr('X', 'parser')
         assert not cst.error_flag
diff --git a/test/test_toolkit.py b/test/test_toolkit.py
index 15d6e029f33e8ce11ec52039ead24da680d32908..c639d07231a329b1740668d0646e131a10033be0 100644
--- a/test/test_toolkit.py
+++ b/test/test_toolkit.py
@@ -38,7 +38,7 @@ class TestLoggingAndLoading:
         self.filename = os.path.join("test", self.tmpname, "test.py") if os.path.isdir('test') \
             else os.path.join(self.tmpname, "test.py")
         self.dirname = os.path.dirname(self.filename)
-        self.code1 = "x = 46"
+        self.code1 = "x = 46\n"
         self.code2 = "def f():\n    return 46"
         if not os.path.exists(self.dirname):
             os.mkdir(self.dirname)