From 0af7d8b5e61692fca899c7909b530b7e0909c15e Mon Sep 17 00:00:00 2001
From: Manuel Jacob <me@manueljacob.de>
Date: Thu, 29 Jan 2026 11:34:44 +0100
Subject: [PATCH] Add lexer support for complex literals.

They are part of the current C2y ISO draft (included by N3298 [1]).

[1] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3298.htm
---
 pycparser/c_lexer.py  |  8 ++++++--
 tests/test_c_lexer.py | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/pycparser/c_lexer.py b/pycparser/c_lexer.py
index 4f66b244..b6c14d33 100644
--- a/pycparser/c_lexer.py
+++ b/pycparser/c_lexer.py
@@ -537,6 +537,7 @@ def _handle_pppragma(self) -> List[Token]:
 _bad_string_literal = '"' + _string_char + "*" + _bad_escape + _string_char + '*"'
 
 # floating constants (K&R2: A.2.5.3)
+_floating_suffix_opt = r"([FfLl][iIjJ]?|[iIjJ][FfLl]?)?"
 _exponent_part = r"""([eE][-+]?[0-9]+)"""
 _fractional_constant = r"""([0-9]*\.[0-9]+)|([0-9]+\.)"""
 _floating_constant = (
@@ -546,7 +547,9 @@ def _handle_pppragma(self) -> List[Token]:
     + _exponent_part
     + "?)|([0-9]+"
     + _exponent_part
-    + "))[FfLl]?)"
+    + "))"
+    + _floating_suffix_opt
+    + ")"
 )
 _binary_exponent_part = r"""([pP][+-]?[0-9]+)"""
 _hex_fractional_constant = (
@@ -561,7 +564,8 @@ def _handle_pppragma(self) -> List[Token]:
     + _hex_fractional_constant
     + ")"
     + _binary_exponent_part
-    + "[FfLl]?)"
+    + _floating_suffix_opt
+    + ")"
 )
 
 
diff --git a/tests/test_c_lexer.py b/tests/test_c_lexer.py
index 00acddcd..ac203301 100644
--- a/tests/test_c_lexer.py
+++ b/tests/test_c_lexer.py
@@ -128,6 +128,21 @@ def test_hexadecimal_floating_constants(self):
         self.assertTokensTypes("0x.488641p0", ["HEX_FLOAT_CONST"])
         self.assertTokensTypes("0X12.P0", ["HEX_FLOAT_CONST"])
 
+    def test_complex_constants(self):
+        self.assertTokensTypes("1.2i", ["FLOAT_CONST"])
+        self.assertTokensTypes("1.2I", ["FLOAT_CONST"])
+        self.assertTokensTypes("1.2j", ["FLOAT_CONST"])
+        self.assertTokensTypes("1.2J", ["FLOAT_CONST"])
+        self.assertTokensTypes("1.2fi", ["FLOAT_CONST"])
+        self.assertTokensTypes("1.2if", ["FLOAT_CONST"])
+
+        self.assertTokensTypes("0x1.2p3i", ["HEX_FLOAT_CONST"])
+        self.assertTokensTypes("0x1.2p3I", ["HEX_FLOAT_CONST"])
+        self.assertTokensTypes("0x1.2p3j", ["HEX_FLOAT_CONST"])
+        self.assertTokensTypes("0x1.2p3J", ["HEX_FLOAT_CONST"])
+        self.assertTokensTypes("0x1.2p3fi", ["HEX_FLOAT_CONST"])
+        self.assertTokensTypes("0x1.2p3if", ["HEX_FLOAT_CONST"])
+
     def test_char_constants(self):
         self.assertTokensTypes(r"""'x'""", ["CHAR_CONST"])
         self.assertTokensTypes(r"""L'x'""", ["WCHAR_CONST"])