diff --git a/lex.ll b/lex.ll
index f1dcaa6f..3655220f 100644
--- a/lex.ll
+++ b/lex.ll
@@ -345,7 +345,7 @@ INT_NUMBER (([0-9]+)|(0x[0-9a-fA-F]+)|(0b[01]+))[uUlL]*[kMG]?[uUlL]*
 INT_NUMBER_DOTDOTDOT (([0-9]+)|(0x[0-9a-fA-F]+)|(0b[01]+))[uUlL]*[kMG]?[uUlL]*\.\.\.
 FLOAT_NUMBER (([0-9]+|(([0-9]+\.[0-9]*[fF]?)|(\.[0-9]+)))([eE][-+]?[0-9]+)?[fF]?)
 HEX_FLOAT_NUMBER (0x[01](\.[0-9a-fA-F]*)?p[-+]?[0-9]+[fF]?)
-FORTRAN_DOUBLE_NUMBER (([0-9]+\.[0-9]*[dD])|([0-9]+\.[0-9]*[dD][-+]?[0-9]+)|([0-9]+[dD][-+]?[0-9]+))
+FORTRAN_DOUBLE_NUMBER (([0-9]+\.[0-9]*[dD])|([0-9]+\.[0-9]*[dD][-+]?[0-9]+)|([0-9]+[dD][-+]?[0-9]+)|(\.[0-9]*[dD][-+]?[0-9]+))