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[pspp] / src / language / lexer / macro.c

diff --git a/src/language/lexer/macro.c b/src/language/lexer/macro.c
index d67278c51cd4066aa3c99f973e4a0de98db4063e..584ee7f2fd3ed29e3d4880761c7176814e55c62c 100644 (file)
--- a/src/language/lexer/macro.c
+++ b/src/language/lexer/macro.c
@@ -940,6 +940,13 @@ macro_expand (const struct macro_tokens *mts,
               const struct macro_expander *me, bool *expand,
               struct macro_tokens *exp)
 {
+  /* Macro expansion:
+
+     - Macro names in macro bodies are not expanded by default.  !EVAL()
+       expands them.
+
+     - Macro names in arguments to macro invocations (outside of macro bodies)
+       are expanded by default, unless !NOEXPAND. */
   if (nesting_countdown <= 0)
     {
       printf ("maximum nesting level exceeded\n");