Simple patch which makes bc accept _ as a valid digit character -- and
ignore them.  This is so that numbers such as 1_234_567 can be used,
which are frequently more convenient to read.

Dean

diff -ru bc-1.04.orig/bc/scan.l bc-1.04.local/bc/scan.l
--- bc-1.04.orig/bc/scan.l	Mon Apr 21 14:57:00 1997
+++ bc-1.04.local/bc/scan.l	Wed Oct  1 18:14:50 1997
@@ -135,7 +135,7 @@
 		YY_FATAL_ERROR( "read() in flex scanner failed" );
 #endif
 %}
-DIGIT [0-9A-F]
+DIGIT [0-9A-F_]
 LETTER [a-z]
 %s slcomment
 %%
@@ -255,7 +255,7 @@
 	      dst = yytext;
 	      while (*src == '0') src++;
 	      if (*src == 0) src--;
-	      /* Copy strings removing the newlines. */
+	      /* Copy strings removing the newlines and underscores. */
 	      while (*src != 0)
 		{
 	          if (*src == '\\')
@@ -263,7 +263,11 @@
 		      src++; src++;
 		      line_no++;
 		    }
-		  else
+		  else if (*src == '_')
+		    {
+		      src++;
+		    }
+		  else  
 		    *dst++ = *src++;
 	        }
 	      *dst = 0;