Scrunch blank lines

[John Rupley]

>From rupley!local Fri Mar 31 13:43:14 1989
In article <620 at gonzo.UUCP> daveb at gonzo.UUCP (Dave Brower) writes:
>So, I offer this week's challenge:  Smallest program that will take
>"blank line" style cpp output on stdin and send to stdout a scrunched
>version with appropriate #line directives.

The following Lex source is somewhat shorter than a previous Lex version.
Specifications assumed:  single blank lines, as well as runs of blank
lines +- <#> line directives, are to be replaced by <# lineno
"filename">; only truly blank lines (no space or tab) are to be
considered blank.  
------------------------------------------------------------------------
	char f[80];
%S P
%%
#.+\n	{sscanf(yytext,"#%d%s",&yylineno,f);BEGIN P;}
<P>.+\n	{printf("# %d %s\n",yylineno-1,f);ECHO;BEGIN 0;}
\n	BEGIN P;
.+\n	ECHO;
------------------------------------------------------------------------
John Rupley
rupley!local at megaron.arizona.edu