/* Here is a lex program, that tries to find mismatched quotes in shellscripts.
 * It assumes you are NOT trying to do sneaky things like deliberately
 * make a quoted string span multiple lines, to get the newline
 * in the string
 *
 * Yes, this is awfully similar to the way an AWK prog is structured.
 * The main difference being that AWK works on a line-by-line basis.
 * Whereas lex works on a char-by-char basis.
 * See http://www.gnu.org/manual/flex-2.5.4/html_chapter/flex_toc.html
 * for more info on lex, and the GNU version called flex.
 *
 * Name this file "quotecheck.y" 
 * Compile with "lex quotecheck.y; cc -o quotecheck lex.yy.c -ll" 
 * It looks at stdin, obviously
 */

DOUBLEQUOTE	["]
SINGLEQUOTE	[']
BACKSLASH	\\
%{
	#define YY_MAIN 1
	int dqcount=0,sqcount=0;
%}
%%
{BACKSLASH}{BACKSLASH}		ECHO;
{BACKSLASH}{DOUBLEQUOTE}	ECHO;
{BACKSLASH}{SINGLEQUOTE}	ECHO; if(sqcount==1) sqcount=0;
{DOUBLEQUOTE}	{
	ECHO;
	if(sqcount==0){
		/*printf("[toggling DQ]");*/
		dqcount=1-dqcount;
	}
}
{SINGLEQUOTE}	{
	if(dqcount==0) {
		/*printf("[toggling SQ]");*/
		sqcount=1-sqcount;
	}
	ECHO;
}
\n	{
		ECHO;
		if(sqcount>0){
			printf("***ERROR: unbalanced singlequote above.\n");
		}
		if(dqcount>0){
			printf("***ERROR: unbalanced doublequote above\n");
		}
		dqcount=0;sqcount=0;
}

.	ECHO;
%%

/* main() already defined by YY_MAIN */