shithub: neatroff

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eval: report divide-by-zero errors

--- a/eval.c

+++ b/eval.c

@@ -91,6 +91,13 @@

 	return 0;

 }

+static int nonzero(int n)

+{

+	if (!n)

+		errdie("neatroff: divide by zero\n");

+	return n;

+}

+

 static int evalexpr(char **s)

 {

 	int ret = evalatom(s);

@@ -100,11 +107,11 @@

 		else if (!evaljmp(s, '-'))

 			ret -= evalatom(s);

 		else if (!evaljmp(s, '/'))

-			ret /= evalatom(s);

+			ret /= nonzero(evalatom(s));

 		else if (!evaljmp(s, '*'))

 			ret *= evalatom(s);

 		else if (!evaljmp(s, '%'))

-			ret %= evalatom(s);

+			ret %= nonzero(evalatom(s));

 		else if (!evaljmp(s, '<'))

 			ret = !evaljmp(s, '=') ? ret <= evalatom(s) : ret < evalatom(s);

 		else if (!evaljmp(s, '>'))