From de858f60d1cbe45cd24f7b65a89f79a2e86acf08 Mon Sep 17 00:00:00 2001
From: Thomas Voss <mail@thomasvoss.com>
Date: Tue, 23 Jan 2024 02:23:12 +0100
Subject: Disallow h// at the start of patterns

---
 man/grab.1 | 4 ++++
 src/grab.c | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/man/grab.1 b/man/grab.1
index 3521b9f..ab24337 100644
--- a/man/grab.1
+++ b/man/grab.1
@@ -234,6 +234,10 @@ letter,
 and highlights the capital letter(s):
 .Pp
 .Dl x/\ew+/ g/[A\-Z]/ h//
+.Pp
+The empty
+.Sq h
+operator is not permitted as the first operator in a pattern.
 .Sh ENVIRONMENT
 .Bl -tag -width GRAB_COLORS
 .It Ev GRAB_COLORS
diff --git a/src/grab.c b/src/grab.c
index 33943f0..f8f5471 100644
--- a/src/grab.c
+++ b/src/grab.c
@@ -302,6 +302,8 @@ comppat(char8_t *s)
 		if (s - p == 0) {
 			if (op.c != 'h')
 				diex("Empty regex given to ‘%c’", op.c);
+			if (ops.len == 0)
+				diex("Empty ‘h’ is not allowed as the first operator");
 			op.pat = ops.buf[ops.len - 1].pat;
 		} else
 			op.pat = mkregex(p, s - p);
-- 
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