From 414e5b82b8b8ce64fd3bfe003ffc2e42d1a502c6 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Fri, 21 Apr 2017 14:54:46 -0400
Subject: [PATCH] std/link: lnkCalc require expression

error if 'expr' key isn't provided.
---
 src/std/link/lnkCalc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/std/link/lnkCalc.c b/src/std/link/lnkCalc.c
index b8cab4021..ea02ad039 100644
--- a/src/std/link/lnkCalc.c
+++ b/src/std/link/lnkCalc.c
@@ -287,6 +287,10 @@ static jlif_result lnkCalc_end_map(jlink *pjlink)
 
     if (clink->pstate == ps_error)
         return jlif_stop;
+    else if (!clink->post_expr) {
+        errlogPrintf("lnkCalc: no expression ('expr' key)\n");
+        return jlif_stop;
+    }
 
     return jlif_continue;
 }