2 files changed, 10 insertions, 0 deletions
diff --git a/src/libexpr/get-drvs.cc b/src/libexpr/get-drvs.cc
index bd0ec4781..daa987fe7 100644
--- a/src/libexpr/get-drvs.cc
+++ b/src/libexpr/get-drvs.cc
@@ -60,6 +60,15 @@ MetaInfo DrvInfo::queryMetaInfo(EvalState & state) const
 }
 
 
+string DrvInfo::queryMetaInfo(EvalState & state, const string & name) const
+{
+    /* !!! evaluates all meta attributes => inefficient */
+    MetaInfo meta = queryMetaInfo(state);
+    MetaInfo::iterator i = meta.find(name);
+    return i == meta.end() ? "" : i->second;
+}
+
+
 void DrvInfo::setMetaInfo(const MetaInfo & meta)
 {
     ATermMap metaAttrs;
diff --git a/src/libexpr/get-drvs.hh b/src/libexpr/get-drvs.hh
index 920197d1f..46dc51a56 100644
--- a/src/libexpr/get-drvs.hh
+++ b/src/libexpr/get-drvs.hh
@@ -34,6 +34,7 @@ public:
     string queryDrvPath(EvalState & state) const;
     string queryOutPath(EvalState & state) const;
     MetaInfo queryMetaInfo(EvalState & state) const;
+    string queryMetaInfo(EvalState & state, const string & name) const;
 
     void setDrvPath(const string & s)
     {