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authorShea Levy <shea@shealevy.com>2018-01-02T17·22-0500
committerShea Levy <shea@shealevy.com>2018-01-02T17·25-0500
commit689b2783fcae0cd0559ebd1d37ccfc3a09c4b182 (patch)
tree2f1cc6031d3756528efba21ffae570554b156431 /src
parentf68c2b5a78aa33f899ce9aa354bb1c95ed0612ce (diff)
Add hasContext primop
Diffstat (limited to 'src')
-rw-r--r--src/libexpr/primops.cc9
1 files changed, 9 insertions, 0 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index e3b5dfb420b4..6029714273a8 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -1653,6 +1653,14 @@ static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos,
 }
 
 
+static void prim_hasContext(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    PathSet context;
+    state.forceString(*args[0], context, pos);
+    mkBool(v, !context.empty());
+}
+
+
 /* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a
    builder without causing the derivation to be built (for instance,
    in the derivation that builds NARs in nix-push, when doing
@@ -2083,6 +2091,7 @@ void EvalState::createBaseEnv()
     addPrimOp("toString", 1, prim_toString);
     addPrimOp("__substring", 3, prim_substring);
     addPrimOp("__stringLength", 1, prim_stringLength);
+    addPrimOp("__hasContext", 1, prim_hasContext);
     addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext);
     addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
     addPrimOp("__hashString", 2, prim_hashString);