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authorShea Levy <shea@shealevy.com>2014-11-30T18·16-0500
committerShea Levy <shea@shealevy.com>2014-12-02T15·27-0500
commit320659b0cd161249c95e736c3fb309b1a73ea728 (patch)
treef58c49ae4828572d4642a4d02360f8a415a9f0f9 /src/libexpr/primops.cc
parent5f04da905fcd01ea2d68cdbf7af41c836df5bb4e (diff)
Allow external code using libnixexpr to add types
Code that links to libnixexpr (e.g. plugins loaded with importNative, or
nix-exec) may want to provide custom value types and operations on
values of those types. For example, nix-exec is currently using sets
where a custom IO value type would be more appropriate. This commit
provides a generic hook for such types in the form of tExternal and the
ExternalBase virtual class, which contains all functions necessary for
libnixexpr's type-polymorphic functions (e.g. `showType`) to be
implemented.
Diffstat (limited to 'src/libexpr/primops.cc')
-rw-r--r--src/libexpr/primops.cc3
1 files changed, 3 insertions, 0 deletions
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index b0596dad9470..e7b79604699b 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -187,6 +187,9 @@ static void prim_typeOf(EvalState & state, const Pos & pos, Value * * args, Valu
         case tPrimOpApp:
             t = "lambda";
             break;
+	case tExternal:
+            t = args[0]->external->typeOf();
+            break;
         default: abort();
     }
     mkString(v, state.symbols.create(t));