* Refactoring: move derivation evaluation to libexpr.

src/libexpr/get-drvs.cc

@@ -0,0 +1,67 @@
+#include "get-drvs.hh"
+#include "nixexpr-ast.hh"
+
+
+bool getDerivation(EvalState & state, Expr e, DrvInfo & drv)
+{
+    ATermList es;
+    e = evalExpr(state, e);
+    if (!matchAttrs(e, es)) return false;
+
+    ATermMap attrs;
+    queryAllAttrs(e, attrs, false);
+    
+    Expr a = attrs.get("type");
+    if (!a || evalString(state, a) != "derivation") return false;
+
+    a = attrs.get("name");
+    if (!a) throw badTerm("derivation name missing", e);
+    drv.name = evalString(state, a);
+
+    a = attrs.get("system");
+    if (!a)
+        drv.system = "unknown";
+    else
+        drv.system = evalString(state, a);
+
+    drv.attrs = attrs;
+
+    return true;
+}
+
+
+void getDerivations(EvalState & state, Expr e, DrvInfos & drvs)
+{
+    ATermList es;
+    DrvInfo drv;
+
+    e = evalExpr(state, e);
+
+    if (getDerivation(state, e, drv)) 
+        drvs.push_back(drv);
+
+    else if (matchAttrs(e, es)) {
+        ATermMap drvMap;
+        queryAllAttrs(e, drvMap);
+        for (ATermIterator i(drvMap.keys()); i; ++i) {
+            debug(format("evaluating attribute `%1%'") % aterm2String(*i));
+            if (getDerivation(state, drvMap.get(*i), drv))
+                drvs.push_back(drv);
+            else
+                ;
+                //                parseDerivations(state, drvMap.get(*i), drvs);
+        }
+    }
+
+    else if (matchList(e, es)) {
+        for (ATermIterator i(es); i; ++i) {
+            debug(format("evaluating list element"));
+            if (getDerivation(state, *i, drv))
+                drvs.push_back(drv);
+            else
+                getDerivations(state, *i, drvs);
+        }
+    }
+}
+
+