* `nix-instantiate --print-args': produce XML output so that the

result can be used more easily by scripts.

src/libutil/xml-writer.hh

@@ -0,0 +1,64 @@
+#ifndef __XML_WRITER_H
+#define __XML_WRITER_H
+
+#include <iostream>
+#include <string>
+#include <list>
+#include <map>
+
+using namespace std;
+
+
+typedef map<string, string> XMLAttrs;
+
+
+class XMLWriter
+{
+private:
+    
+    ostream & output;
+
+    bool closed;
+
+    list<string> pendingElems;
+
+public:
+
+    XMLWriter(ostream & output);
+    ~XMLWriter();
+
+    void close();
+
+    void openElement(const string & name,
+        const XMLAttrs & attrs = XMLAttrs());
+    void closeElement();
+
+    void writeShortElement(const string & name,
+        const XMLAttrs & attrs = XMLAttrs());
+    
+    void writeCharData(const string & data);
+
+private:
+    void writeAttrs(const XMLAttrs & attrs);
+};
+
+
+class XMLOpenElement
+{
+private:
+    XMLWriter & writer;
+public:
+    XMLOpenElement(XMLWriter & writer, const string & name,
+        const XMLAttrs & attrs = XMLAttrs())
+        : writer(writer)
+    {
+        writer.openElement(name, attrs);
+    }
+    ~XMLOpenElement()
+    {
+        writer.closeElement();
+    }
+};
+
+
+#endif /* !__XML_WRITER_H */