xo-reader2 xo-expression2: pprint for DDefineExpr + DVariable

xo-reader2/src/reader2/ParserStack.cpp

@@ -5,8 +5,12 @@
 
 #include "ParserStack.hpp"
 #include "SyntaxStateMachine.hpp"
+#include <xo/printable2/Printable.hpp>
+#include <xo/facet/FacetRegistry.hpp>
 
 namespace xo {
+    using xo::print::APrintable;
+    using xo::facet::FacetRegistry;
     using xo::facet::typeseq;
 
     namespace scm {
@@ -41,6 +45,48 @@ namespace xo {
             return stack->parent();
         }
 
+        void
+        ParserStack::print(std::ostream & os) const
+        {
+            os << "<ParserStack>";
+            os << xtag("ssm", "*placeholder*");
+            os << xtag("parent", "*placeholder*");
+            os << ">";
+        }
+
+        bool
+        ParserStack::pretty(const ppindentinfo & ppii) const
+        {
+            auto * pps = ppii.pps();
+
+            /* always use multiple lines */
+
+            if (ppii.upto())
+                return false;
+
+            pps->write("<ParserStack");
+
+            const ParserStack * frame = this;
+            std::size_t i_frame = 0;
+
+            while (frame) {
+                char buf[80];
+                snprintf(buf, sizeof(buf), "[%lu]", i_frame);
+
+                auto ssm = FacetRegistry::instance().variant<APrintable,
+                                                             ASyntaxStateMachine> (frame->top());
+
+                pps->newline_pretty_tag(ppii.ci1(), buf, ssm);
+
+                ++i_frame;
+                frame = frame->parent_;
+            }
+
+            pps->write(">");
+
+            return false;
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/