add redirect for warnings

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/api/api_parsers.cpp

@@ -242,6 +242,7 @@ extern "C" {
         std::istringstream is(s);
         ctx->set_regular_stream(ous);
         ctx->set_diagnostic_stream(ous);
+        cmd_context::scoped_redirect _redirect(*ctx);
         try {
             if (!parse_smt2_commands(*ctx.get(), is)) {
                 SET_ERROR_CODE(Z3_PARSER_ERROR, ous.str());

src/cmd_context/cmd_context.h

@@ -191,6 +191,22 @@ class cmd_context : public progress_callback, public tactic_manager, public ast_
         ~scoped_watch() { m_ctx.m_watch.stop(); }
     };
 
+    struct scoped_redirect {
+        cmd_context& m_ctx;
+        std::ostream& m_verbose;
+        std::ostream* m_warning;
+
+        scoped_redirect(cmd_context& ctx): m_ctx(ctx), m_verbose(verbose_stream()), m_warning(warning_stream()) {
+            set_warning_stream(&(*m_ctx.m_diagnostic));
+            set_verbose_stream(m_ctx.diagnostic_stream());
+        }
+
+        ~scoped_redirect() {
+            set_verbose_stream(m_verbose);
+            set_warning_stream(m_warning);
+        }
+    };
+
 
 
 protected:

src/util/warning.cpp

@@ -83,6 +83,10 @@ void set_warning_stream(std::ostream* strm) {
     g_warning_stream = strm;
 }
 
+std::ostream* warning_stream() {
+    return g_warning_stream;
+}
+
 void format2ostream(std::ostream & out, char const* msg, va_list args) {
     svector<char>  buff;
     BEGIN_ERR_HANDLER();

src/util/warning.h

@@ -28,6 +28,8 @@ void set_error_stream(std::ostream* strm);
 
 void set_warning_stream(std::ostream* strm);
 
+std::ostream* warning_stream();
+
 void warning_msg(const char * msg, ...);
 
 void format2ostream(std::ostream& out, char const* fmt, va_list args);