xo-interpreter2 stack: wrap TokenizerError as DRuntimeError

Also fix _read_eval_print() to report them!

cmake/xo_tokenizer2Config.cmake.in

@@ -6,6 +6,7 @@ include(CMakeFindDependencyMacro)
 #       must coordinate with xo_dependency() calls
 #       in src/tokenizer2/CMakeLists.txt
 #
+find_dependency(xo_stringtable2)
 find_dependency(xo_arena)
 find_dependency(indentlog)
 

include/xo/tokenizer2/TokenizerError.hpp

@@ -8,6 +8,8 @@
 #include "TkInputState.hpp"
 #include "tokentype.hpp"
 #include "span.hpp"
+#include <xo/stringtable2/String.hpp>
+#include <xo/alloc2/Allocator.hpp>
 #include <iomanip>
 
 namespace xo {
@@ -19,6 +21,7 @@ namespace xo {
          **/
         class TokenizerError {
         public:
+            using AAllocator = xo::mm::AAllocator;
             using CharT = char;
             using span_type = xo::mm::span<const CharT>;
 
@@ -89,6 +92,9 @@ namespace xo {
             /** Print human-oriented error report on @p os. **/
             void report(std::ostream & os) const;
 
+            /** Similar to report, but capture as string, allocated from @p mm **/
+            DString * report_to_string(obj<AAllocator> mm) const;
+
             ///@}
 
         private:

src/tokenizer2/CMakeLists.txt

@@ -11,6 +11,7 @@ set(SELF_SRCS
 
 xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 ${SELF_SRCS})
 # deps must coordinate with xo-tokenizer/cmake/xo_tokenizer2Config.cmake.in
+xo_dependency(${SELF_LIB} xo_stringtable2)
 xo_dependency(${SELF_LIB} xo_arena)
 xo_dependency(${SELF_LIB} indentlog)
 

src/tokenizer2/TokenizerError.cpp

@@ -54,6 +54,20 @@ namespace xo {
             }
         }
 
+        DString *
+        TokenizerError::report_to_string(obj<AAllocator> dest_mm) const
+        {
+            // FIXME:
+            // using heap here for scratch space.
+            // Would prefer to checkpoint + realloc.
+
+            std::stringstream ss;
+
+            this->report(ss);
+
+            return DString::from_str(dest_mm, ss.str());
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/