diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3f23fa18..ca9390cb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,6 +13,7 @@ c4_project(VERSION 0.9.0 STANDALONE
 #-------------------------------------------------------
 
 option(RYML_WITH_TAB_TOKENS "Enable parsing of tabs after ':' and '-'. This is costly and disabled by default." OFF)
+option(RYML_WITH_BACKL_BACKP "Double scalars: decode \L and \P (respectively to \u2028 and \u2029). They decode to a larger size, and require complex logic to deal with. Disabled by default." OFF)
 option(RYML_DEFAULT_CALLBACKS "Enable ryml's default implementation of callbacks: allocate(), free(), error()" ON)
 if(RYML_DEFAULT_CALLBACKS)
     option(RYML_DEFAULT_CALLBACK_USES_EXCEPTIONS "Throw exceptions instead of calling abort in the default error handler provided by ryml" OFF)
@@ -87,6 +88,10 @@ if(RYML_WITH_TAB_TOKENS)
     target_compile_definitions(ryml PUBLIC RYML_WITH_TAB_TOKENS)
 endif()
 
+if(RYML_WITH_BACKL_BACKP)
+    target_compile_definitions(ryml PUBLIC RYML_WITH_BACKL_BACKP)
+endif()
+
 if(NOT RYML_DEFAULT_CALLBACKS)
     target_compile_definitions(ryml PRIVATE RYML_NO_DEFAULT_CALLBACKS)
 else()
diff --git a/src/c4/yml/parse_engine.def.hpp b/src/c4/yml/parse_engine.def.hpp
index 1f389cc2..e8ecb29c 100644
--- a/src/c4/yml/parse_engine.def.hpp
+++ b/src/c4/yml/parse_engine.def.hpp
@@ -26,6 +26,12 @@
 #define _RYML_WITH_OR_WITHOUT_TAB_TOKENS(with, without) without
 #endif
 
+#if defined(RYML_WITH_BACKL_BACKP)
+#define _RYML_WITH_OR_WITHOUT_BACKL_BACKP(with, without) with
+#else
+#define _RYML_WITH_OR_WITHOUT_BACKL_BACKP(with, without) without
+#endif
+
 
 // scaffold:
 #define _c4dbgnextline()                           \
@@ -2753,6 +2759,10 @@ void ParseEngine<EventHandler>::_filter_dquoted_backslash(FilterProcessor &C4_RE
     }
     else if(next == 'L') // unicode line separator \u2028
     {
+        #ifndef RYML_WITH_BACKL_BACKP
+        _c4err("\\L cannot be decoded as it would expand the source buffer. "
+               "use \\u2028 instead, or #define RYML_WITH_BACKL_BACKP while compiling.");
+        #else
         // https://www.utf8-chartable.de/unicode-utf8-table.pl?start=8192&number=1024&names=-&utf8=0x&unicodeinhtml=hex
         const char payload[] = {
             _RYML_CHCONST(-0x1e, 0xe2),
@@ -2760,9 +2770,14 @@ void ParseEngine<EventHandler>::_filter_dquoted_backslash(FilterProcessor &C4_RE
             _RYML_CHCONST(-0x58, 0xa8),
         };
         proc.translate_esc_extending(payload, /*nwrite*/3, /*nread*/1);
+        #endif
     }
     else if(next == 'P') // unicode paragraph separator \u2029
     {
+        #ifndef RYML_WITH_BACKL_BACKP
+        _c4err("\\N cannot be decoded as it would expand the source buffer. "
+               "use \\u2029 instead, or #define RYML_WITH_BACKL_BACKP while compiling.");
+        #else
         // https://www.utf8-chartable.de/unicode-utf8-table.pl?start=8192&number=1024&names=-&utf8=0x&unicodeinhtml=hex
         const char payload[] = {
             _RYML_CHCONST(-0x1e, 0xe2),
@@ -2770,6 +2785,7 @@ void ParseEngine<EventHandler>::_filter_dquoted_backslash(FilterProcessor &C4_RE
             _RYML_CHCONST(-0x57, 0xa9),
         };
         proc.translate_esc_extending(payload, /*nwrite*/3, /*nread*/1);
+        #endif
     }
     else if(next == '\0')
     {