diff --git a/embed.fnc b/embed.fnc
index 551d46880562..d759d4ccf8e1 100644
--- a/embed.fnc
+++ b/embed.fnc
@@ -3611,6 +3611,8 @@ Apxd	|void|cop_store_label \
 
 epo	|int	|keyword_plugin_standard|NN char* keyword_ptr|STRLEN keyword_len|NN OP** op_ptr
 
+epo	|int	|infix_plugin_standard|NN char* operator_ptr|STRLEN operator_len|NN struct Perl_custom_infix** def
+
 #if defined(USE_ITHREADS)
 #  if defined(PERL_IN_SV_C)
 S	|void	|unreferenced_to_tmp_stack|NN AV *const unreferenced
diff --git a/perl.h b/perl.h
index 17a21a1c420f..31a0cd118063 100644
--- a/perl.h
+++ b/perl.h
@@ -5599,10 +5599,17 @@ typedef void (*XSINIT_t) (pTHX);
 typedef void (*ATEXIT_t) (pTHX_ void*);
 typedef void (*XSUBADDR_t) (pTHX_ CV *);
 
+/* TODO: find somewhere to store this */
+struct Perl_custom_infix {
+    /* TODO: a precedence field. for now hardcoded to RELOP only */
+    OP *(*parse)(pTHX_ OP *lhs);
+};
+
 typedef OP* (*Perl_ppaddr_t)(pTHX);
 typedef OP* (*Perl_check_t) (pTHX_ OP*);
 typedef void(*Perl_ophook_t)(pTHX_ OP*);
 typedef int (*Perl_keyword_plugin_t)(pTHX_ char*, STRLEN, OP**);
+typedef int (*Perl_infix_plugin_t)(pTHX_ char*, STRLEN, struct Perl_custom_infix **);
 typedef void(*Perl_cpeep_t)(pTHX_ OP *, OP *);
 
 typedef void(*globhook_t)(pTHX);
diff --git a/perlvars.h b/perlvars.h
index c4a08e038bd1..3a899d91839f 100644
--- a/perlvars.h
+++ b/perlvars.h
@@ -245,6 +245,9 @@ PERLVAR(G, keyword_plugin_mutex, perl_mutex)   /* Mutex for PL_keyword_plugin */
 #endif
 PERLVARI(G, keyword_plugin, Perl_keyword_plugin_t, Perl_keyword_plugin_standard)
 
+/* TODO: a mutex */
+PERLVARI(G, infix_plugin, Perl_infix_plugin_t, Perl_infix_plugin_standard)
+
 PERLVARI(G, op_sequence, HV *, NULL)	/* dump.c */
 PERLVARI(G, op_seq,	UV,	0)	/* dump.c */
 
diff --git a/proto.h b/proto.h
index faca6d1366e1..1e6fc069f3f4 100644
--- a/proto.h
+++ b/proto.h
@@ -1581,6 +1581,9 @@ PERL_CALLCONV void	Perl_hv_undef_flags(pTHX_ HV *hv, U32 flags);
 
 /* PERL_CALLCONV I32	ibcmp_utf8(pTHX_ const char *s1, char **pe1, UV l1, bool u1, const char *s2, char **pe2, UV l2, bool u2); */
 #define PERL_ARGS_ASSERT_IBCMP_UTF8
+PERL_CALLCONV int	Perl_infix_plugin_standard(pTHX_ char* operator_ptr, STRLEN operator_len, struct Perl_custom_infix** def);
+#define PERL_ARGS_ASSERT_INFIX_PLUGIN_STANDARD	\
+	assert(operator_ptr); assert(def)
 PERL_CALLCONV void	Perl_init_argv_symbols(pTHX_ int argc, char **argv);
 #define PERL_ARGS_ASSERT_INIT_ARGV_SYMBOLS	\
 	assert(argv)
diff --git a/toke.c b/toke.c
index 628a79fb4320..afc3bcc6e3f5 100644
--- a/toke.c
+++ b/toke.c
@@ -12801,6 +12801,18 @@ Perl_keyword_plugin_standard(pTHX_
     return KEYWORD_PLUGIN_DECLINE;
 }
 
+int
+Perl_infix_plugin_standard(pTHX_
+        char *operator_ptr, STRLEN operator_len, struct Perl_custom_infix **def)
+{
+    PERL_ARGS_ASSERT_INFIX_PLUGIN_STANDARD;
+    PERL_UNUSED_CONTEXT;
+    PERL_UNUSED_ARG(operator_ptr);
+    PERL_UNUSED_ARG(operator_len);
+    PERL_UNUSED_ARG(def);
+    return 0;
+}
+
 /*
 =for apidoc wrap_keyword_plugin