Recognise `//=` and `||=` syntax in signature parameter defaults

These create parameters where the default expression is assigned
whenever the caller did not pass a defined (or true) value. I.e. both if
it is missing, or is present but undef (or false).

1 files changed, 26 insertions, 0 deletions

diff --git a/op.c b/op.c
index eec6da5067..8851dce046 100644
--- a/op.c
+++ b/op.c
@@ -7975,6 +7975,32 @@ S_newONCEOP(pTHX_ OP *initop, OP *padop)
 }
 
 /*
+=for apidoc newARGDEFELEMOP
+
+Constructs and returns a new C<OP_ARGDEFELEM> op which provides a defaulting
+expression given by C<expr> for the signature parameter at the index given
+by C<argindex>. The expression optree is consumed by this function and
+becomes part of the returned optree.
+
+=cut
+*/
+
+OP *
+Perl_newARGDEFELEMOP(pTHX_ I32 flags, OP *expr, I32 argindex)
+{
+    PERL_ARGS_ASSERT_NEWARGDEFELEMOP;
+
+    OP *o = (OP *)alloc_LOGOP(OP_ARGDEFELEM, expr, LINKLIST(expr));
+    o->op_flags |= (U8)(flags);
+    o->op_private = 1 | (U8)(flags >> 8);
+
+    /* re-purpose op_targ to hold @_ index */
+    o->op_targ = (PADOFFSET)(argindex);
+
+    return o;
+}
+
+/*
 =for apidoc newASSIGNOP
 
 Constructs, checks, and returns an assignment op.  C<left> and C<right>