allow enabling Prism via flag or env var

Enable Prism using either --prism

    ruby --prism test.rb

or via env var

    RUBY_PRISM=1 ruby test.rb

1 files changed, 7 insertions, 0 deletions

diff --git a/vm.c b/vm.c
index 4cc19f7c23..1c91ada813 100644
--- a/vm.c
+++ b/vm.c
@@ -4192,6 +4192,13 @@ rb_ruby_verbose_ptr(void)
     return &cr->verbose;
 }
 
+bool *
+rb_ruby_prism_ptr(void)
+{
+    rb_ractor_t *cr = GET_RACTOR();
+    return &cr->prism;
+}
+
 VALUE *
 rb_ruby_debug_ptr(void)
 {