Once a List is infinite, it stays infinite

Fixes: $ my @r = ^Inf; say @r.infinite; @r[^10]; say @r.infinite' True Nil
rakudo · Apr 17, 2015 · eaf99c2 · eaf99c2
1 parent 9449e15
commit eaf99c2
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/src/Perl6/Metamodel/BOOTSTRAP.nqp b/src/Perl6/Metamodel/BOOTSTRAP.nqp
@@ -2613,6 +2613,7 @@ BEGIN {
     List.HOW.add_attribute(List, scalar_attr('$!items', Mu, List));
     List.HOW.add_attribute(List, scalar_attr('$!flattens', Mu, List));
     List.HOW.add_attribute(List, scalar_attr('$!nextiter', Mu, List));
+    List.HOW.add_attribute(List, scalar_attr('$!infinite', Any, List));
     List.HOW.compose_repr(List);
 
     # class Array is List {

diff --git a/src/core/List.pm b/src/core/List.pm
@@ -39,6 +39,7 @@ my class List does Positional { # declared in BOOTSTRAP
     #   has Mu $!items;        # VM's array of our reified elements
     #   has Mu $!flattens;     # true if this list flattens its parcels
     #   has Mu $!nextiter;     # iterator for generating remaining elements
+    #   has Any $!infinite;    # is this list infinite or not
 
     method new(|) {
         my Mu $args := nqp::p6argvmarray();
@@ -150,7 +151,9 @@ my class List does Positional { # declared in BOOTSTRAP
         $count
     }
 
-    multi method infinite(List:D:) { $!nextiter.infinite }
+    multi method infinite(List:D:) {
+        $!infinite ||= ?$!nextiter.infinite;
+    }
 
     method iterator() {
         # Return a reified ListIter containing our currently reified elements