Jira (PUP-5810) Increase performance by adding tail-call functionality to evaluator

[Henrik Lindberg (JIRA)]

Title: Message Title

Henrik Lindberg created an issue   Puppet / PUP-5810 Increase performance by adding tail-call functionality to evaluator Issue Type: Improvement Assignee: Unassigned Created: 2016/02/03 10:08 AM Priority: Normal Reporter: Henrik Lindberg There is opportunity to optimize tail calls in puppet. Now when we do not do this, we have issues with recursive functions running out of stack since each call level is expensive. We can implement this by: adding a boolean flag to the AST call instructions. in the rewrite step in the parser (where it detects parenthesized function calls), we detect if a call is a "tail-call", and we flip the "tail-call" bit in the AST when performing the call, instead of adding yet another stack level, we throw a TailCall, which contains the information needed to proceed. Tail-calls are all calls where the result of the call is also the result of the _expression_ the call is part of. If we had a return it would be wherever there is a construct like return func(). Here is an example, where some potential tail calls can be detected. function foo($x) { case $x { 1 : { tail_call() } 2: { not_tail_call(); tail_call() } } if cond { tail_call() } not_tail_call() tail_call() } Add Comment   This message was sent by Atlassian JIRA (v6.4.12#64027-sha1:e3691cc) -- You received this message because you are subscribed to the Google Groups "Puppet Bugs" group. To unsubscribe from this group and stop receiving emails from it, send an email to puppet-bugs+unsubscr...@googlegroups.com. To post to this group, send email to puppet-bugs@googlegroups.com. Visit this group at https://groups.google.com/group/puppet-bugs. For more options, visit https://groups.google.com/d/optout.