Fix #2033 - Allow regexp in if expression

This changeset introduces regexp in if expression with the use of the
=~ (match) and !~ (not match) operator.

Usage:

if $uname =~ /Linux|Debian/ {
  ...
}

Moreover this patch creates ephemeral variables ($0 to $9) in the current
scope which contains the regex captures:
if $uname =~ /(Linux|Debian)/ {
  notice("this is a $1 system")
}

Signed-off-by: Brice Figureau <brice-puppet@daysofwonder.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/puppet/parser/grammar.ra b/lib/puppet/parser/grammar.ra
index 68acf35aa..2040ee868 100644
--- a/lib/puppet/parser/grammar.ra
+++ b/lib/puppet/parser/grammar.ra
@@ -488,6 +488,12 @@ else:             # nothing
 # per operator :-(
 
 expression:   rvalue
+            | expression MATCH regex {
+    result = ast AST::MatchOperator, :operator => val[1][:value], :lval => val[0], :rval => val[2]
+}
+            | expression NOMATCH regex {
+    result = ast AST::MatchOperator, :operator => val[1][:value], :lval => val[0], :rval => val[2]
+}
             | expression PLUS expression {
     result = ast AST::ArithmeticOperator, :operator => val[1][:value], :lval => val[0], :rval => val[2]
 }