Fixing #448 - relationships have their own syntax

You can now specify relationships directly in the language:

  File[/foo] -> Service[bar]

Specifies a normal dependency while:

  File[/foo] ~> Service[bar]

Specifies a subscription.

You can also do relationship chaining, specifying multiple
relationships on a single line:

  File[/foo] -> Package[baz] -> Service[bar]

Note that while it's confusing, you don't have to have all
of the arrows be the same direction:

  File[/foo] -> Service[bar] <~ Package[baz]

This can provide some succinctness at the cost of readability.

You can also specify full resources, rather than just
resource refs:

    file { "/foo": ensure => present } -> package { bar: ensure => installed }

But wait! There's more!  You can also specify a subscription on either side
of the relationship marker:

    yumrepo { foo: .... }
    package { bar: provider => yum, ... }
    Yumrepo <| |> -> Package <| provider == yum |>

This, finally, provides easy many to many relationships in Puppet, but it also opens
the door to massive dependency cycles.  This last feature is a very powerful stick,
and you can considerably hurt yourself with it.

Signed-off-by: Luke Kanies <luke@puppetlabs.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/puppet/parser/grammar.ra b/lib/puppet/parser/grammar.ra
index e125e327f..c505556ec 100644
--- a/lib/puppet/parser/grammar.ra
+++ b/lib/puppet/parser/grammar.ra
@@ -11,7 +11,7 @@ token QMARK LPAREN RPAREN ISEQUAL GREATEREQUAL GREATERTHAN LESSTHAN
 token IF ELSE IMPORT DEFINE ELSIF VARIABLE CLASS INHERITS NODE BOOLEAN
 token NAME SEMIC CASE DEFAULT AT LCOLLECT RCOLLECT CLASSNAME CLASSREF
 token NOT OR AND UNDEF PARROW PLUS MINUS TIMES DIV LSHIFT RSHIFT UMINUS
-token MATCH NOMATCH REGEX
+token MATCH NOMATCH REGEX IN_EDGE OUT_EDGE IN_EDGE_SUB OUT_EDGE_SUB
 
 prechigh
     right NOT
@@ -74,6 +74,18 @@ statement:    resource
             | nodedef
             | resourceoverride
             | append
+            | relationship
+
+relationship: relationship_side edge relationship_side {
+    result = AST::Relationship.new(val[0], val[2], val[1][:value], ast_context)
+}
+            | relationship edge relationship_side {
+    result = AST::Relationship.new(val[0], val[2], val[1][:value], ast_context)
+}
+
+relationship_side: resource | resourceref | collection
+
+edge: IN_EDGE | OUT_EDGE | IN_EDGE_SUB | OUT_EDGE_SUB
 
 fstatement:   NAME LPAREN funcvalues RPAREN {
     args = aryfy(val[2])