summaryrefslogtreecommitdiff
path: root/doc/forum/property_combinator_ordering/comment_1_0ea2186b5cfa7eadaf38ac2e97fc4a2c._comment
diff options
context:
space:
mode:
Diffstat (limited to 'doc/forum/property_combinator_ordering/comment_1_0ea2186b5cfa7eadaf38ac2e97fc4a2c._comment')
-rw-r--r--doc/forum/property_combinator_ordering/comment_1_0ea2186b5cfa7eadaf38ac2e97fc4a2c._comment31
1 files changed, 31 insertions, 0 deletions
diff --git a/doc/forum/property_combinator_ordering/comment_1_0ea2186b5cfa7eadaf38ac2e97fc4a2c._comment b/doc/forum/property_combinator_ordering/comment_1_0ea2186b5cfa7eadaf38ac2e97fc4a2c._comment
new file mode 100644
index 00000000..c41abd90
--- /dev/null
+++ b/doc/forum/property_combinator_ordering/comment_1_0ea2186b5cfa7eadaf38ac2e97fc4a2c._comment
@@ -0,0 +1,31 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 1"""
+ date="2014-12-01T15:53:11Z"
+ content="""
+I think that should behave intuitively, but of course if you're unsure
+of this kind of thing, adding parens is a good way to disambiguate the
+code.
+
+ (f `File.hasContent` cfg `onChange` update)
+ `requires` File.dirExists confDir
+
+Written that way, it's explicit that the parenthesized part runs
+together as one action.
+
+Or, we can do a quick test in ghci:
+
+ joey@darkstar:~/src/propellor/src#joeyconfig>ghci Propellor.hs Propellor/Property.hs
+ *Propellor> let f1 = property "hasContent" (liftIO (print "f1") >> return MadeChange)
+ *Propellor> let f2 = property "update" (liftIO (print "f2") >> return MadeChange)
+ *Propellor> let f3 = property "dirExists" (liftIO (print "f3") >> return MadeChange)
+ *Propellor> runPropellor (Host "foo" [] mempty) $ ensureProperty $ f1 `onChange` f2 `requires` f3
+ "dirExists"
+ "hasContent"
+ "update"
+ MadeChange
+
+So, yes, it's behaving as it should, first ensuring that the `requires`
+property is met, and then running the main property, and since it made a
+change, following up by running the `onChange` property.
+"""]]