summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorspwhitton2015-12-03 02:08:58 +0000
committeradmin2015-12-03 02:08:58 +0000
commit9e2115422c7d066b8ffb4ef0a4b02c7eb758db3e (patch)
tree6bf38817c2cb2ba8de074035cd7c22628dbb60ab
parent15c69ffb3155feb355c663447e6ef1dbec2a6f2a (diff)
Added a comment
-rw-r--r--doc/todo/pull_request:_patch_Apt.buildDep_to_only_proceed_if_installable/comment_9_5694c0bec217d3513aa8e80f55482d75._comment17
1 files changed, 17 insertions, 0 deletions
diff --git a/doc/todo/pull_request:_patch_Apt.buildDep_to_only_proceed_if_installable/comment_9_5694c0bec217d3513aa8e80f55482d75._comment b/doc/todo/pull_request:_patch_Apt.buildDep_to_only_proceed_if_installable/comment_9_5694c0bec217d3513aa8e80f55482d75._comment
new file mode 100644
index 00000000..5783dd7b
--- /dev/null
+++ b/doc/todo/pull_request:_patch_Apt.buildDep_to_only_proceed_if_installable/comment_9_5694c0bec217d3513aa8e80f55482d75._comment
@@ -0,0 +1,17 @@
+[[!comment format=mdwn
+ username="spwhitton"
+ subject="comment 9"
+ date="2015-12-03T02:08:58Z"
+ content="""
+I can get what I want if I use `trivial` and `changesFile` in the way you described. So please consider adding your method as a combinator:
+
+ p `changeIfChanges` f = (trivial p) `changesFile` f
+
+which is okay because `trivial` is idempotent so `changeIfChanges` may be applied more than once (I've got this in my branch with a decent docstring and I've applied it to `Apt.buildDep`).
+
+I think that this ought to be its own combinator, rather than just a recommendation to use `trivial` and `changesFile` in such cases, because this doesn't follow the semantics of `trivial`: it's not necessarily the case that it is the same amount of work to check if the property needs to be ensured as it is to ensure it.
+
+(In this language, my `noChangeIfUnchanged` could be called `changeOnlyIfChanges`. I agree that it's very unlikely to useful.)
+
+(Again, on my machine, applying `changeIfChanges` to `Apt.buildDep` magically hides apt's output if the build-deps are already installed.)
+"""]]