Need ability to reuse and expand on defined lists and mappings.

[philip@…]

Every yaml file I've created requires some form of data reuse. YAML should support list and mapping expansions using existing anchor and reference syntax.

default_items: &default
- item one
- item two
- item three
my_items: *default
- additional item

default_items: &default
  one: two
  foo: bar
my_items: *default
  one: override

Having this ability would be valuable, and appears clean and logical in terms of the existing syntax. Submitting for consideration.

[philip@…]

Sample real-world use-case

[Philip Douglass <philip@…>]

More research on my part uncovered a partial solution using the merge key described here:  http://yaml.org/type/merge.html

The second example in the original post can be validly written as:

default_items: &default
  one: two
  foo: bar
my_items:
  <<:  *default
  one: override

and the attached sample real-world use-case can also be validly written as:

database_pool:
- &default
  host:   10.10.10.1
  port:   53000
  user:   my_user
  passwd: S3kr1t
  db:     my_db
- &secondary
  <<:     *default
  host:   10.10.10.2
- <<:     *secondary
  port:   53001

However, the first example in the original post cannot be solved with the merge key, since it is only useful for mappings. Why isn't there a similar feature available for merging sequences?