Lists of dictionaries are not indented correctly

[wwentland]

I'm seeing the following indentation behaviour when using yaml-mode:

foo:
  - bar: baz
    - foo: 1

I yaml-mode to indent like:

--- expected
foo:
  - bar: baz
  - foo: 1

This seems to be related to yaml-nested-sequence-re and the way it is being used in yaml-compute-indentation as either of the following changes fixes/changes this particular behaviour:

1. Change yaml-nested-sequence-re to only match lines that end with :

The following regular expression results in the "correct" behaviour in this particular case.

(defconst yaml-nested-sequence-re
  (concat "^\\(?:\\(?: *- +\\)+\\|\\(:? *-$\\)\\)"
          "\\(?:" yaml-bare-scalar-re " *:\\)?$")
  "Regexp matching a line containing one or more nested YAML sequences.")

2. Remove nested sequence check from yaml-compute-indentation

Unsurprisingly removing the yaml-nested-sequence-re check from yaml-compute-indentation to yield the following also results in the correct indentation of the snippet above.

(defun yaml-compute-indentation ()
  "Calculate the maximum sensible indentation for the current line."
  (save-excursion
    (beginning-of-line)
    (if (looking-at yaml-document-delimiter-re) 0
      (forward-line -1)
      (while (and (looking-at yaml-blank-line-re)
                  (> (point) (point-min)))
        (forward-line -1))
      (+ (current-indentation)
         (if (looking-at yaml-nested-map-re) yaml-indent-offset 0)
         (if (looking-at yaml-block-literal-re) yaml-indent-offset 0)))))

Paired with #24 it appears as if the indentation framework needs to be more context sensitive like python-mode.

[wasamasa]

Um, have you tried hitting the TAB key repeatedly? It should cycle between the following positions (with | denoting cursor):

foo:
  - bar: baz
| | |

This way you start with the right position, change to the middle, then the left one. For the record, rst-mode behaves the same. python-mode is in so far different as it uses the same indentation order, but detects special situations where it would make no sense to have the right one (like after a return line which enforces the left position). Your change eliminates the right position, only leaving the left and middle one, hence why I cannot accept your proposed suggestion. If anything, change the indentation code to cycle in a different order through the positions (like medium, right, left). Bonus points if you can detect special cases like with python-mode.

[wwentland]

@wasamasa Thanks for looking into this. I am aware that the changes outlined above are not the correct way to do this, which is I why I didn't open a PR against this repo. I simply wanted to provide a bit of context.

What would be a good approach to change the order in which the positions are being suggested?

[wasamasa]

¯\_(ツ)_/¯