Continued assignment expression indentation

[0xc22b]

There are (at least) 2 types of continued expressions.

goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function(el,
    opt_pos) {
  var corrected = this.correctedWords_ &&
      this.correctedWords_.contains(this.activeWord_);
}

One is at the second line which is inside parentheses, in this case. We can use syntax-ppss to get the position of the opening parenthesis and back-to-indentation to get the starting point of indentation (current-column).

Another type is the line before the last one. We could not use the syntax-ppss as the starting point should be at 'var', not 'goog'.

Proposed solution

1. Make sure the line is a continued expression (js3-continued-expression-p is t)
2. Try to find the position of '='
3. Compare the position of '=' with the position of the opening parenthesis from syntax-ppss
4. If the '=' is closer, it means this is the second type, find starting point of indentation from that line.

Please see the code here. https://github.com/witterk/js3-mode/commit/05ea437419b69c0e978f32344f3c7ba1d5bdf1a2

I called a function (js3-assignment-expr-indentation) to find an indentation of a continued assignment expression twice. It would make the program slow.

I'm not sure I should check js3-continued-expression-p is true in the function as it's kind of a prerequisite.

Please feel free to advise.

[tamzinblake]

I'm not sure what problem you're trying to solve here. The general model of js3-mode is to use the AST to perform indentation. Maybe with some samples of what you're seeing and what you'd like to see instead?

[0xc22b]

What I'm seeing now is

1. goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function() {
2.   var corrected = this.correctedWords_ &&
3.     this.correctedWords_.contains(this.activeWord_);
4. }

What I'd like to see is

1. goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function() {
2.   var corrected = this.correctedWords_ &&
3.       this.correctedWords_.contains(this.activeWord_);
4. }

The difference is the indentation at line no. 3. It's an continued expression.

I set the value of js3-continued-expr-mult to be 1, js3-indent-level is 2, js3-expr-indent-offset is 2 which mean, in my understanding, the indentation of line no. 3 should be 4 spaces from the previous line (Please correct me if I'm wrong).

Now the indentation is only 2 spaces instead of 4 spaces.

[tamzinblake]

js3-expr-indent-offset is what determines the offset between var and this. js3-indent-level is only used to indent var. So when calculating where to indent this, it goes back to indentation for the previous expression (goog), adds js3-indent-level to get to where var is, and adds js3-expr-indent-offset to offset this from var.

Off the top of my head, anyway. Going to have to mess with some test cases.

[0xc22b]

Let me try again.

Here is what I'm seeing now.

1. goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function(el,
2.     opt_pos) {
3.   var corrected = this.correctedWords_ &&
4.     this.correctedWords_.contains(this.activeWord_);
5. }

What I'd like to see is

1. goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function(el,
2.   opt_pos) {
3.   var corrected = this.correctedWords_ &&
4.     this.correctedWords_.contains(this.activeWord_);
5. }

Line no. 2 and line no. 4 are continued expressions. With the setup above, they both have the same indentation which is 4 spaces.

I guessed that the indentation of line no. 2 should have 2 spaces instead.

[tamzinblake]

If you use the default settings and then set js3-boring-indentation to t, then you should get exactly what you have in the second example. Can you post your custom settings for js3-mode?

[0xc22b]

Here my custom settings.

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(js3-auto-indent-p nil)
 '(js3-auto-insert-catch-block t)
 '(js3-boring-indentation t)
 '(js3-cleanup-whitespace nil)
 '(js3-compact nil)
 '(js3-consistent-level-indent-inner-bracket t)
 '(js3-continued-expr-mult 1)
 '(js3-curly-indent-offset 0)
 '(js3-enter-indents-newline nil)
 '(js3-expr-indent-offset 2)
 '(js3-indent-on-enter-key nil)
 '(js3-lazy-commas nil)
 '(js3-lazy-dots nil)
 '(js3-lazy-operators nil)
 '(js3-paren-indent-offset 2)
 '(js3-pretty-lazy-vars nil)
 '(js3-pretty-vars nil)
 '(js3-reparse-on-indent nil)
 '(js3-square-indent-offset 0)
 '(js3-strict-missing-semi-warning t)
 '(js3-strict-var-hides-function-arg-warning t))

[tamzinblake]

Well, it's being caused primarily by js3-paren-indent-offset being set to 2. That adds 2 additional spaces to the indentation of parenthesized lists.

[0xc22b]

I've just found out that the line no. 2 in the example above is not considered to be a continued expression. I'm sorry I gave you the wrong example.

Let me give you another one.

Now here is what I'm seeing.

1. goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function(el,
2.   opt_pos) {
3.   var corrected = this.correctedWords_ &&
4.     this.correctedWords_.contains(this.activeWord_);
5.   if (corrected.substring(0, 7) !== 'http://' &&
6.       corrected.substring(0, 8) != 'https://') {
7.     corrected = 'http://' + corrected;
8.   }
9. }

What I'd like to see is

1. goog.ui.AbstractSpellChecker.prototype.showSuggestionsMenu = function(el,
2.   opt_pos) {
3.   var corrected = this.correctedWords_ &&
4.     this.correctedWords_.contains(this.activeWord_);
5.   if (corrected.substring(0, 7) !== 'http://' &&
6.     corrected.substring(0, 8) != 'https://') {
7.     corrected = 'http://' + corrected;
8.   }
9. }

The difference is the indentation at line no. 6.

In my opinion, as both line no. 4 and line no. 6 are continued expressions, they should have the same indentation.

I've set the value of js3-paren-indent-offset to be 0 but as I debugged, it's not being used in this case.

I couldn't figure it out how to set it up or it was designed to be like this. Could you help?