Improve auto-indentation behaviour

[balta2ar]

Environment data

VS Code version: Version 1.19.0
Commit 816be6780ca8bd0ab80314e11478c48c70d09383
Date 2017-12-14T09:56:48.842Z
Shell 1.7.9
Renderer 58.0.3029.110
Node 7.9.0
Architecture x64

Python Extension version: 0.9.1
Python Version: Python 3.6.3
OS and version: ArchLinux

Case 1

The cursor is at | position (about to add second argument to print), and I press Enter:

Actual

def case1():
    print('first_argument', |)

It becomes:

def case1():
    print('first_argument', 
    |)

Expected 1

def case1():
    print('first_argument'
        |)

OR Expected 2 (this one is preferred)

def case1():
    print('first_argument'
          |)

Case 2

Actual

The cursor is right after the closing parenthesis and I press Enter.

def case2():
    print(
        'some_very_very_very_very_long_function_argument_',
        'second_argument')|

It becomes:

def case2():
    print(
        'some_very_very_very_very_long_function_argument_',
        'second_argument')
        |

Expected

def case2():
    print(
        'some_very_very_very_very_long_function_argument_',
        'second_argument')
    |

Case 3

Actual

The cursor after the comment. Press Enter:

def case3(): # some comment|

It becomes:

def case3(): # some comment
|

Expected

def case3(): # some comment
    |

Same with comments after for loops:

def case3(): # some comment
    for i in range(1): # another comment|

after pressing Enter becomes

def case3(): # some comment
    for i in range(1): # another comment
    |

Expected:

def case3(): # some comment
    for i in range(1): # another comment
        |

Also look at #3284

[balta2ar]

Added case 3.

[balta2ar]

Case 3 actually has been reported in #385.

[MikhailArkhipov]

Case 3 is fixed by #385
Case 1 is a matter of taste. TypeScript or C# don't auto-indent to arguments. Also, some people prefer their own continuation rules - by opening brace, by first letter, by comma as in this style

print(a
       , b

Case 2 requires AST analysis and extension currently has no facilities for this.

[DonJayamanne]

Case 1 is a matter of taste

Agreed. Guess this is why VS has options to configure how these things get formatted.

[balta2ar]

Case 1 is a matter of taste. TypeScript or C# don't auto-indent to arguments

Really? That's surprising to me. I'm so used to such indentation in vim and I find it very natural to have. Think about it: you're inside parenthesis, typing function arguments. Why would you not want to have an indentation, at least any of the two? It's a continuation of a function call and we always indent them, aren't we?

Guess this is why VS has options to configure how these things get formatted

Could you please direct me to such configuration? I looked through the VSCode settings filtering them by "indent" and "format" and only found this relevant option: "editor.autoIndent": true,.

Case 2 requires AST analysis and extension currently has no facilities for this.

Are there any plans to add such facilities? Maybe this case could be moved out into a separate issue so that you could keep it on your backlog if it's not possible to implement it with the current facilities?

[DonJayamanne]

Could you please direct me to such configuration?

May be i was wrong, I just assumed this was one of the settings. Could be something in Reshparer. Either way I could be mistaken.

[MikhailArkhipov]

@balta2ar - it depends on the language and I meant big VS IDE. C# simple preserves user indentation of arguments. By default it indents one level deeper and not by ( or first argument

In R there is setting

Yes, there are plans to have AST analysis, but this is pretty big work item. Working on it :-)

[balta2ar]

Yes, there are plans to have AST analysis, but this is pretty big work item. Working on it :-)

That's great! Thanks for giving a heads up! Oh, and speaking of AST. There is no doubt you know how to do it right, but I noticed this comment today: atom/atom#13877 (comment)
There is this thing https://github.com/tree-sitter/tree-sitter:

Tree-sitter is a C library for incremental parsing, intended to be used via bindings to higher-level languages. It can be used to build a concrete syntax tree for a program and efficiently update the syntax tree as the program is edited. This makes it suitable for use in text-editing programs

I haven't tried it in practice myself yet, but it sounds promising from the description. Just spreading the word :-)