Code.Fragment functions and whitespaces

[lukaszsamson]

Environment

• Elixir & Erlang/OTP versions (elixir --version): 1.13, dev

Current behavior

Code.Fragment.surround_context/2 and cursor_context/1 do not handle newlines and other whitespaces very well (e.g. when the line ends with a comment).

iex(4)> Code.Fragment.cursor_context("DateTime.utc_no")        
{:dot, {:alias, 'DateTime'}, 'utc_no'}
iex(5)> Code.Fragment.cursor_context("DateTime.\nutc_no")
{:local_or_var, 'utc_no'}
iex(5)> Code.Fragment.cursor_context("DateTime. # some comment\nutc_no")
{:local_or_var, 'utc_no'}
iex(6)> Code.Fragment.surround_context("DateTime.utc_no", {1, 11})
%{begin: {1, 1}, context: {:dot, {:alias, 'DateTime'}, 'utc_no'}, end: {1, 16}}
iex(7)> Code.Fragment.surround_context("DateTime.\nutc_no", {2, 2}) 
%{begin: {2, 1}, context: {:local_or_var, 'utc_no'}, end: {2, 7}}

Expected behavior

I don't know if this is an intended behavior to make those functions simpler but I would expect they are able to understand valid code.

[josevalim]

👍

[romul]

A funny fact: after reading the code, I've realized that code like

DateTime  .  utc_now

will be compiled quite well 😅