connect: expanded formatting modes

[GRISHNOV]

The patch introduces formatting modes for the interactive console [1].

Closes #162

@TarantoolBot document
Title: Expanded formatting modes

The patchset introduces addition commands for the tt connect console.

It adds several common commands that relate to a general functionality:

• \help, ? - to show help message with additional information and a list of all commands.
• \quit, \q - quit from the console. Previously this command worked on the tarantool side, but now it works on the tt side and does not require execution rights for a user.

In addition, the patch adds commands for extended output modes:

• \set output <format> - set format lua, table, ttable or yaml (default)
• \set table_format <format> - set table format default, jira or markdown
• \set graphics <false/true> - disables/enables (default) pseudographics for table modes
• \set table_column_width <width> - set max column width for table/ttable
• \xw <width> - set max column width for table/ttable
• \x - switches output format cyclically
• \x[l,t,T,y] - set output format lua, table, ttable or yaml
• \x[g,G] - disables/enables pseudographics for table modes

Supported formats:

1. yaml - shows data as a YAML document. The format is used now by tarantool and tt.
2. lua - shows data as Lua-compatible structs.
3. table - shows data as a pseudo graphical table.
4. ttable - the same as the table format, but a result table is transposed (rotate data from rows to columns).

Supported table formats (for table or ttable formats):

1. default - shows data as a pseudo graphical table.
2. markdown - shows data as a Markdown-compatible table.
3. jira - shows data as a Jira-compatible table.

Example:

> \set output table
> box.space.customers:select()
+------+-----------+------+
| col1 | col2      | col3 |
+------+-----------+------+
| 1    | Elizabeth | 12   |
+------+-----------+------+
> \xg
> box.space.customers:select()
 col1  col2       col3 
 1     Elizabeth  12   
 2     Mary       46   
 3     David      33

[oleg-jukovec]

After discussion with @LeonidVas and @psergee we decided that an import of the go-pretty code should be done in a different way:

1. Create a patch for the latest release of the go-pretty. The patch should be as small as possible.
2. Add go-pretty as a git submodule.
3. Patch the submodule with the patch on the build step.

See how it is already done with cartridge-cli in the repo.

[oleg-jukovec]

Thank you for the update, I have a couple of questions about the go-pretty patching.

[oleg-jukovec]

Approved by mistake.

[oleg-jukovec]

I'm glad to see that we could resume without the go-pretty patching. Let's now focus on code style.

[oleg-jukovec]

Some more questions.

[GRISHNOV]

#535 (comment)

But it covered by integration tests, why duplicate?

[oleg-jukovec]

The critical lack of the implementation is the input data for the MakeOutput function inconsistent with all formats.

{ // Ok.
	formatter.DefaultFormat,
	"---\n- 1\n- 2\n- 3\n...",
	"---\n- 1\n- 2\n- 3\n...\n",
	false,
},
{ // Ok.
	formatter.TableFormat,
	"---\n- 1\n- 2\n- 3\n...",
	"+------+\n" +
		"| col1 |\n" +
		"+------+\n" +
		"| 1    |\n" +
		"+------+\n" +
		"| 2    |\n" +
		"+------+\n" +
		"| 3    |\n" +
		"+------+\n",
	false,
},
{ // The problem. It does not print a tuple.
	formatter.DefaultFormat,
	"---\n- DATA: 8\n  COLUMN_1: 30\n  FOO: 1\n  COLUMN_2: 50\n...",
	"---\n- DATA: 8\n  COLUMN_1: 30\n  FOO: 1\n  COLUMN_2: 50\n...\n",
	false,
},
{ // Ok.
	formatter.TableFormat,
	"---\n- DATA: 8\n  COLUMN_1: 30\n  FOO: 1\n  COLUMN_2: 50\n...\n",
	"+----------+----------+------+-----+\n" +
		"| COLUMN_1 | COLUMN_2 | DATA | FOO |\n" +
		"+----------+----------+------+-----+\n" +
		"| 30       | 50       | 8    | 1   |\n" +
		"+----------+----------+------+-----+\n",
	false,
},

As a user, I expect to pass a valid data to it, I will get a valid result as tuples for all formats. But in practice, not all formats can work with the same input data. As example, DefaultFormat/YamlFormat could not work with a data with fields names as expected (return tuples without field names in the format).

This will overсomplicate development in the future. We will need to build two different YAML documents for export tuples from IPROTO.

So we need to make sure that the same valid input is valid for all formats, and formatted correctly by them.

[oleg-jukovec]

I did a little code refactoring (but not tests refactoring). I suggest to forget about everything that happened before and start the review all over again.

[DerekBum]

Thanks for the patch! I've got some questions, please see the comments below.

Also, are changes from x = x + ... to x += ... and x++ considered as too sinister nits? I just think that it would be nice to see a uniform code style (and the method of addition differs from line to line).

[oleg-jukovec]

LGTM =)