Provide a context manager for automatically setting indentation levels when printing

[ruancomelli]

Hello, everyone! Before anything else, I'd like to compliment you all for this awesome project and community.

What

I'd like to discuss with you the possibility of including a context manager for automatically indenting text. For instance, the snippet

from rich.console import Console

console = Console()

console.print("Top marketcap cryptos:")
with console.indent():
    console.print("* BTC")
    console.print("* ETH")
console.print("Cool, huh?")

should output

Top marketcap cryptos:
    * BTC
    * ETH
Cool, huh?

Of course, one should be able to customize the indentation characters, and the context manager should be reentrant:

console.print("Your wallet:")
with console.indent("++++++"):
    console.print("BTC:")
    with console.indent("..."):
        console.print("Amount: 31.4")
        console.print("Last bought: yesterday")
    console.print("ETH:")
    with console.indent("-*-"):
        console.print("Amount: 15.9")
        console.print("Last bought: today")
console.print("You're [bold]rich[/bold]!!!")

Output:

Your wallet:
++++++BTC:
++++++...Amount: 31.4
++++++...Last bought: yesterday
++++++ETH:
++++++-*-Amount: 15.9
++++++-*-Last bought: today
You're rich!!!

Why

More than once, when writing (very small) CLI applications, I got something along the following lines:

console = Console()

wallets = {
  "BTC": { "amount": 31.4, "last_bought": "yesterday"},
  ...
}

def print_wallets():
    console.print('Your wallet:')
    print_amount('BTC', indentation=' '*4)
    print_amount('ETH', indentation=' '*4)

def print_amount(coin: str, indentation: str = "") -> None:
  nested_indentation = indentation + ' '*4

  console.print(f'{indentation}{coin}:')
  console.print(f'{indentation}{nested_indentation}Amount: {wallets[coin]["amount"]}:')
  console.print(f'{indentation}{nested_indentation}Last bought: {wallets[coin]["last_bought"]}:')

But things get complicated very fast because of that indentation parameter that has to be passed around all the time. If I could customize the indentation level outside of the function (in the console object, for instance), and have only the console itself being forwarded between functions (or even define it globally, as I do in most cases), things would look much simpler:

def print_wallets():
    console.print('Your wallet:')
    with console.indent(' '*4):
        print_amount('BTC')
        print_amount('ETH')

def print_amount(coin: str) -> None:
    console.print(f'{coin}:')
    with console.indent(' '*4):
        console.print(f'Amount: {wallets[coin]["amount"]}:')
        console.print(f'Last bought: {wallets[coin]["last_bought"]}:')

How

I'm really a newbie to Rich, so I won't even guess how to start implementing such functionality. I'll leave feasibility/difficulty/usefulness for you people to judge 😁

But, if you are interested, I have a draft implementation here:

from contextlib import contextmanager
from typing import Iterator, List

from rich.console import Console


class IndentableConsole(Console):
    def __init__(self, *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)

        self._indents: List[str] = []

    def print(self, *args, **kwargs) -> None:
        indent = "".join(self._indents)
        super().print(indent, *args, **kwargs)

    @contextmanager
    def indent(self, indent: str = '\t') -> Iterator[None]:
        self._indents.append(indent)
        yield
        self._indents.pop()

It works almost as expected, except that IndentableConsole.print inserts a sep between the indentation marks and the text we want to print. I believe it is just a matter of playing with the arguments, but I haven't taken the time to do it yet.