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Transient prompt (#10391)

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## Description

This PR uses environment variables to enable and set a transient prompt,
which lets you draw a different prompt once you've entered a command and
you've moved on to the next line. This is useful if you have a fancy
two-line prompt with a bunch of info about time and git status that you
don't really need in your scrollback buffer.

Here's a screenshot. You can see how my usual prompt has two lines and
would take up a lot more space if every past command also used the full
prompt, but reducing past prompts to `🚀` or `>` makes it take up less
space.

![image](https://github.com/nushell/nushell/assets/45539777/dde8d0f5-f95f-4529-9a14-b7919bd51126)

I added the following lines to my `env.nu` to get that rocket as the
prompt initially:
```nu
$env.TRANSIENT_PROMPT_COMMAND = {|| "" }
$env.TRANSIENT_PROMPT_INDICATOR = {|| open --raw "~/.prompt-indicator" }
$env.TRANSIENT_PROMPT_INDICATOR_VI_INSERT = $env.TRANSIENT_PROMPT_INDICATOR
```

## User-Facing Changes

If you want to change a segment of the prompt, set the corresponding
`TRANSIENT_PROMPT_*` variable.

<!-- If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
-->

## Problems/Things to Consider:
- The transient prompt clones the `Stack` at the very beginning of the
session and keeps that around. I'm not sure if that could cause
problems, but if so, it could probably take an `Arc<State>` instead.
- This isn't truly a problem, but now there's even more environment
variables, which is kinda annoying.
- There might be some performance issues with creating a new
`NushellPrompt` object and cloning the `Stack` for every segment of the
transient prompt. What's more, the transient prompt is added to the
`Reedline` object whether or not the user has enabled transient prompt,
so if there are indeed performance issues, simply disabling the
transient prompt won't help.
- Perhaps instead of a separate `TRANSIENT_PROMPT_INDICATOR_VI_INSERT`
and `TRANSIENT_PROMPT_INDICATOR_VI_NORMAL`, `TRANSIENT_PROMPT_INDICATOR`
could be used for both (if it exists). Insert and normal mode don't
really matter for previously entered commands.
This commit is contained in:
Yash Thakur 2023-09-22 15:35:09 -04:00 committed by GitHub
parent 6df001f72d
commit 414216edfa
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 144 additions and 1 deletions
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127
crates/nu-cli/src/prompt_update.rs
View File

@ -7,6 +7,8 @@ use nu_protocol::{
Config, PipelineData, Value,
};
use reedline::Prompt;
use std::borrow::Cow;
use std::sync::Arc;
// Name of environment variable where the prompt could be stored
pub(crate) const PROMPT_COMMAND: &str = "PROMPT_COMMAND";
@ -15,6 +17,15 @@ pub(crate) const PROMPT_INDICATOR: &str = "PROMPT_INDICATOR";
pub(crate) const PROMPT_INDICATOR_VI_INSERT: &str = "PROMPT_INDICATOR_VI_INSERT";
pub(crate) const PROMPT_INDICATOR_VI_NORMAL: &str = "PROMPT_INDICATOR_VI_NORMAL";
pub(crate) const PROMPT_MULTILINE_INDICATOR: &str = "PROMPT_MULTILINE_INDICATOR";
pub(crate) const TRANSIENT_PROMPT_COMMAND: &str = "TRANSIENT_PROMPT_COMMAND";
pub(crate) const TRANSIENT_PROMPT_COMMAND_RIGHT: &str = "TRANSIENT_PROMPT_COMMAND_RIGHT";
pub(crate) const TRANSIENT_PROMPT_INDICATOR: &str = "TRANSIENT_PROMPT_INDICATOR";
pub(crate) const TRANSIENT_PROMPT_INDICATOR_VI_INSERT: &str =
"TRANSIENT_PROMPT_INDICATOR_VI_INSERT";
pub(crate) const TRANSIENT_PROMPT_INDICATOR_VI_NORMAL: &str =
"TRANSIENT_PROMPT_INDICATOR_VI_NORMAL";
pub(crate) const TRANSIENT_PROMPT_MULTILINE_INDICATOR: &str =
"TRANSIENT_PROMPT_MULTILINE_INDICATOR";
// According to Daniel Imms @Tyriar, we need to do these this way:
// <133 A><prompt><133 B><command><133 C><command output>
const PRE_PROMPT_MARKER: &str = "\x1b]133;A\x1b\\";
@ -145,3 +156,119 @@ pub(crate) fn update_prompt<'prompt>(
ret_val
}
struct TransientPrompt {
engine_state: Arc<EngineState>,
stack: Stack,
}
/// Try getting `$env.TRANSIENT_PROMPT_<X>`, and get `$env.PROMPT_<X>` if that fails
fn get_transient_prompt_string(
transient_prompt: &str,
prompt: &str,
config: &Config,
engine_state: &EngineState,
stack: &mut Stack,
) -> Option<String> {
get_prompt_string(transient_prompt, config, engine_state, stack)
.or_else(|| get_prompt_string(prompt, config, engine_state, stack))
}
impl Prompt for TransientPrompt {
fn render_prompt_left(&self) -> Cow<str> {
let mut nu_prompt = NushellPrompt::new();
let config = &self.engine_state.get_config().clone();
let mut stack = self.stack.clone();
nu_prompt.update_prompt_left(get_transient_prompt_string(
TRANSIENT_PROMPT_COMMAND,
PROMPT_COMMAND,
config,
&self.engine_state,
&mut stack,
));
nu_prompt.render_prompt_left().to_string().into()
}
fn render_prompt_right(&self) -> Cow<str> {
let mut nu_prompt = NushellPrompt::new();
let config = &self.engine_state.get_config().clone();
let mut stack = self.stack.clone();
nu_prompt.update_prompt_right(
get_transient_prompt_string(
TRANSIENT_PROMPT_COMMAND_RIGHT,
PROMPT_COMMAND_RIGHT,
config,
&self.engine_state,
&mut stack,
),
config.render_right_prompt_on_last_line,
);
nu_prompt.render_prompt_right().to_string().into()
}
fn render_prompt_indicator(&self, prompt_mode: reedline::PromptEditMode) -> Cow<str> {
let mut nu_prompt = NushellPrompt::new();
let config = &self.engine_state.get_config().clone();
let mut stack = self.stack.clone();
nu_prompt.update_prompt_indicator(get_transient_prompt_string(
TRANSIENT_PROMPT_INDICATOR,
PROMPT_INDICATOR,
config,
&self.engine_state,
&mut stack,
));
nu_prompt.update_prompt_vi_insert(get_transient_prompt_string(
TRANSIENT_PROMPT_INDICATOR_VI_INSERT,
PROMPT_INDICATOR_VI_INSERT,
config,
&self.engine_state,
&mut stack,
));
nu_prompt.update_prompt_vi_normal(get_transient_prompt_string(
TRANSIENT_PROMPT_INDICATOR_VI_NORMAL,
PROMPT_INDICATOR_VI_NORMAL,
config,
&self.engine_state,
&mut stack,
));
nu_prompt
.render_prompt_indicator(prompt_mode)
.to_string()
.into()
}
fn render_prompt_multiline_indicator(&self) -> Cow<str> {
let mut nu_prompt = NushellPrompt::new();
let config = &self.engine_state.get_config().clone();
let mut stack = self.stack.clone();
nu_prompt.update_prompt_multiline(get_transient_prompt_string(
TRANSIENT_PROMPT_MULTILINE_INDICATOR,
PROMPT_MULTILINE_INDICATOR,
config,
&self.engine_state,
&mut stack,
));
nu_prompt
.render_prompt_multiline_indicator()
.to_string()
.into()
}
fn render_prompt_history_search_indicator(
&self,
history_search: reedline::PromptHistorySearch,
) -> Cow<str> {
NushellPrompt::new()
.render_prompt_history_search_indicator(history_search)
.to_string()
.into()
}
}
/// Construct the transient prompt
pub(crate) fn transient_prompt(engine_state: Arc<EngineState>, stack: &Stack) -> Box<dyn Prompt> {
Box::new(TransientPrompt {
engine_state,
stack: stack.clone(),
})
}

6
crates/nu-cli/src/repl.rs
View File

@ -271,7 +271,11 @@ pub fn evaluate_repl(
.with_quick_completions(config.quick_completions)
.with_partial_completions(config.partial_completions)
.with_ansi_colors(config.use_ansi_coloring)
.with_cursor_config(cursor_config);
.with_cursor_config(cursor_config)
.with_transient_prompt(prompt_update::transient_prompt(
engine_reference.clone(),
stack,
));
perf(
"reedline builder",
start_time,

12
crates/nu-utils/src/sample_config/default_env.nu
View File

@ -47,6 +47,18 @@ $env.PROMPT_INDICATOR_VI_INSERT = {|| ": " }
$env.PROMPT_INDICATOR_VI_NORMAL = {|| "> " }
$env.PROMPT_MULTILINE_INDICATOR = {|| "::: " }
# If you want previously entered commands to have a different prompt from the usual one,
# you can uncomment one or more of the following lines.
# This can be useful if you have a 2-line prompt and it's taking up a lot of space
# because every command entered takes up 2 lines instead of 1. You can then uncomment
# the line below so that previously entered commands show with a single `🚀`.
# $env.TRANSIENT_PROMPT_COMMAND = {|| "🚀 " }
# $env.TRANSIENT_PROMPT_INDICATOR = {|| "" }
# $env.TRANSIENT_PROMPT_INDICATOR_VI_INSERT = {|| "" }
# $env.TRANSIENT_PROMPT_INDICATOR_VI_NORMAL = {|| "" }
# $env.TRANSIENT_PROMPT_MULTILINE_INDICATOR = {|| "" }
# $env.TRANSIENT_PROMPT_COMMAND_RIGHT = {|| "" }
# Specifies how environment variables are:
# - converted from a string to a value on Nushell startup (from_string)
# - converted from a value back to a string when running external commands (to_string)