feat: Implement a two-phase init which allows us to write normal init scripts (#168)
Implement a two-phase init procedure in starship. The first phase causes the shell to source a subshell, while the second phase (in the subshell) prints the main init script. This allows us to have nice init scripts with good styling, comments, and no pile of semicolons. Even better, it works as a drop-in replacement, so we don't need to update the docs.
This commit is contained in:
Kevin Song
GitHub
parent
2e39c6d0fa
commit
0e82c19f37
260
src/init.rs
260
src/init.rs
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@ -1,26 +1,39 @@
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use std::ffi::OsStr;
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use std::ffi::OsStr;
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use std::path::Path;
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use std::path::Path;
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/* We need to send execution time to the prompt for the cmd_duration module. For fish,
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/* We use a two-phase init here: the first phase gives a simple command to the
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this is fairly straightforward. For bash and zsh, we'll need to use several
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shell. This command evaluates a more complicated script using `source` and
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shell utilities to get the time, as well as render the prompt */
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process substitution.
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pub fn init(shell_name: &str) {
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Directly using `eval` on a shell script causes it to be evaluated in
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a single line, which sucks because things like comments will comment out the
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rest of the script, and you have to spam semicolons everywhere. By using
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source and process substitutions, we make it possible to comment and debug
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the init scripts. */
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/* This prints the setup stub, the short piece of code which sets up the main
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init code. The stub produces the main init script, then evaluates it with
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`source` and process substitution */
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pub fn init_stub(shell_name: &str) {
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log::debug!("Shell name: {}", shell_name);
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log::debug!("Shell name: {}", shell_name);
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let shell_basename = Path::new(shell_name).file_stem().and_then(OsStr::to_str);
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let shell_basename = Path::new(shell_name).file_stem().and_then(OsStr::to_str);
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let setup_script = match shell_basename {
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let setup_stub = match shell_basename {
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Some("bash") => {
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Some("bash") => {
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let script = BASH_INIT;
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/* This *should* look like the zsh function, but bash 3.2 (MacOS default shell)
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does not support using source with process substitution, so we use this
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workaround from https://stackoverflow.com/a/32596626 */
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let script = "source /dev/stdin <<<\"$(starship init bash --print-full-init)\"";
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Some(script)
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Some(script)
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}
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}
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Some("zsh") => {
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Some("zsh") => {
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let script = ZSH_INIT;
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let script = "source <(starship init zsh --print-full-init)";
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Some(script)
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Some(script)
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}
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}
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Some("fish") => {
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Some("fish") => {
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let script = FISH_INIT;
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// Fish does process substitution with pipes and psub instead of bash syntax
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let script = "source (starship init fish --print-full-init | psub)";
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Some(script)
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Some(script)
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}
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}
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None => {
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None => {
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@ -46,142 +59,179 @@ pub fn init(shell_name: &str) {
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None
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None
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}
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}
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};
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};
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if let Some(script) = setup_stub {
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if let Some(script) = setup_script {
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print!("{}", script);
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print!("{}", script);
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}
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};
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}
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}
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/*
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/* This function (called when `--print-full-init` is passed to `starship init`)
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For bash: we need to manually hook functions ourself: PROMPT_COMMAND will exec
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prints out the main initialization script */
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right before the prompt is drawn, and any function trapped by DEBUG will exec
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pub fn init_main(shell_name: &str) {
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before a command is run.
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let setup_script = match shell_name {
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"bash" => Some(BASH_INIT),
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"zsh" => Some(ZSH_INIT),
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"fish" => Some(FISH_INIT),
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_ => {
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println!(
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"printf \"Shell name detection failed on phase two init.\\n\
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This probably indicates a bug within starship: please open\\n\
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an issue at https://github.com/starship/starship/issues/new\\n\""
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);
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None
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}
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};
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if let Some(script) = setup_script {
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print!("{}", script);
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};
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}
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There is a preexec/precmd framework for bash out there: if we find the
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/* GENERAL INIT SCRIPT NOTES
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appropriate variables set, assume we are using that framework:
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https://github.com/rcaloras/bash-preexec
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Bash quirk: DEBUG is triggered whenever a command is executed, even if that
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Each init script will be passed as-is. Global notes for init scripts are in this
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command is part of a pipeline. To avoid only timing the last part of a pipeline,
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comment, with additional per-script comments in the strings themselves.
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we only start the timer if no timer has been started since the last prompt draw,
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tracked by the variable PREEXEC_READY. Similarly, only draw timing info if
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STARSHIP_START_TIME is defined, in case preexec was interrupted.
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Finally, to work around existing DEBUG traps in the absence of a preexec-like,
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JOBS: The argument to `--jobs` is quoted because MacOS's `wc` leaves whitespace
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we parse out the name of the old DEBUG hook, then make a new function which
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in the output. We pass it to starship and do the whitespace removal in Rust,
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calls both that function and our starship hooks. We don't do this for
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to avoid the cost of an additional shell fork every shell draw.
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PROMPT_COMMAND because that would probably result in two prompts.
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We need to quote the output of `$(jobs -p | wc -l)` since MacOS `wc` leaves
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giant spaces in front of the number (e.g. " 3"), which messes up the
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word-splitting. Instead, quote the whole thing, then let Rust do the whitespace
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trimming within the jobs module
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*/
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*/
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/*
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/* BASH INIT SCRIPT
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Note to programmers: this and the zsh init will be evaluated on a single line.
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Use semicolons, avoid comments, and generally think like all newlines will be
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We use PROMPT_COMMAND and the DEBUG trap to generate timing information. We try
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deleted.
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to avoid clobbering what we can, and try to give the user ways around our
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clobbers, if it's unavoidable.
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A bash quirk is that the DEBUG trap is fired every time a command runs, even
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if it's later on in the pipeline. If uncorrected, this could cause bad timing
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data for commands like `slow | slow | fast`, since the timer starts at the start
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of the "fast" command.
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To solve this, we set a flag `PREEXEC_READY` when the prompt is drawn, and only
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start the timer if this flag is present. That way, timing is for the entire command,
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and not just a portion of it
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*/
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*/
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const BASH_INIT: &str = r##"
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const BASH_INIT: &str = r##"
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# Will be run before *every* command (even ones in pipes!)
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starship_preexec() {
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starship_preexec() {
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# Avoid restarting the timer for commands in the same pipeline
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if [ "$PREEXEC_READY" = "true" ]; then
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if [ "$PREEXEC_READY" = "true" ]; then
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PREEXEC_READY=false;
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PREEXEC_READY=false
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STARSHIP_START_TIME=$(date +%s);
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STARSHIP_START_TIME=$(date +%s)
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fi
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fi
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};
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}
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# Will be run before the prompt is drawn
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starship_precmd() {
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starship_precmd() {
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STATUS=$?;
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# Save the status, because commands in this pipeline will change $?
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export STARSHIP_SHELL="bash";
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STATUS=$?
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"${starship_precmd_user_func-:}";
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# Run the bash precmd function, if it's set. If not set, evaluates to no-op
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"${starship_precmd_user_func-:}"
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# Prepare the timer data, if needed.
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if [[ $STARSHIP_START_TIME ]]; then
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if [[ $STARSHIP_START_TIME ]]; then
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STARSHIP_END_TIME=$(date +%s);
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STARSHIP_END_TIME=$(date +%s)
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STARSHIP_DURATION=$((STARSHIP_END_TIME - STARSHIP_START_TIME));
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STARSHIP_DURATION=$((STARSHIP_END_TIME - STARSHIP_START_TIME))
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PS1="$(starship prompt --status=$STATUS --jobs="$(jobs -p | wc -l)" --cmd-duration=$STARSHIP_DURATION)";
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PS1="$(starship prompt --status=$STATUS --jobs="$(jobs -p | wc -l)" --cmd-duration=$STARSHIP_DURATION)"
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unset STARSHIP_START_TIME;
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unset STARSHIP_START_TIME
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else
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else
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PS1="$(starship prompt --status=$STATUS --jobs="$(jobs -p | wc -l)")";
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PS1="$(starship prompt --status=$STATUS --jobs="$(jobs -p | wc -l)")"
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fi;
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fi
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PREEXEC_READY=true;
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PREEXEC_READY=true; # Signal that we can safely restart the timer
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};
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}
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# If the user appears to be using https://github.com/rcaloras/bash-preexec,
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# then hook our functions into their framework.
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if [[ $preexec_functions ]]; then
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if [[ $preexec_functions ]]; then
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preexec_functions+=(starship_preexec);
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preexec_functions+=(starship_preexec)
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precmd_functions+=(starship_precmd);
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precmd_functions+=(starship_precmd)
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STARSHIP_START_TIME=$(date +%s);
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else
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else
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dbg_trap="$(trap -p DEBUG | cut -d' ' -f3 | tr -d \')";
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# We want to avoid destroying an existing DEBUG hook. If we detect one, create
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# a new function that runs both the existing function AND our function, then
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# re-trap DEBUG to use this new function. This prevents a trap clobber.
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dbg_trap="$(trap -p DEBUG | cut -d' ' -f3 | tr -d \')"
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if [[ -z "$dbg_trap" ]]; then
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if [[ -z "$dbg_trap" ]]; then
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trap starship_preexec DEBUG;
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trap starship_preexec DEBUG
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elif [[ "$dbg_trap" != "starship_preexec" && "$dbg_trap" != "starship_preexec_all" ]]; then
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elif [[ "$dbg_trap" != "starship_preexec" && "$dbg_trap" != "starship_preexec_all" ]]; then
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function starship_preexec_all(){
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function starship_preexec_all(){
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$dbg_trap; starship_preexec;
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$dbg_trap; starship_preexec
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};
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}
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trap starship_preexec_all DEBUG;
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trap starship_preexec_all DEBUG
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fi;
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fi
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PROMPT_COMMAND=starship_precmd;
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STARSHIP_START_TIME=$(date +%s);
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# Finally, prepare the precmd function and set up the start time.
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fi;
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PROMPT_COMMAND=starship_precmd
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fi
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# Set up the start time and STARSHIP_SHELL, which controls shell-specific sequences
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STARSHIP_START_TIME=$(date +%s)
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export STARSHIP_SHELL="bash"
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"##;
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"##;
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/* For zsh: preexec_functions and precmd_functions provide preexec/precmd in a
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/* ZSH INIT SCRIPT
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way that lets us avoid clobbering them.
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Zsh quirk: preexec() is only fired if a command is actually run (unlike in
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ZSH has a quirk where `preexec` is only run if a command is actually run (i.e
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bash, where spamming empty commands still triggers DEBUG). This means a user
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pressing ENTER at an empty command line will not cause preexec to fire). This
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spamming ENTER at an empty command line will see increasing runtime (since
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can cause timing issues, as a user who presses "ENTER" without running a command
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preexec never actually fires to reset the start time).
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will see the time to the start of the last command, which may be very large.
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To fix this, only pass the time if STARSHIP_START_TIME is defined, and unset
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To fix this, we create STARSHIP_START_TIME upon preexec() firing, and destroy it
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it after passing the time, so that we only measure actual commands.
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after drawing the prompt. This ensures that the timing for one command is only
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ever drawn once (for the prompt immediately after it is run).
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We need to quote the output of the jobs command for the same reason as
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bash.
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*/
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*/
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const ZSH_INIT: &str = r##"
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const ZSH_INIT: &str = r##"
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# Will be run before every prompt draw
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starship_precmd() {
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starship_precmd() {
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STATUS=$?;
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# Save the status, because commands in this pipeline will change $?
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export STARSHIP_SHELL="zsh";
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STATUS=$?
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# Compute cmd_duration, if we have a time to consume
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if [[ $STARSHIP_START_TIME ]]; then
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if [[ $STARSHIP_START_TIME ]]; then
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STARSHIP_END_TIME="$(date +%s)";
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STARSHIP_END_TIME="$(date +%s)"
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STARSHIP_DURATION=$((STARSHIP_END_TIME - STARSHIP_START_TIME));
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STARSHIP_DURATION=$((STARSHIP_END_TIME - STARSHIP_START_TIME))
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PROMPT="$(starship prompt --status=$STATUS --cmd-duration=$STARSHIP_DURATION --jobs="$(jobs | wc -l)")";
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PROMPT="$(starship prompt --status=$STATUS --cmd-duration=$STARSHIP_DURATION --jobs="$(jobs | wc -l)")"
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unset STARSHIP_START_TIME;
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unset STARSHIP_START_TIME
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else
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else
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PROMPT="$(starship prompt --status=$STATUS --jobs="$(jobs | wc -l)")";
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PROMPT="$(starship prompt --status=$STATUS --jobs="$(jobs | wc -l)")"
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fi
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fi
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};
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}
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starship_preexec(){
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starship_preexec(){
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STARSHIP_START_TIME="$(date +%s)"
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STARSHIP_START_TIME="$(date +%s)"
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};
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}
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if [[ -z "${precmd_functions+1}" ]]; then
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precmd_functions=()
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# If precmd/preexec arrays are not already set, set them. If we don't do this,
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fi;
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# the code to detect whether starship_precmd is already in precmd_functions will
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if [[ -z "${preexec_functions+1}" ]]; then
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# fail because the array doesn't exist (and same for starship_preexec)
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preexec_functions=()
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[[ -z "${precmd_functions+1}" ]] && precmd_functions=()
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fi;
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[[ -z "${preexec_functions+1}" ]] && preexec_functions=()
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# If starship precmd/preexec functions are already hooked, don't double-hook them
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# to avoid unnecessary performance degradation in nested shells
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if [[ ${precmd_functions[(ie)starship_precmd]} -gt ${#precmd_functions} ]]; then
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if [[ ${precmd_functions[(ie)starship_precmd]} -gt ${#precmd_functions} ]]; then
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precmd_functions+=(starship_precmd);
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precmd_functions+=(starship_precmd)
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fi;
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fi
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if [[ ${preexec_functions[(ie)starship_preexec]} -gt ${#preexec_functions} ]]; then
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if [[ ${preexec_functions[(ie)starship_preexec]} -gt ${#preexec_functions} ]]; then
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preexec_functions+=(starship_preexec);
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preexec_functions+=(starship_preexec)
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fi;
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fi
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STARSHIP_START_TIME="$(date +%s)";
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# Set up a function to redraw the prompt if the user switches vi modes
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function zle-keymap-select
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function zle-keymap-select
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{
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{
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PROMPT=$(starship prompt --keymap=$KEYMAP --jobs="$(jobs | wc -l)");
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PROMPT=$(starship prompt --keymap=$KEYMAP --jobs="$(jobs | wc -l)")
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zle reset-prompt;
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zle reset-prompt
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};
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}
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zle -N zle-keymap-select;
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STARSHIP_START_TIME="$(date +%s)"
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zle -N zle-keymap-select
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export STARSHIP_SHELL="zsh"
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"##;
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"##;
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/* Fish setup is simple because they give us CMD_DURATION. Just account for name
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changes between 2.7/3.0 and do some math to convert ms->s and we can use it */
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const FISH_INIT: &str = r##"
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const FISH_INIT: &str = r##"
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function fish_prompt;
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function fish_prompt
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set -l exit_code $status;
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set -l exit_code $status
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set -l CMD_DURATION "$CMD_DURATION$cmd_duration";
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# Account for changes in variable name between v2.7 and v3.0
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set -l starship_duration (math --scale=0 "$CMD_DURATION / 1000");
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set -l CMD_DURATION "$CMD_DURATION$cmd_duration"
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starship prompt --status=$exit_code --cmd-duration=$starship_duration --jobs=(count (jobs -p));
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set -l starship_duration (math --scale=0 "$CMD_DURATION / 1000")
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end;
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starship prompt --status=$exit_code --cmd-duration=$starship_duration --jobs=(count (jobs -p))
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end
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"##;
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"##;
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13
src/main.rs
13
src/main.rs
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@ -58,6 +58,10 @@ fn main() {
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.help("The number of currently running jobs")
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.help("The number of currently running jobs")
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.takes_value(true);
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.takes_value(true);
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let init_scripts_arg = Arg::with_name("print_full_init")
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.long("print-full-init")
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.help("Print the main initialization script (as opposed to the init stub)");
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let matches = App::new("starship")
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let matches = App::new("starship")
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.about("The cross-shell prompt for astronauts. ☄🌌️")
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.about("The cross-shell prompt for astronauts. ☄🌌️")
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// pull the version number from Cargo.toml
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// pull the version number from Cargo.toml
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@ -69,7 +73,8 @@ fn main() {
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.subcommand(
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.subcommand(
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SubCommand::with_name("init")
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SubCommand::with_name("init")
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.about("Prints the shell function used to execute starship")
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.about("Prints the shell function used to execute starship")
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.arg(&shell_arg),
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.arg(&shell_arg)
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.arg(&init_scripts_arg),
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)
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)
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.subcommand(
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.subcommand(
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SubCommand::with_name("prompt")
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SubCommand::with_name("prompt")
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|
@ -99,7 +104,11 @@ fn main() {
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match matches.subcommand() {
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match matches.subcommand() {
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("init", Some(sub_m)) => {
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("init", Some(sub_m)) => {
|
||||||
let shell_name = sub_m.value_of("shell").expect("Shell name missing.");
|
let shell_name = sub_m.value_of("shell").expect("Shell name missing.");
|
||||||
init::init(shell_name)
|
if sub_m.is_present("print_full_init") {
|
||||||
|
init::init_main(shell_name);
|
||||||
|
} else {
|
||||||
|
init::init_stub(shell_name);
|
||||||
|
}
|
||||||
}
|
}
|
||||||
("prompt", Some(sub_m)) => print::prompt(sub_m.clone()),
|
("prompt", Some(sub_m)) => print::prompt(sub_m.clone()),
|
||||||
("module", Some(sub_m)) => {
|
("module", Some(sub_m)) => {
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue