fix(zsh): Set PROMPT just once (#2428)

No need to forcefully set the `PROMPT` variable every time the prompt is
to be shown. Just set it once, leaving the command to be evaluated every
time the prompt is to be shown, by enabling the `promptsubst` option.

Setting it once is also friendlier to users that want to experiment with
another prompt theme by temporarily setting `PROMPT` to something else.
This would currently not be possible, because the variable is always
reset before every prompt draw (precmd) and keymap change
(zle-keymap-select).

Some other updates to take better advantage of the zsh script dialect:

  * `$` is not required to read variables inside `(( ))` arithmetic
    expressions.
  * The zsh dialect to check if a variable is set is `${+var}`. Better
    than `${var+1}`, which substitutes 1 if var is set, which is
    intended for more general substitutions, not just to check if var is
    set.
  * The number of jobs can be read using the `%j` escape sequence, which
    is expanded when the `promptpercent` option is set.

Also simplified a couple of code lines by avoiding a temporary
`STARSHIP_START_TIME` variable, since we already have
`STARSHIP_CAPTURED_TIME`.
This commit is contained in:
Eric Nielsen 2021-03-15 05:39:35 -05:00 committed by GitHub
parent c91b293c9d
commit 6fd7d7b501
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@ -7,15 +7,6 @@
# after drawing the prompt. This ensures that the timing for one command is only
# ever drawn once (for the prompt immediately after it is run).
zmodload zsh/parameter # Needed to access jobstates variable for NUM_JOBS
starship_render() {
# Use length of jobstates array as number of jobs. Expansion fails inside
# quotes so we set it here and then use the value later on.
NUM_JOBS=$#jobstates
PROMPT="$(::STARSHIP:: prompt --keymap="${KEYMAP-}" --status=$STARSHIP_CMD_STATUS --cmd-duration=${STARSHIP_DURATION-} --jobs="$NUM_JOBS")"
}
# Defines a function `__starship_get_time` that sets the time since epoch in millis in STARSHIP_CAPTURED_TIME.
if [[ $ZSH_VERSION == ([1-4]*) ]]; then
# ZSH <= 5; Does not have a built-in variable so we will rely on Starship's inbuilt time function.
@ -26,7 +17,7 @@ else
zmodload zsh/datetime
zmodload zsh/mathfunc
__starship_get_time() {
((STARSHIP_CAPTURED_TIME = int(rint($EPOCHREALTIME * 1000))))
(( STARSHIP_CAPTURED_TIME = int(rint(EPOCHREALTIME * 1000)) ))
}
fi
@ -37,16 +28,12 @@ starship_precmd() {
# Compute cmd_duration, if we have a time to consume, otherwise clear the
# previous duration
if [[ -n "${STARSHIP_START_TIME+1}" ]]; then
__starship_get_time && STARSHIP_END_TIME=$STARSHIP_CAPTURED_TIME
((STARSHIP_DURATION = STARSHIP_END_TIME - STARSHIP_START_TIME))
if (( ${+STARSHIP_START_TIME} )); then
__starship_get_time && (( STARSHIP_DURATION = STARSHIP_CAPTURED_TIME - STARSHIP_START_TIME ))
unset STARSHIP_START_TIME
else
unset STARSHIP_DURATION
fi
# Render the updated prompt
starship_render
}
starship_preexec() {
__starship_get_time && STARSHIP_START_TIME=$STARSHIP_CAPTURED_TIME
@ -55,8 +42,8 @@ starship_preexec() {
# If precmd/preexec arrays are not already set, set them. If we don't do this,
# the code to detect whether starship_precmd is already in precmd_functions will
# fail because the array doesn't exist (and same for starship_preexec)
[[ -z "${precmd_functions+1}" ]] && precmd_functions=()
[[ -z "${preexec_functions+1}" ]] && preexec_functions=()
(( ! ${+precmd_functions} )) && precmd_functions=()
(( ! ${+preexec_functions} )) && preexec_functions=()
# If starship precmd/preexec functions are already hooked, don't double-hook them
# to avoid unnecessary performance degradation in nested shells
@ -69,7 +56,6 @@ fi
# Set up a function to redraw the prompt if the user switches vi modes
starship_zle-keymap-select() {
starship_render
zle reset-prompt
}
@ -96,3 +82,8 @@ export STARSHIP_SHELL="zsh"
STARSHIP_SESSION_KEY="$RANDOM$RANDOM$RANDOM$RANDOM$RANDOM"; # Random generates a number b/w 0 - 32767
STARSHIP_SESSION_KEY="${STARSHIP_SESSION_KEY}0000000000000000" # Pad it to 16+ chars.
export STARSHIP_SESSION_KEY=${STARSHIP_SESSION_KEY:0:16}; # Trim to 16-digits if excess.
VIRTUAL_ENV_DISABLE_PROMPT=1
setopt prompt{percent,subst}
PROMPT='$(::STARSHIP:: prompt --keymap=${KEYMAP} --status=${STARSHIP_CMD_STATUS} --cmd-duration=${STARSHIP_DURATION} --jobs=%j)'