Add the prompt view customization ability

[apodkutin]

By default prompt has these segments: prompt_status, prompt_context, prompt_virtualenv, prompt_dir, prompt_git, prompt_end in that particular order.

If you want to add, change the order or remove some segments of the prompt, you can use array environment variable named AGNOSTER_PROMPT_SEGMENTS.

Examples:

• Show all segments of the prompt with indices:

  echo "${(F)AGNOSTER_PROMPT_SEGMENTS[@]}" | cat -n

• Add the new segment of the prompt to the beginning:

  AGNOSTER_PROMPT_SEGMENTS=("prompt_git" "${AGNOSTER_PROMPT_SEGMENTS[@]}")

• Add the new segment of the prompt to the end:

  AGNOSTER_PROMPT_SEGMENTS+="prompt_end"

• Insert the new segment of the prompt = PROMPT_SEGMENT_NAME on the particular position = PROMPT_SEGMENT_POSITION:

  PROMPT_SEGMENT_POSITION=5 PROMPT_SEGMENT_NAME="prompt_end";\
  AGNOSTER_PROMPT_SEGMENTS=("${AGNOSTER_PROMPT_SEGMENTS[@]:0:$PROMPT_SEGMENT_POSITION-1}" "$PROMPT_SEGMENT_NAME" "${AGNOSTER_PROMPT_SEGMENTS[@]:$PROMPT_SEGMENT_POSITION-1}");\
  unset PROMPT_SEGMENT_POSITION PROMPT_SEGMENT_NAME

• Swap segments 4th and 5th:

  SWAP_SEGMENTS=(4 5);\
  TMP_VAR="$AGNOSTER_PROMPT_SEGMENTS[$SWAP_SEGMENTS[1]]"; AGNOSTER_PROMPT_SEGMENTS[$SWAP_SEGMENTS[1]]="$AGNOSTER_PROMPT_SEGMENTS[$SWAP_SEGMENTS[2]]"; AGNOSTER_PROMPT_SEGMENTS[$SWAP_SEGMENTS[2]]="$TMP_VAR"
  unset SWAP_SEGMENTS TMP_VAR

• Remove the 5th segment:

  AGNOSTER_PROMPT_SEGMENTS[5]=

A small demo of the dummy custom prompt segment, which has been created with help of the built-in prompt_segment() function from Agnoster theme:

# prompt_segment() - Takes two arguments, background and foreground.
# Both can be omitted, rendering default background/foreground.

customize_agnoster() {
  prompt_segment 'red' '' ' ⚙ ⚡⚡⚡ ⚙  '
}

[apjanke]

I like it! This looks like a good approach to making the whole prompt more customizable.

One niggle: I would personally call the variable AGNOSTER_PROMPT_SEGMENTS instead of AGNOSTER_PROMPT, since a <foo>_PROMPT variable is usually a single formatted non-array string variable that defines a prompt, instead of an array.

Really good PR write-up too; kudos to you.

[agnoster]

Yes, this looks great! I agree with @apjanke re: naming, (AGNOSTER_PROMPT_SEGMENTS would be a better name for the config variable), with that change I'd be happy to merge.

Also +1 to the write-up.

[apodkutin]

@apjanke, @agnoster Thank you guys! I will do it today.

[apodkutin]

Thank you @MichaelAquilina ! @apjanke, @agnoster PR has been updated.

There is also PR in oh-my-zsh repository, if you are interested in https://github.com/robbyrussell/oh-my-zsh/pull/7355

[agnoster]

Small note: it looks like in the GIF demo there's something wrong with the color of the triangular segments - the very first one should be blue to match the directory, but appears black in the capture. Which terminal / color scheme are you using? I don't think it's related to the change here, but it'd be nice if the GIF demonstrating the feature had the right colors. For an example of what the prompt ought to look like, see:

[apodkutin]

Good catch @agnoster, I'm using iterm2/Solarized dark. I will fix it and will make a new recording of the demo.

And about your proposal regarding status>context>virtualenv>dir>git> config, I will try to implement it in the next PR.

[apodkutin]

@agnoster, GIF demo recording has been updated.

[agnoster]

Thanks again, this is wonderful!