Add theme-preview.sh

This tool "hacks" Liquidprompt to get it to display exactly what we
want. This allows for completely reproducable outputs, to make
generating theme previews easy. These previews can be added to theme
documentation. By having stable values in this script, users can quickly
compare between themes, as they know the data behind the theme is the
same.

Run these commands to see what I mean:
./tools/theme-preview.sh default
./tools/theme-preview.sh powerline themes/powerline/powerline.theme
./tools/theme-preview.sh powerline_full themes/powerline/powerline.theme

Add a flag to lp_activate() to not load a config file. This will be
needed for tests in the future, so no harm adding it now.

liquidprompt

@@ -302,6 +302,9 @@ __lp_source_config() {
     # Debugging flags
     LP_DEBUG_TIME=${LP_DEBUG_TIME:-0}
 
+    if [[ ${1-} == --no-config ]]; then
+        return
+    fi
 
     # Default config file may be the XDG standard ~/.config/liquidpromptrc,
     # but heirloom dotfile has priority.
@@ -422,7 +425,7 @@ lp_activate() {
     # If tput doesn't exist or lookup failed, still try to send bell
     _LP_TI_BELL=${_LP_TI_BELL:-$'\a'}
 
-    __lp_source_config
+    __lp_source_config "$@"
 
     # Disable feature if the tool is not installed
     _lp_require_tool()

tools/theme-preview.sh

@@ -0,0 +1,222 @@
+#!/bin/bash
+set -u
+
+. liquidprompt --no-activate
+
+# If a theme was given, use the theme and source all other arguments.
+if [[ -z ${1-} || $1 == --help ]]; then
+  printf '
+Usage: %s theme [sourced files...]
+
+Print out example prompts based on a standard set of input conditions. Designed
+to showcase Liquidprompt themes.
+
+Example usage: %s powerline themes/powerline/powerline.theme
+' "$0" "$0"
+  exit 1
+
+else
+  theme=$1
+  shift
+
+  for file in "$@"; do
+    . "$file"
+  done
+fi
+
+# Liquidprompt depends on PS1 being set to detect if it has installed itself.
+PS1="$ "
+
+# Since the shell is not evaluating PS1, we don't need these.
+_LP_OPEN_ESC=""
+_LP_CLOSE_ESC=""
+
+
+## Short
+
+# Configure options
+
+LP_ENABLE_PERM=0
+LP_ENABLE_SHORTEN_PATH=1
+LP_ENABLE_PROXY=0
+LP_ENABLE_TEMP=0
+LP_ENABLE_JOBS=0
+LP_ENABLE_DETACHED_SESSIONS=0
+LP_ENABLE_LOAD=0
+LP_ENABLE_BATT=0
+LP_ENABLE_GIT=0
+LP_ENABLE_SVN=0
+LP_ENABLE_FOSSIL=0
+LP_ENABLE_HG=0
+LP_ENABLE_BZR=0
+LP_ENABLE_TIME=0
+LP_ENABLE_RUNTIME=0
+LP_ENABLE_RUNTIME_BELL=0
+LP_ENABLE_VIRTUALENV=0
+LP_ENABLE_SCLS=0
+LP_ENABLE_VCS_ROOT=1
+LP_DISABLED_VCS_PATHS=()
+LP_ENABLE_TITLE=0
+LP_ENABLE_SUDO=0
+LP_ENABLE_COLOR=1
+LP_ENABLE_ERROR=0
+LP_USER_ALWAYS=1
+LP_HOSTNAME_ALWAYS=-1
+
+LP_MARK_DEFAULT='$'
+
+# Stub data functions
+
+_lp_username() {
+  lp_username=user
+}
+
+# Setup Env
+
+HOME=/home/user
+PWD=$HOME
+
+# Activate and generate
+
+lp_activate --no-config
+# Only needs to be done once
+lp_theme "$theme"
+__lp_set_prompt
+
+printf 'Short prompt:\n\n  %s  \n\n' "$PS1"
+
+
+## Medium
+
+# Configure options
+
+# lp_activate() is too smart: it will disable features if the tool is not installed.
+# To make sure that doesn't happen, set these config options after activation too.
+_config() {
+  LP_ENABLE_JOBS=1
+  LP_HOSTNAME_ALWAYS=1
+  LP_ENABLE_GIT=1
+}
+_config
+
+# Stub data functions
+
+_lp_jobcount() {
+  lp_running_jobs=1
+  lp_stopped_jobs=0
+}
+_lp_hostname() {
+  _lp_connection
+  lp_hostname=server
+}
+_lp_connection() {
+  lp_connection=ssh
+}
+_lp_connected_display() { return 1; }
+_lp_find_vcs() {
+  lp_vcs_type=git
+  lp_vcs_root=$PWD
+}
+_lp_git_active() { return 0; }
+_lp_git_branch() {
+  lp_vcs_branch=main
+}
+_lp_git_bookmark() { return 2; }
+_lp_git_tag() { return 2; }
+_lp_git_commit_id() { return 2; }
+_lp_git_head_status() { return 2; }
+_lp_git_stash_count() { return 2; }
+_lp_git_commits_off_remote() { return 2; }
+_lp_git_untracked_files() { return 2; }
+_lp_git_uncommitted_files() { return 2; }
+_lp_git_uncommitted_lines() { return 2; }
+_lp_git_unstaged_files() { return 2; }
+_lp_git_unstaged_lines() { return 2; }
+
+# Setup Env
+
+PWD=$HOME/liquidprompt
+
+# Activate and generate
+
+lp_activate --no-config
+_config
+__lp_set_prompt
+
+printf 'Medium prompt:\n\n  %s  \n\n' "$PS1"
+
+
+## Long
+
+# Configure options
+
+_config() {
+  LP_ENABLE_TIME=1
+  LP_TIME_ANALOG=1
+  LP_ENABLE_BATT=1
+  LP_ENABLE_LOAD=1
+  LP_ENABLE_TEMP=1
+  LP_ENABLE_DETACHED_SESSIONS=1
+  LP_ENABLE_PERM=1
+  LP_ENABLE_VIRTUALENV=1
+  LP_ENABLE_RUNTIME=1
+  LP_ENABLE_ERROR=1
+  LP_PERCENTS_ALWAYS=1
+}
+_config
+
+# Stub data functions
+
+_lp_analog_time() {
+  lp_analog_time="🕤"
+}
+_lp_battery() {
+  lp_battery=24
+}
+_lp_load() {
+  lp_load=42
+}
+_lp_temperature() {
+  lp_temperature=90
+}
+_lp_detached_sessions() {
+  lp_detached_sessions=3
+}
+_lp_jobcount() {
+  lp_running_jobs=2
+  lp_stopped_jobs=1
+}
+__lp_shorten_path() {
+  lp_shorten_path="~${LP_MARK_SHORTEN_PATH}/code/liquidprompt"
+}
+_lp_python_env() {
+  lp_python_env=pyenv
+}
+_lp_git_uncommitted_lines() {
+  lp_vcs_uncommitted_i_lines=10
+  lp_vcs_uncommitted_d_lines=5
+}
+_lp_git_commits_off_remote() {
+  lp_vcs_commit_ahead=3
+  lp_vcs_commit_behind=1
+}
+_lp_git_stash_count() {
+  lp_vcs_stash_count=1
+}
+_lp_git_untracked_files() {
+  lp_vcs_untracked_files=1
+}
+_lp_runtime_format() {
+  lp_runtime_format=20s
+}
+_lp_error() {
+  lp_error=125
+}
+
+# Activate and generate
+
+lp_activate --no-config
+_config
+__lp_set_prompt
+
+printf 'Long prompt:\n\n  %s  \n\n' "$PS1"