Fix path trimming and line break

pure.zsh

@@ -120,46 +120,13 @@ prompt_pure_preprompt_render() {
 	# Initialize the preprompt array.
 	local -a preprompt_parts
 
-	# Trim prompt dirs
-	# adapted from https://github.com/agkozak/agkozak-zsh-prompt/blob/ee704a226e74246d1d03c1b7658963f87cc3b1c1/agkozak-zsh-prompt.plugin.zsh#L154
-	# TODO: This is so ugly... maybe profile it
-	# TODO: This sets prompt length wrong!
-	# TODO: Also: /usr/.../dir instead or /../subdir/dir
-	typeset -g DIRMAXTRIM=${PURE_DIRMAXTRIM:-2}
-	_trim_dir() {
-		local dir dir_count
-		case $HOME in
-			/) dir=${PWD} ;;
-			*) dir=${PWD#$HOME} ;;
-		esac
-		# The number of directory elements is the number of slashes in ${PWD#$HOME}
-		dir_count=$((${#dir} - ${#${dir//\//}}))
-		if (( dir_count <= $DIRMAXTRIM )); then
-			case $PWD in
-				${HOME}) printf '%s' '~' ;;
-				${HOME}*) printf '~%s' "${dir}" ;;
-				*) print -n "$PWD" ;;
-			esac
-		else
-			local lopped_path i
-			lopped_path=${dir}
-			i=0
-			while (( i != $DIRMAXTRIM )); do
-				lopped_path=${lopped_path%\/*}
-				(( i++ ))
-			done
-			case $PWD in
-				${HOME}*) printf '~/...%s' "${dir#${lopped_path}}" ;;
-				*) printf '...%s' "${PWD#${lopped_path}}" ;;
-			esac
-		fi
-	}
-
 	# Set the path.
-	#preprompt_parts+=('%F{black}%K{white} %~ %f%k')
-	# %...{} is a prompt escape sequence.
-	# _trim_dir() will be executed at render time
-	preprompt_parts+=('%F{black}%K{white} %{$(_trim_dir)%} %f%k')
+	# Trim is done via %(cond|if true|if false), %-DIGIT~ selects path components
+	# See https://rockhopper.dk/linux/zsh-promptwindow-title-trim-middle-of-path/
+	# and https://unix.stackexchange.com/questions/273529/shorten-path-in-zsh-prompt
+	# and http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html
+	# and https://github.com/wesbos/Cobalt2-iterm/issues/15
+	preprompt_parts+=('%F{black}%K{white}%  %(5~|%-1~/…/%3~|%4~) %f%k')
 
 	# Add git branch and dirty status info.
 	typeset -gA prompt_pure_vcs_info
@@ -183,29 +150,27 @@ prompt_pure_preprompt_render() {
 		# removes the preprompt and only the original PROMPT remains.
 		cleaned_ps1=${PROMPT##*${prompt_newline}}
 	fi
+	local prompt_space='%-666v '
+	if [[ $PROMPT = *$prompt_space* ]]; then
+		cleaned_ps1=${PROMPT##*${prompt_space}}
+	fi
 	unset MATCH MBEGIN MEND
 
-	typeset -g expanded_prompt_pre=''
-	expanded_prompt_pre=${(j..)preprompt_parts}
-	#expanded_prompt_pre+=('%F{black}%K{white} %~ %f%k')
+	local expanded_prompt_pre
+    expanded_prompt_pre="${(j. .)preprompt_parts}"
 	expanded_prompt_pre="${(S%%)expanded_prompt_pre}"
-	# Length is 20 chars more than actual path string
-	# needs to be inside single [] brackets and as quoted string
-	# TODO: actually fix this and set prompt_newline before cleaned_ps1
-	# else zsh gets the wrong width for the prompt and messes up
-	if [ "${#expanded_prompt_pre}" -lt 45 ]; then
-		# Newline/no newline are swapped
-		prompt_newline='%666v ' # insert space before virtualenv etc.
-	else
-		prompt_newline=$'\n%{\r%}'
-	fi
-
+    local prompt_space_or_newline
+    if [ "${#expanded_prompt_pre}" -gt "30" ]; then
+        prompt_space_or_newline=$prompt_newline
+    else
+        prompt_space_or_newline=$prompt_space
+    fi
 
 	# Construct the new prompt with a clean preprompt.
 	local -ah ps1
 	ps1=(
 		${(j. .)preprompt_parts}  # Join parts, space separated.
-		$prompt_newline           # Separate preprompt and prompt.
+		$prompt_space_or_newline  # Separate preprompt and prompt.
 		$cleaned_ps1
 	)
 
@@ -232,7 +197,7 @@ prompt_pure_precmd() {
 	unset prompt_pure_cmd_timestamp
 
 	# shows the full path in the title
-	prompt_pure_set_title 'expand-prompt' '%~'
+	prompt_pure_set_title 'expand-prompt' '%(4~|%-1~/…/%2~|%3~)'
 
 	# preform async git dirty check and fetch
 	prompt_pure_async_tasks
@@ -615,7 +580,7 @@ prompt_pure_setup() {
 
 	if [[ -z $prompt_newline ]]; then
 		# This variable needs to be set, usually set by promptinit.
-		typeset -g prompt_newline='%666v '
+		typeset -g prompt_newline=$'\n%{\r%}'
 	fi
 
 	zmodload zsh/datetime
@@ -680,4 +645,4 @@ prompt_pure_setup() {
 }
 
 prompt_pure_setup "$@"
-# vim: noet sw=8
+# vim: noet sw=4