zsh: history: add improved history search functionality

zsh/history.zsh

@@ -2,3 +2,28 @@
 HISTSIZE=1000000
 SAVEHIST=1000000
 HISTFILE=~/.zsh/zsh_history
+
+# ===== functions
+# vim-like completion of previous executed commands. Depending on cursor
+# position it either behaves like cursor up/down or includes already typed
+# text.
+zle -N zshrc-vi-history-beginning-search-backward
+zshrc-vi-history-beginning-search-backward()
+{
+	local not_at_beginning_of_line
+	if [[ $CURSOR -ne 0 ]]; then
+		not_at_beginning_of_line=yes
+	fi
+
+	zle history-beginning-search-backward
+
+	# start Vi-mode and stay at the same position (Vi-mode moves one left,
+	# this counters it).
+	zle vi-cmd-mode
+	if [[ -n $not_at_beginning_of_line ]]; then
+		zle vi-forward-char
+	fi
+}
+
+# only ^P bind is necessary as ^P enters Vi-Mode and ^N only makes sense after calling ^P
+bindkey '^P' zshrc-vi-history-beginning-search-backward