zsh: Add _page_readme_chpwd_handler()

Open READMEs in a pager when going into a directory that contains one.

.config/zsh/zshrc.d/00-autoload.zsh

@@ -2,6 +2,8 @@ autoload -U select-word-style && select-word-style bash
 
 autoload edit-command-line; zle -N edit-command-line
 
+autoload -U add-zsh-hook
+
 (( ! $+aliases[run-help] )) || unalias run-help
 autoload -Uz run-help run-help-git zmv
 

.config/zsh/zshrc.d/40-functions.zsh

@@ -490,3 +490,18 @@ create_venv() {
 		direnv allow
 	fi
 }
+
+# Open READMEs in a pager when going into a directory that contains one.
+# See 45-hooks.zsh
+_page_readme_chpwd_handler() {
+	local readme
+	local -a readmes=(README.md README.txt README Readme.md Readme.txt Readme
+	                  readme.md readme.txt readme)
+
+	for readme in "$readmes[@]"; do
+		[[ -e "$readme" ]] || continue
+
+		${PAGER:-less} "$readme"
+		break
+	done
+}

.config/zsh/zshrc.d/45-hooks.zsh

@@ -0,0 +1,4 @@
+# vim: ft=zsh
+
+(( ! $+function[_page_readme_chpwd_handler] )) \
+	|| add-zsh-hook chpwd _page_readme_chpwd_handler