fix: Fix module stuff

src/lib.sh

@@ -1,10 +1,10 @@
 std::bootstrap() {
-	[ -n "${STD_VERSION:-}" ] &&
-		std::panic "\`std\` ($STD_VERSION) already loaded, can\'t load version $1"
+	[ -n "${STD_VERSION:-}" ] && [ "${STD_VERSION:-}" != "$1" ] &&
+		std::panic "\`std\` ($STD_VERSION) already loaded, can't load version $1"
 
 	declare -g STD_VERSION=$1
 }
-std::bootstrap 0.1.3
+std::bootstrap 0.2.0
 
 INTERPRETER=$(ps -p $$ | awk '$1 != "PID" {print $(NF)}')
 : "${INTERPRETER:=bash}"
@@ -52,46 +52,64 @@ std::sensible() {
 	esac
 }
 
+# shellcheck disable=SC2016
 std::mod::get-self-path() {
 	local interpreter
 	interpreter=$(std::interpreter::name)
 	case $interpreter in
 	bash)
-		realpath -e "$(dirname "${BASH_SOURCE[0]}")"
+		echo 'realpath -e "$(dirname "${BASH_SOURCE[0]}")"'
 		;;
 	zsh)
-		eval 'realpath -e "$(dirname "${(%):-%x}")"'
+		echo 'realpath -e "$(dirname "${(%):-%x}")"'
 		;;
 	ksh)
 		# untested, nevermind, ksh doesn't even support functions with :: in them
-		eval 'realpath -e "$(dirname "${.sh.file}")"'
+		echo 'realpath -e "$(dirname "${.sh.file}")"'
 		;;
 	*)
-		echo "Not sure how to get sourced path for $interpreter" >&2
-		exit 1
+		echo '
+			echo "Not sure how to get sourced path for $interpreter" >&2
+			exit 1
+		'
 		;;
 	esac
 }
 
+## Backtrace alternative to `${FOO?Msg}`
+std::unwrap() {
+	if [ -z "$1" ]; then
+		std::panic "$2"
+	fi
+
+	echo "$1"
+}
+
+##
+# Should be called like:
+#
+# `std::mod::init mylib 0.1.0 "$(eval "$(std::mod::get-self-path)")"` in a file
+# immediately within `src/`
+##
 declare -A std__module_versions
 declare -A std__module_paths
 std::mod::init() {
-	local module_name=${1?Expected a module name}
-	local module_version=${2?Expected a module version}
+	local module_name module_version module_path
+	module_name=$(std::unwrap "${1:-}" "Expected a module name")
+	module_version=$(std::unwrap "${2:-}" "Expected a module version")
+	module_path=$(std::unwrap "${3:-}" "Expected a module path")
 
-	local modpath
-	modpath=$(std::mod::get-self-path)
-
-	if [ -n "${std__module_versions[$module_name]:-}" ]; then
+	if [ -n "${std__module_versions[$module_name]:-}" ] && [ "${std__module_versions[$module_name]:-}" != "$module_version" ]; then
 		std::panic "$module_name (${std__module_versions[$module_name]}) already initialized" \
-			"from $modpath, when ${std__module_paths[$module_name]} existed"
+			$'\n'"  from $module_path ($module_version), when ${std__module_paths[$module_name]} existed"
 	fi
 
 	std__module_versions[$module_name]=$module_version
-	std__module_paths[$module_name]=$modpath
+	std__module_paths[$module_name]=$module_path
 }
 
-std::mod::init std "$STD_VERSION"
+std::mod::init std "$STD_VERSION" \
+	"$(eval "$(std::mod::get-self-path)")"
 
 std::mod::get-path() {
 	local module_name=${1?Expected a module name}