1 files changed, 111 insertions, 0 deletions
diff --git a/research/research2.sh b/research/research2.sh
new file mode 100644
index 0000000..9908495
--- /dev/null
+++ b/research/research2.sh
@@ -0,0 +1,111 @@
+#!/bin/sh
+
+################################################################################
+# shld
+################################################################################
+__last_tu=''
+
+static()
+{
+	local arg=
+	local var=
+	local val=
+	local exp=
+
+	for arg in "${@}"; do
+		case "${arg}" in
+			*=*)
+				var="${arg%%=*}"
+				val="$(printf "${arg#*=}" | \
+					sed "s|'|'\\\\''|g")"
+				;;
+			*)
+				var="${arg}"
+				val=''
+				;;
+		esac
+		# Sanitize variable name.
+		case "${var}" in
+			[!A-Za-z_]* | *[!0-9A-Za-z_]*)
+				printf 'Syntax error: %s %s\n' \
+					'illegal static variable name:' \
+					"${var}" >&2
+				;;
+		esac
+		# Set up static variable assignments to be evaluated on scope
+		# change.
+		exp="__${__tu}_static_var_vals="
+		exp="${exp}\"\${__${__tu}_static_var_vals} ${var}='${val}'\""
+		eval "${exp}"
+		# Set up list of static variables to be cleaned up on scope
+		# change.
+		exp="__${__tu}_static_vars=\"\${__${__tu}_static_vars} ${var}\""
+		eval "${exp}"
+		# Set up static variables for current scope.
+		eval "${var}='${val}'"
+	done
+
+	# Clean up static variables from previous scope.
+	if ! [ "x${__last_tu}" = 'x' ]; then
+		eval "unset \${__${__last_tu}_static_vars}"
+	fi
+	__last_tu="${__tu}"
+}
+
+__set_up_static_vars()
+{
+	local tu="${1}"
+
+	# Clean up static variables from previous scope.
+	if ! [ "x${__last_tu}" = 'x' ]; then
+		eval "unset \${__${__last_tu}_static_vars}"
+	fi
+	__last_tu="${tu}"
+
+	# Set up static variables for specified scope.
+	eval "$(eval printf '%s' "\"$(eval printf '%s' \
+		"'\${__${tu}_static_var_vals}'")\"")"
+}
+
+################################################################################
+# TU 0
+################################################################################
+__tu='tu0'
+__tu0_locals=''
+
+static static_var0='tu0 static_var0'
+
+tu0_fn0()
+{ __set_up_static_vars 'tu0'
+	echo "tu0"
+	echo "\tstatic_var0: $static_var0"
+	echo "\tstatic_var1: $static_var1"
+}
+
+################################################################################
+# TU 1
+################################################################################
+__tu='tu1'
+__tu1_locals=''
+
+static static_var0='tu1 static_var0'
+static static_var1='tu1 static_var1'
+
+tu1_fn0()
+{ __set_up_static_vars 'tu1'
+	echo "tu1"
+	echo "\tstatic_var0: $static_var0"
+	echo "\tstatic_var1: $static_var1"
+}
+
+################################################################################
+# TU 2
+################################################################################
+main()
+{
+	tu0_fn0
+	tu1_fn0
+	tu0_fn0
+}
+
+main "${@}"