From 23c04846378d7861a1afa6edeaa94f6d151bbb53 Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pj@pehjota.net>
Date: Tue, 23 Feb 2016 14:00:21 -0500
Subject: Old runtime library research scripts: Now you see them...

Modification dates:

    research1.sh: 2016-02-13 14:44:30 -0500
    research2.sh: 2016-02-13 19:25:25 -0500
    research3.sh: 2016-02-14 17:56:33 -0500
    research4.sh: 2016-02-23 01:26:54 -0500
---
(limited to 'research/research3.sh')

diff --git a/research/research3.sh b/research/research3.sh
new file mode 100644
index 0000000..ad994fa
--- /dev/null
+++ b/research/research3.sh
@@ -0,0 +1,157 @@
+#!/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 and functions from previous scope.
+	if ! [ "x${__last_tu}" = 'x' ]; then
+		eval "unset \${__${__last_tu}_static_vars}"
+		for fn in $(eval printf '%s' \
+				"\"\${__${__last_tu}_static_fns}\""); do
+			unset -f "${fn%:*}"
+		done
+	fi
+	__last_tu="${tu}"
+
+	# Set up static variables and functions for specified scope.
+	eval "$(eval printf '%s' "\"$(eval printf '%s' \
+		"'\${__${tu}_static_var_vals}'")\"")"
+	for fn in $(eval printf '%s' "\"\${__${tu}_static_fns}\""); do
+		eval "${fn%:*}() { ${fn#*:}; }"
+	done
+}
+
+################################################################################
+# TU 0
+################################################################################
+__tu='tu0'
+__tu0_static_vars=''
+__tu0_static_fns=''
+
+entry0()
+{ __set_up_static_vars 'tu0'
+	echo "tu0 entry0()"
+	foo
+}
+
+call0()
+{
+	${1}
+}
+
+# shpp will convert:
+# static foo()
+# into:
+__tu0_static_fns="${__tu0_static_fns} foo:__tu0_fn0"
+static foo=__tu0_fn0
+__tu0_fn0()
+{ __set_up_static_vars 'tu0'
+	echo "tu0 foo()"
+	bar
+}
+
+# bar()
+__tu0_static_fns="${__tu0_static_fns} bar:__tu0_fn1"
+static bar=__tu0_fn1
+__tu0_fn1()
+{ __set_up_static_vars 'tu0'
+	echo "tu0 bar()"
+}
+
+################################################################################
+# TU 1
+################################################################################
+__tu='tu1'
+__tu1_static_vars=''
+__tu1_static_fns=''
+
+entry1()
+{ __set_up_static_vars 'tu1'
+	echo "tu1 entry1()"
+	foo
+}
+
+# foo()
+__tu1_static_fns="${__tu1_static_fns} foo:__tu1_fn0"
+static foo=__tu1_fn0
+__tu1_fn0()
+{ __set_up_static_vars 'tu1'
+	echo "tu1 foo()"
+	call0 ${baz}
+}
+
+# baz()
+__tu1_static_fns="${__tu1_static_fns} baz:__tu1_fn1"
+static baz=__tu1_fn1
+__tu1_fn1()
+{ __set_up_static_vars 'tu1'
+	echo "tu1 baz()"
+}
+
+################################################################################
+# TU 2
+################################################################################
+__tu='tu2'
+__tu2_static_vars=''
+__tu2_static_fns=''
+
+main()
+{ __set_up_static_vars 'tu2'
+	entry0
+	entry1
+}
+
+main "${@}"
--
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