1 files changed, 106 insertions, 0 deletions
diff --git a/nncmpp.actions.awk b/nncmpp.actions.awk
new file mode 100644
index 0000000..b4d7eaf
--- /dev/null
+++ b/nncmpp.actions.awk
@@ -0,0 +1,106 @@
+# nncmpp.actions.awk: produce C code for a list of user actions
+#
+# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
+# SPDX-License-Identifier: 0BSD
+#
+# Usage: env LC_ALL=C A=0 B=1 awk -f nncmpp.actions.awk \
+#  nncmpp.actions > nncmpp-actions.h
+
+# --- Preprocessor -------------------------------------------------------------
+
+function fatal(message) {
+	print "// " FILENAME ":" FNR ": fatal error: " message
+	print FILENAME ":" FNR ": fatal error: " message > "/dev/stderr"
+	exit 1
+}
+
+function condition(pass,    passing, a, i) {
+	split(substr($0, RSTART + RLENGTH), a, /[[:space:]]+/)
+	if (!(1 in a))
+		fatal("missing condition")
+
+	passing = 0
+	for (i in a)
+		if (a[i] && !pass == !ENVIRON[a[i]])
+			passing = 1
+
+	while (getline > 0) {
+		if (match($0, /^[[:space:]]*[.]endif[[:space:]]*$/))
+			return 1
+
+		if (match($0, /^[[:space:]]*[.]else[[:space:]]*$/))
+			passing = !passing
+		else if (!directive() && passing)
+			process()
+	}
+
+	fatal("unterminated condition body")
+}
+
+# Multiple arguments mean logical OR, multiple directives mean logical AND.
+# Similar syntax is also used by Exim, BSD make, or various assemblers.
+#
+# Looking at what others have picked for their preprocessor syntax:
+# {OpenGL, FreeBASIC} reuse #ifdef, which would be confusing with C code around,
+# {Mental Ray, RapidQ and UniVerse BASIC} use $ifdef, NSIS has !ifdef,
+# and Verilog went for `ifdef.  Not much more can be easily found.
+function directive() {
+	sub(/#.*/, "")
+	if (match($0, /^[[:space:]]*[.]ifdef[[:space:]]+/))
+		return condition(1)
+	if (match($0, /^[[:space:]]*[.]ifndef[[:space:]]+/))
+		return condition(0)
+	if (/^[[:space:]]*[.]/)
+		fatal("unexpected or unsupported directive")
+	return 0
+}
+
+!directive() {
+	process()
+}
+
+# --- Postprocessor ------------------------------------------------------------
+
+function strip(string) {
+	gsub(/^[[:space:]]*|[[:space:]]*$/, "", string)
+	return string
+}
+
+function process(    constant, name, description) {
+	if (match($0, /,/)) {
+		constant = name = strip(substr($0, 1, RSTART - 1))
+		description = strip(substr($0, RSTART + RLENGTH))
+		gsub(/_/, "-", name)
+
+		N++
+		Constants[N] = constant
+		Names[N] = tolower(name)
+		Descriptions[N] = description
+	} else if (/[^[:space:]]/) {
+		fatal("invalid action definition syntax")
+	}
+}
+
+function tocstring(string) {
+	gsub(/\\/, "\\\\", string)
+	gsub(/"/, "\\\"", string)
+	return "\"" string "\""
+}
+
+END {
+	print "enum action {"
+	for (i in Constants)
+		print "\t" "ACTION_" Constants[i] ","
+	print "\t" "ACTION_COUNT"
+	print "};"
+	print ""
+	print "static const char *g_action_names[] = {"
+	for (i in Names)
+		print "\t" tocstring(Names[i]) ","
+	print "};"
+	print ""
+	print "static const char *g_action_descriptions[] = {"
+	for (i in Descriptions)
+		print "\t" tocstring(Descriptions[i]) ","
+	print "};"
+}