nncmpp/nncmpp.actions.awk

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# 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 "};"
}