utils/parse_directives: new automated parser for directive names.

This probably isn't perfect, but it finds all of the directives we
already had (and some new ones), so it doesn't make things worse.

diff --git a/utils/parse_directives b/utils/parse_directives
new file mode 100755 (executable)
index 0000000..5d71c6f
--- /dev/null
+++ b/utils/parse_directives
@@ -0,0 +1,63 @@
+#!/bin/sh
+
+# Parse directive names out of Nagios' xdata/xodtemplate.c.
+
+EXIT_USAGE=1
+EXIT_INPUT_FILE_DOESNT_EXIST=2
+
+posix_mktemp(){
+  # Securely create a temporary file under ${TMPDIR} using the
+  # template "tmpXXXXXX", and echo the result to stdout. This works
+  # around the absence of "mktemp" in the POSIX standard.
+  printf 'mkstemp(template)' | m4 -D template="${TMPDIR:-/tmp}/tmpXXXXXX"
+}
+
+if [ $# -lt 1 ]; then
+    echo "Usage: $0 <path-to-xodtemplate.c>"
+    exit $EXIT_USAGE
+fi
+
+
+INFILE="${1}"
+TEMPFILE="$(posix_mktemp)"
+
+if [ ! -f "$INFILE" ]; then
+    echo "Error: input file $INFILE doesn't exist."
+    exit $EXIT_INPUT_FILE_DOESNT_EXIST
+fi
+
+# The list of weekday names, taken from xdata/xodtemplate.c. The
+# Nagios strcmp parser doesn't look for them individually. Since
+# they're unlikely to change, appending them manually sounds
+# reasonable to me.
+printf '"sunday"
+"monday"
+"tuesday"
+"wednesday"
+"thursday"
+"friday"
+"saturday"
+' >> "${TEMPFILE}"
+
+# This grabs all of the variable names that are explicitly checked for
+# with strcmp in xdata/xodtemplate.c. We include these because some
+# valid variable names (e.g. "hostgroups") are implicitly mapped to
+# "real" variables whose names differ.
+#
+# The "name", "register", and "use" directives are special (literally,
+# they get the "special" font in nagios-mode.el), so we drop them from
+# the list.
+#
+# Before we parse the names, though, we move each !strcmp to its own
+# line, which greatly simplifies the parsing.
+VARCMP_REGEX='.*!strcmp(variable,[[:space:]]*"\([A-Za-z_]\{1,\}\)").*'
+sed "s/\!strcmp(/\n\!strcmp(/g" < "${INFILE}" \
+  | sed -n "s/${VARCMP_REGEX}/\"\1\"/p"       \
+  | sed '/^"name\|use\|register"$/d'          \
+  >> "${TEMPFILE}"
+
+# Finally, sort the list and print it.
+sort < "${TEMPFILE}" | uniq
+
+# ... and clean up
+rm "${TEMPFILE}"