Validation fails when script has no directives

[krystian-panek-vmltech]

Temporarily I decided to comment out all script contents, then APM reports error

for script:

# ==========================================
# Creates system users / application related
# ==========================================

# CREATE-SYSTEM-USER "service-foundation-reader" path= "/home/users/system/foundation-service"
# FOR-USER "service-foundation-reader" BEGIN
#     SET-PROPERTY "profile/givenName" "Foundation Service"
#     SET-PROPERTY "profile/familyName" "Reader"
#     SET-PROPERTY "profile/aboutMe" "Foundation service user with read access to /content"
#     ALLOW "/content" ["READ"]
#     ALLOW "/tmp" ["READ"]
#     ALLOW "/content/cq:tags" ["READ"]
#     ALLOW "/apps" ["READ"]
# END

# CREATE-SYSTEM-USER "service-foundation-writer" path= "/home/users/system/foundation-service"
# FOR-USER "service-foundation-writer" BEGIN
#     SET-PROPERTY "profile/givenName" "Foundation Service"
#     SET-PROPERTY "profile/familyName" "Writer"
#     SET-PROPERTY "profile/aboutMe" "Foundation service user with write access to /content"
#     ALLOW "/content" ["READ", "MODIFY", "CREATE", "DELETE", "REPLICATE", "READ_ACL", "MODIFY_ACL"]
#     ALLOW "/conf/straumann" ["READ", "MODIFY", "CREATE", "DELETE", "REPLICATE", "READ_ACL", "MODIFY_ACL"] --IF-EXISTS
#     ALLOW "/tmp" ["READ", "MODIFY", "CREATE", "DELETE"]
#     ALLOW "/apps" ["READ"]
#     ADD-PARENTS ["workflow-administrators"]
# END

I need to have at least

DEFINE foo "bar"

uncommented to have validation passing.
what is more APM should tell more user-friendly error when AntlR parsing error occurs like "Script has syntax error(s)." and eventually then more error details