fa_for_identifiers.in

# this FA describes identifiers of the form [A-Za-z_][A-Za-z0-9_]*

# set of states
Init Invalid Valid

# initial state
Init

# set of final states
Valid

# alphabet
_ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890

# the set of transitions
# each state is followed by a list of pairs, where each pair is a list of symbols and the state to which they lead
# the transitions for a state can be described on separate lines
Init 1234567890 Invalid _ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz Valid
Invalid _ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890 Invalid
Valid _ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890 Valid