The following keywords are built into BlitzScript, and may not be used as identifiers (variables, function names, labels, etc.):

BlitzScript, EndBlitzScript, Const, Let, Label, Dim, If, Then, ElseIf, Else, EndIf, Data, Restore, Read, Lock, Unlock, Select, Case, Default, Repeat, While, And, Or, Xor, Not, For, To, Step, Next, Function, EndFunction

. Keywords are not implemented at this time.