Fibonacci in Fibonacci!

gistfile1.txt

(?#Convert to Base1)
u\{0(\d*)(#*)\}/u{$1mult{##########}{$2}}/
u\{1(\d*)(#*)\}/u{$1mult{##########}{$2}#}/
u\{2(\d*)(#*)\}/u{$1mult{##########}{$2}##}/
u\{3(\d*)(#*)\}/u{$1mult{##########}{$2}###}/
u\{4(\d*)(#*)\}/u{$1mult{##########}{$2}####}/
u\{5(\d*)(#*)\}/u{$1mult{##########}{$2}#####}/
u\{6(\d*)(#*)\}/u{$1mult{##########}{$2}######}/
u\{7(\d*)(#*)\}/u{$1mult{##########}{$2}#######}/
u\{8(\d*)(#*)\}/u{$1mult{##########}{$2}########}/
u\{9(\d*)(#*)\}/u{$1mult{##########}{$2}#########}/
u\{(#*)\}/$1/

(?#Convert to base 10)
d\{((#{10})*)(\d*)\}/d{over10{$1}0$3}/
d\{((#{10})*)#(\d*)\}/d{over10{$1}1$3}/
d\{((#{10})*)##(\d*)\}/d{over10{$1}2$3}/
d\{((#{10})*)###(\d*)\}/d{over10{$1}3$3}/
d\{((#{10})*)####(\d*)\}/d{over10{$1}4$3}/
d\{((#{10})*)#####(\d*)\}/d{over10{$1}5$3}/
d\{((#{10})*)######(\d*)\}/d{over10{$1}6$3}/
d\{((#{10})*)#######(\d*)\}/d{over10{$1}7$3}/
d\{((#{10})*)########(\d*)\}/d{over10{$1}8$3}/
d\{((#{10})*)#########(\d*)\}/d{over10{$1}9$3}/
d\{over10\{\}(\d*)\}/$1/

(?#Divide by 10. Intentionally leaves a over10{} left over)
over10\{(#*)(#{10})(:(#*))?\}/over10{$1:sub{$2}{#########}$4}/
over10\{#{0,9}(:?(#+))}/$2/

(?#Multiply)
mult\{(#*)#\}\{(#*)}/mult{$1}{$2}$2
/mult\{\}\{.*?\}//

(?#Subtract)
sub\{(#*)#\}\{(#*)#\}/sub{$1}{$2}/
sub\{(#*)\}\{\}/$1/
sub\{\}\{(#*)\}/$1/

(?#Fibonacci!)
fibonacci\{(#*)#\}\{((?:#+,)*)(#+),(#+)\}/fibonacci{$1}{$2$3,$4,$3$4}/
fibonacci\{(#+)\}\{\}/fibonacci{sub{$1}{##}}{#,#}/
fibonacci\{(\d+)\}/fibonacci{u{$1}}{}/
fibonacci\{\}\{(#*,)+(#+)}/d{$2}/


(?#Code.)
fibonacci{fibonacci{7}}