<s>
In	O
computer	B-General_Concept
science	I-General_Concept
,	O
A-normal	B-Application
form	I-Application
(	O
abbreviated	O
ANF	O
,	O
sometimes	O
expanded	O
as	O
administrative	B-Application
normal	I-Application
form	I-Application
)	O
is	O
an	O
intermediate	O
representation	O
of	O
programs	O
in	O
functional	O
compilers	O
.	O
</s>
<s>
ANF	O
was	O
introduced	O
by	O
Sabry	O
and	O
Felleisen	O
in	O
1992	O
as	O
a	O
simpler	O
alternative	O
to	O
continuation-passing	B-Application
style	I-Application
(	O
CPS	O
)	O
.	O
</s>
<s>
Some	O
of	O
the	O
advantages	O
of	O
using	O
CPS	O
as	O
an	O
intermediate	O
representation	O
are	O
that	O
optimizations	O
are	O
easier	O
to	O
perform	O
on	O
programs	O
in	O
CPS	O
than	O
in	O
the	O
source	O
language	O
,	O
and	O
that	O
it	O
is	O
also	O
easier	O
for	O
compilers	O
to	O
generate	O
machine	B-Language
code	I-Language
for	O
programs	O
in	O
CPS	O
.	O
</s>
<s>
Consider	O
the	O
pure	O
λ-calculus	B-Language
with	O
weak	O
reduction	O
and	O
let-expressions	O
.	O
</s>
