<s>
FL	B-Language
(	O
short	O
for	O
"	O
Function	O
Level	O
"	O
)	O
is	O
a	O
programming	O
language	O
created	O
at	O
the	O
IBM	O
Almaden	O
Research	O
Center	O
by	O
John	O
Backus	O
,	O
John	O
Williams	O
,	O
and	O
Edward	O
Wimmers	O
in	O
the	O
1980s	O
and	O
documented	O
in	O
a	O
report	O
from	O
1989	O
.	O
</s>
<s>
FL	B-Language
was	O
designed	O
as	O
a	O
successor	O
of	O
Backus	O
 '	O
earlier	O
FP	B-Language
language	I-Language
,	O
providing	O
specific	O
support	O
for	O
what	O
Backus	O
termed	O
function-level	B-Application
programming	I-Application
.	O
</s>
<s>
FL	B-Language
is	O
a	O
dynamically	O
typed	O
strict	O
functional	B-Language
programming	I-Language
language	I-Language
with	O
throw	O
and	O
catch	O
exception	O
semantics	O
much	O
like	O
in	O
ML	B-Algorithm
.	O
</s>
<s>
Each	O
function	O
has	O
an	O
implicit	O
history	O
argument	O
which	O
is	O
used	O
for	O
doing	O
things	O
like	O
strictly	O
functional	B-Language
input/output	B-General_Concept
(	O
I/O	B-General_Concept
)	O
,	O
but	O
is	O
also	O
used	O
for	O
linking	O
to	O
C	B-Language
code	O
.	O
</s>
<s>
For	O
doing	O
optimization	O
,	O
there	O
exists	O
a	O
type-system	O
which	O
is	O
an	O
extension	O
of	O
Hindley	B-Algorithm
–	I-Algorithm
Milner	I-Algorithm
type	I-Algorithm
inference	I-Algorithm
.	O
</s>
<s>
PLaSM	B-Algorithm
is	O
a	O
"	O
geometry-oriented	O
extension	O
of	O
a	O
subset	O
of	O
the	O
FL	B-Language
language	O
"	O
first	O
described	O
in	O
1992	O
.	O
</s>
