<s>
Epigram	B-Language
is	O
a	O
functional	B-Language
programming	I-Language
language	I-Language
with	O
dependent	O
types	O
,	O
and	O
the	O
integrated	B-Application
development	I-Application
environment	I-Application
(	O
IDE	O
)	O
usually	O
packaged	O
with	O
the	O
language	O
.	O
</s>
<s>
Epigram	B-Language
's	O
type	O
system	O
is	O
strong	O
enough	O
to	O
express	O
program	B-Application
specifications	I-Application
.	O
</s>
<s>
The	O
goal	O
is	O
to	O
support	O
a	O
smooth	O
transition	O
from	O
ordinary	O
programming	O
to	O
integrated	O
programs	O
and	O
proofs	O
whose	O
correctness	O
can	O
be	O
checked	O
and	O
certified	O
by	O
the	O
compiler	B-Language
.	O
</s>
<s>
Epigram	B-Language
exploits	O
the	O
Curry	O
–	O
Howard	O
correspondence	O
,	O
also	O
termed	O
the	O
propositions	O
as	O
types	O
principle	O
,	O
and	O
is	O
based	O
on	O
intuitionistic	O
type	O
theory	O
.	O
</s>
<s>
The	O
Epigram	B-Language
prototype	O
was	O
implemented	O
by	O
Conor	O
McBride	O
based	O
on	O
joint	O
work	O
with	O
James	O
McKinna	O
.	O
</s>
<s>
Its	O
development	O
is	O
continued	O
by	O
the	O
Epigram	B-Language
group	O
in	O
Nottingham	O
,	O
Durham	O
,	O
St	O
Andrews	O
,	O
and	O
Royal	O
Holloway	O
,	O
University	O
of	O
London	O
in	O
the	O
United	O
Kingdom	O
(	O
UK	O
)	O
.	O
</s>
<s>
The	O
current	O
experimental	O
implementation	O
of	O
the	O
Epigram	B-Language
system	O
is	O
freely	O
available	O
together	O
with	O
a	O
user	O
manual	O
,	O
a	O
tutorial	O
and	O
some	O
background	O
material	O
.	O
</s>
<s>
The	O
system	O
has	O
been	O
used	O
under	O
Linux	B-Application
,	O
Windows	B-Application
,	O
and	O
macOS	B-Application
.	O
</s>
<s>
It	O
is	O
currently	O
unmaintained	O
,	O
and	O
version	O
2	O
,	O
which	O
was	O
intended	O
to	O
implement	O
Observational	O
Type	O
Theory	O
,	O
was	O
never	O
officially	O
released	O
but	O
exists	O
in	O
GitHub	B-Application
.	O
</s>
<s>
Epigram	B-Language
uses	O
a	O
two-dimensional	O
,	O
natural	O
deduction	O
style	O
syntax	O
,	O
with	O
versions	O
in	O
LaTeX	B-Application
and	O
ASCII	B-Protocol
.	O
</s>
<s>
Here	O
are	O
some	O
examples	O
from	O
The	O
Epigram	B-Language
Tutorial	O
:	O
</s>
<s>
This	O
is	O
equivalent	O
to	O
the	O
Haskell	B-Language
declaration	O
"	O
data	O
Nat	O
=	O
Zero	O
|	O
Suc	O
Nat	O
"	O
.	O
</s>
<s>
In	O
LaTeX	B-Application
,	O
the	O
code	O
is	O
displayed	O
as	O
:	O
</s>
<s>
And	O
...	O
in	O
ASCII	B-Protocol
:	O
</s>
<s>
And	O
...	O
in	O
ASCII	B-Protocol
:	O
</s>
<s>
Epigram	B-Language
is	O
essentially	O
a	O
typed	O
lambda	O
calculus	O
with	O
generalized	B-Application
algebraic	I-Application
data	I-Application
type	I-Application
extensions	O
,	O
except	O
for	O
two	O
extensions	O
.	O
</s>
<s>
Full	O
dependent	O
types	O
,	O
as	O
implemented	O
in	O
Epigram	B-Language
,	O
are	O
a	O
powerful	O
abstraction	O
.	O
</s>
<s>
(	O
Unlike	O
in	O
Dependent	B-Language
ML	I-Language
,	O
the	O
value(s )	O
depended	O
upon	O
may	O
be	O
of	O
any	O
valid	O
type	O
.	O
)	O
</s>
<s>
A	O
sample	O
of	O
the	O
new	O
formal	B-Application
specification	I-Application
capabilities	O
dependent	O
types	O
bring	O
may	O
be	O
found	O
in	O
The	O
Epigram	B-Language
Tutorial	O
.	O
</s>
