<s>
Cecil	B-Language
is	O
a	O
pure	O
object-oriented	B-Language
programming	I-Language
language	I-Language
that	O
was	O
developed	O
by	O
Craig	O
Chambers	O
at	O
the	O
University	O
of	O
Washington	O
in	O
1992	O
to	O
be	O
part	O
of	O
the	O
Vortex	O
project	O
there	O
.	O
</s>
<s>
Cecil	B-Language
has	O
many	O
similarities	O
to	O
other	O
object-oriented	B-Language
languages	I-Language
,	O
most	O
notably	O
Objective-C	B-Language
,	O
Modula-3	B-Language
,	O
and	O
Self	B-Operating_System
.	O
</s>
<s>
The	O
main	O
goals	O
of	O
the	O
project	O
were	O
extensibility	B-Architecture
,	O
orthogonality	O
,	O
efficiency	O
,	O
and	O
ease-of-use	O
.	O
</s>
<s>
The	O
language	O
supports	O
multiple	O
dispatch	O
and	O
multimethods	O
,	O
dynamic	O
inheritance	B-Language
,	O
and	O
optional	O
static	O
type	O
checking	O
.	O
</s>
<s>
Unlike	O
most	O
other	O
OOP	O
systems	O
,	O
Cecil	B-Language
allows	O
subtyping	O
and	O
code	O
inheritance	B-Language
to	O
be	O
used	O
separately	O
,	O
allowing	O
run-time	O
or	O
external	O
extension	O
of	O
object	O
classes	O
or	O
instances	O
.	O
</s>
<s>
Like	O
Objective-C	B-Language
,	O
all	O
object	O
services	O
in	O
Cecil	B-Language
are	O
invoked	O
by	O
message	B-Architecture
passing	I-Architecture
,	O
and	O
the	O
language	O
supports	O
run-time	O
class	O
identification	O
.	O
</s>
<s>
These	O
features	O
allow	O
Cecil	B-Language
to	O
support	O
dynamic	O
,	O
exploratory	B-Application
programming	I-Application
styles	O
.	O
</s>
<s>
Parameterized	B-Language
types	I-Language
and	O
methods	O
(	O
generics	B-Language
,	O
polymorphism	B-Application
)	O
,	O
garbage	B-General_Concept
collection	I-General_Concept
,	O
and	O
delegation	O
are	O
also	O
supported	O
.	O
</s>
<s>
Cecil	B-Language
also	O
supports	O
a	O
module	O
mechanism	O
for	O
isolating	O
independent	O
libraries	O
or	O
packages	O
.	O
</s>
<s>
Cecil	B-Language
does	O
not	O
presently	O
support	O
threads	O
or	O
any	O
other	O
form	O
of	O
concurrency	O
.	O
</s>
<s>
A	O
standard	O
library	O
for	O
Cecil	B-Language
is	O
also	O
available	O
and	O
includes	O
various	O
collection	O
,	O
utility	O
,	O
system	O
,	O
I/O	O
,	O
and	O
GUI	O
classes	O
.	O
</s>
<s>
The	O
Diesel	O
language	O
was	O
the	O
successor	O
of	O
Cecil	B-Language
.	O
</s>
<s>
There	O
was	O
also	O
an	O
assembler	O
type	O
language	O
known	O
as	O
CESIL	B-Language
(	O
Computer	O
Education	O
in	O
Schools	O
Instructional	O
Language	O
)	O
used	O
in	O
the	O
late-1970s	O
developed	O
by	O
ICL	O
.	O
</s>
