<s>
Beaujolais	B-Language
effect	I-Language
is	O
the	O
name	O
given	O
to	O
a	O
class	O
of	O
potential	O
semantic	O
errors	O
in	O
Jean	O
Ichbiah	O
's	O
draft	O
specifications	O
for	O
the	O
programming	O
language	O
Ada	B-Language
.	O
</s>
<s>
The	O
Beaujolais	B-Language
effect	I-Language
is	O
a	O
situation	O
where	O
adding	O
or	O
removing	O
a	O
single	O
use	O
clause	O
in	O
an	O
Ada	B-Language
program	O
changes	O
the	O
behavior	O
of	O
the	O
compiled	O
program	O
,	O
a	O
very	O
undesirable	O
effect	O
in	O
a	O
language	O
designed	O
for	O
semantic	O
precision	O
.	O
</s>
<s>
Ichbiah	O
took	O
steps	O
to	O
prevent	O
the	O
effect	O
when	O
he	O
updated	O
his	O
draft	O
standard	O
to	O
produce	O
the	O
final	O
Ada	B-Language
83	I-Language
language	O
standard	O
.	O
</s>
<s>
The	O
remaining	O
possible	O
situations	O
for	O
producing	O
the	O
effect	O
were	O
later	O
identified	O
by	O
mathematical	O
analysis	O
and	O
addressed	O
by	O
the	O
Ada	B-Language
95	I-Language
language	O
standard	O
,	O
making	O
any	O
situation	O
that	O
still	O
resulted	O
in	O
a	O
Beaujolais	B-Language
effect	I-Language
in	O
Ada	B-Language
83	I-Language
an	O
illegal	O
construct	O
in	O
the	O
more	O
recent	O
Ada	B-Language
95	I-Language
language	O
standard	O
.	O
</s>
<s>
In	O
principle	O
,	O
the	O
Beaujolais	B-Language
Effect	I-Language
can	O
occur	O
in	O
other	O
languages	O
that	O
use	O
namespaces	O
or	O
packages	B-Language
,	O
if	O
the	O
language	O
specification	O
does	O
not	O
ensure	O
to	O
make	O
it	O
illegal	O
.	O
</s>
<s>
The	O
Ada	B-Language
programming	I-Language
language	I-Language
allows	O
source	O
code	O
to	O
be	O
broken	O
up	O
into	O
library	O
packages	B-Language
containing	O
definitions	O
of	O
data	O
and	O
algorithms	O
that	O
can	O
be	O
used	O
by	O
programs	O
or	O
other	O
library	O
packages	B-Language
.	O
</s>
<s>
with	O
Ada.Text_IO	O
;	O
</s>
<s>
appears	O
at	O
the	O
top	O
of	O
the	O
source	O
code	O
for	O
a	O
program	O
or	O
package	O
then	O
the	O
data	O
,	O
procedures	O
,	O
and	O
functions	O
declared	O
in	O
the	O
library	O
package	O
Ada.Text_IO	O
can	O
be	O
invoked	O
within	O
that	O
source	O
code	O
.	O
</s>
<s>
This	O
is	O
the	O
implementation	O
of	O
the	O
namespace	O
concept	O
for	O
Ada	B-Language
.	O
</s>
<s>
Thus	O
a	O
program	O
that	O
has	O
the	O
with	O
Ada.Text_IO	O
;	O
directive	O
can	O
"	O
see	O
"	O
the	O
definitions	O
there	O
,	O
and	O
in	O
order	O
to	O
invoke	O
the	O
New_Line	O
procedure	O
in	O
Ada.Text_IO	O
it	O
can	O
be	O
referred	O
to	O
by	O
name	O
,	O
</s>
<s>
Ada.Text_IO.New_Line	O
;	O
</s>
<s>
and	O
similarly	O
with	O
procedures	O
or	O
functions	O
that	O
require	O
arguments	O
,	O
or	O
with	O
reads/writes	O
to	O
any	O
variables	O
declared	O
in	O
the	O
Ada.Text_IO	O
package	O
.	O
</s>
<s>
with	O
Ada.Text_IO	O
;	O
</s>
<s>
use	O
Ada.Text_IO	O
;	O
</s>
<s>
with	O
Ada.Text_IO	O
;	O
use	O
Ada.Text_IO	O
;	O
</s>
<s>
In	O
the	O
example	O
above	O
,	O
the	O
call	O
is	O
ambiguous	O
because	O
it	O
could	O
correspond	O
to	O
either	O
Ada.Text_IO.New_Line	O
or	O
A.New_Line	O
with	O
the	O
default	O
parameter	O
value	O
.	O
</s>
<s>
Ada.Text_IO.New_Line	O
;	O
</s>
