<s>
IronScheme	B-Language
is	O
an	O
implementation	O
of	O
the	O
Scheme	B-Language
programming	I-Language
language	I-Language
targeting	O
the	O
Microsoft	B-Application
.NET	I-Application
Framework	I-Application
.	O
</s>
<s>
IronScheme	B-Language
is	O
a	O
complete	O
rewrite	O
of	O
IronLisp	O
,	O
incorporating	O
lessons	O
learnt	O
while	O
developing	O
IronLisp	O
.	O
</s>
<s>
IronScheme	B-Language
was	O
planning	O
to	O
build	O
upon	O
the	O
Microsoft	O
Dynamic	B-Application
Language	I-Application
Runtime	I-Application
,	O
but	O
decided	O
to	O
abandon	O
this	O
idea	O
because	O
the	O
DLR	O
branch	B-General_Concept
the	O
project	O
used	O
became	O
out	O
of	O
sync	O
with	O
the	O
trunk	B-General_Concept
,	O
and	O
also	O
because	O
the	O
DLR	O
,	O
according	O
to	O
the	O
developers	O
,	O
could	O
not	O
support	O
the	O
majority	O
of	O
the	O
Scheme	O
's	O
requirements	O
.	O
</s>
<s>
IronScheme	B-Language
eventually	O
made	O
a	O
limited	O
use	O
of	O
its	O
own	O
version	O
of	O
the	O
Microsoft	O
's	O
DLR	O
,	O
but	O
it	O
had	O
to	O
patch	O
it	O
to	O
be	O
able	O
to	O
implement	O
some	O
required	O
Scheme	O
features	O
like	O
tail	B-Language
call	I-Language
elimination	I-Language
.	O
</s>
