<s>
The	O
Production	B-Application
Quality	I-Application
Compiler-Compiler	I-Application
Project	I-Application
(	O
or	O
PQCC	B-Application
)	O
was	O
a	O
long-term	O
project	O
led	O
by	O
William	O
Wulf	O
at	O
Carnegie	O
Mellon	O
University	O
to	O
produce	O
an	O
industrial-strength	O
compiler-compiler	B-Language
.	O
</s>
<s>
PQCC	B-Application
would	O
produce	O
full	O
,	O
optimizing	O
programming	B-Language
language	I-Language
compilers	I-Language
from	O
descriptions	O
of	O
the	O
programming	O
language	O
and	O
the	O
target	O
machine	O
.	O
</s>
<s>
Though	O
the	O
goal	O
of	O
a	O
fully	O
automatic	O
process	O
was	O
not	O
realized	O
,	O
PQCC	B-Application
technology	O
and	O
ideas	O
were	O
the	O
basis	O
of	O
production	O
compilers	B-Language
from	O
Intermetrics	O
,	O
Tartan	O
Laboratories	O
,	O
and	O
others	O
.	O
</s>
<s>
The	O
focus	O
of	O
the	O
project	O
was	O
on	O
the	O
semantics	B-Application
and	O
machine-dependent	B-Architecture
phases	O
of	O
compilation	B-Language
,	O
since	O
lexical	B-Application
and	O
syntactic	B-Language
analysis	I-Language
were	O
already	O
well	O
understood	O
.	O
</s>
<s>
The	O
automatic	O
construction	O
of	O
the	O
compiler	B-Language
then	O
consists	O
of	O
deriving	O
these	O
tables	O
from	O
the	O
semantic	O
definitions	O
of	O
the	O
language	O
and	O
target	O
machine	O
.	O
</s>
<s>
Though	O
this	O
approach	O
was	O
largely	O
successful	O
for	O
target	O
machine	O
description	O
,	O
it	O
was	O
less	O
so	O
for	O
semantics	B-Application
.	O
</s>
