<s>
The	O
Polymorphic	B-Language
Programming	I-Language
Language	I-Language
(	O
PPL	B-Language
)	O
was	O
developed	O
in	O
1969	O
at	O
Harvard	O
University	O
by	O
Thomas	O
A	O
.	O
Standish	O
.	O
</s>
<s>
It	O
is	O
an	O
interactive	B-General_Concept
,	O
extensible	B-Application
language	I-Application
with	O
a	O
base	O
language	O
similar	O
to	O
the	O
language	O
APL	B-Language
.	O
</s>
<s>
The	O
assignment	O
operator	O
<	O
-	O
(	O
or	O
←	O
)	O
has	O
influenced	O
the	O
language	O
S	B-Language
.	O
</s>
