<s>
FLOW	O
is	O
an	O
educational	B-Language
programming	I-Language
language	I-Language
designed	O
by	O
Jef	O
Raskin	O
in	O
1970	O
and	O
implemented	O
on	O
several	O
minicomputers	B-Architecture
in	O
the	O
early	O
1970s	O
.	O
</s>
<s>
The	O
overall	O
language	O
is	O
very	O
similar	O
in	O
syntax	O
and	O
structure	O
to	O
the	O
BASIC	B-Language
programming	I-Language
language	I-Language
,	O
but	O
has	O
a	O
number	O
of	O
changes	O
in	O
order	O
to	O
make	O
typing	O
code	O
easier	O
.	O
</s>
<s>
Modern	O
integrated	B-Application
development	I-Application
environments	I-Application
and	O
code-oriented	O
text	B-Application
editors	I-Application
often	O
include	O
a	O
similar	O
feature	O
,	O
now	O
normally	O
referred	O
to	O
as	O
autocomplete	O
.	O
</s>
<s>
The	O
conference	O
was	O
followed	O
by	O
a	O
training	O
session	O
that	O
ran	O
from	O
June	O
13	O
to	O
August	O
18	O
,	O
where	O
Jef	O
Raskin	O
was	O
one	O
of	O
several	O
teachers	O
involved	O
in	O
training	O
other	O
teachers	O
basic	B-Language
computer	O
skills	O
.	O
</s>
<s>
Another	O
aspect	O
of	O
the	O
FLOW	O
system	O
's	O
approach	O
to	O
user	O
interaction	O
was	O
its	O
debugger	B-Application
.	O
</s>
<s>
This	O
included	O
the	O
command	O
,	O
an	O
analog	O
to	O
BASIC	B-Language
's	O
that	O
delayed	O
after	O
executing	O
each	O
statement	O
in	O
a	O
fashion	O
similar	O
to	O
modern	O
single-step	O
systems	O
.	O
</s>
<s>
The	O
initial	O
system	O
consisted	O
of	O
three	O
Data	B-Device
General	I-Device
Nova	I-Device
minicomputers	B-Architecture
with	O
12k	O
words	O
of	O
memory	O
,	O
several	O
VST	O
1200	O
terminals	O
,	O
a	O
Tektronix	B-General_Concept
4002	I-General_Concept
graphics	O
terminal	O
,	O
and	O
an	O
HP	O
7200	O
plotter	O
.	O
</s>
<s>
The	O
first	O
version	O
of	O
FLOW	O
was	O
programmed	O
by	O
Jonathan	O
"	O
Jon	O
"	O
Collins	O
in	O
FORTRAN	B-Application
for	O
use	O
at	O
the	O
summer	O
institute	O
.	O
</s>
<s>
Flow	O
was	O
later	O
ported	O
by	O
two	O
UCSD	O
graduate	O
students	O
to	O
Nova	O
assembler	B-Language
language	I-Language
.	O
</s>
<s>
800	O
assembler	B-Language
,	O
BASIC	B-Language
and	O
Algol	B-Language
.	O
</s>
<s>
Like	O
BASIC	B-Language
,	O
FLOW	O
uses	O
line	O
numbers	O
both	O
as	O
an	O
editing	O
aid	O
as	O
well	O
as	O
statement	O
labels	O
.	O
</s>
<s>
In	O
contrast	O
to	O
BASIC	B-Language
,	O
the	O
command	O
can	O
be	O
instructed	O
to	O
stop	O
once	O
a	O
given	O
line	O
was	O
reached	O
,	O
for	O
instance	O
,	O
.	O
</s>
<s>
The	O
most	O
obvious	O
difference	O
between	O
FLOW	O
and	O
BASIC	B-Language
was	O
that	O
FLOW	O
has	O
only	O
one	O
variable	O
,	O
,	O
and	O
lacks	O
mathematical	O
operators	O
.	O
</s>
<s>
The	O
language	O
has	O
only	O
seven	O
statements	O
,	O
all	O
of	O
which	O
apply	O
basic	B-Language
logic	O
or	O
string	O
manipulation	O
.	O
</s>
<s>
There	O
is	O
no	O
equivalent	O
of	O
the	O
for	B-Language
loop	I-Language
either	O
,	O
looping	O
is	O
handled	O
entirely	O
through	O
tests	O
and	O
statements	O
.	O
</s>
<s>
The	O
language	O
does	O
not	O
have	O
direct	O
user	O
interaction	O
like	O
BASIC	B-Language
's	O
,	O
data	O
is	O
instead	O
defined	O
in	O
FLOW	O
's	O
analog	O
of	O
BASIC	B-Language
's	O
statement	O
,	O
.	O
</s>
<s>
Programs	O
can	O
contain	O
multiple	O
statements	O
,	O
but	O
unlike	O
BASIC	B-Language
's	O
where	O
all	O
of	O
the	O
lines	O
are	O
considered	O
to	O
be	O
one	O
continuous	O
block	O
of	O
data	O
,	O
only	O
one	O
statement	O
is	O
active	O
at	O
a	O
time	O
as	O
they	O
are	O
encountered	O
by	O
the	O
interpreter	O
.	O
</s>
<s>
-	O
as	O
in	O
BASIC	B-Language
,	O
takes	O
literal	O
strings	O
between	O
double	O
quotes	O
,	O
the	O
variable	O
,	O
or	O
to	O
print	O
a	O
carriage	O
return	O
.	O
</s>
