<s>
Seed7	B-Language
is	O
an	O
extensible	B-Application
general-purpose	B-Language
programming	I-Language
language	I-Language
designed	O
by	O
Thomas	O
Mertes	O
.	O
</s>
<s>
It	O
is	O
syntactically	O
similar	O
to	O
Pascal	B-Application
and	O
Ada	B-Language
.	O
</s>
<s>
Seed7	B-Language
supports	O
introducing	O
new	O
syntax	O
elements	O
and	O
their	O
semantics	O
into	O
the	O
language	O
,	O
and	O
allows	O
new	O
language	O
constructs	O
to	O
be	O
defined	O
and	O
written	O
in	O
Seed7	B-Language
.	O
</s>
<s>
The	O
implementation	O
of	O
Seed7	B-Language
differs	O
significantly	O
from	O
that	O
of	O
languages	O
with	O
hard-coded	O
syntax	O
and	O
semantics	O
.	O
</s>
<s>
Seed7	B-Language
supports	O
the	O
programming	O
paradigms	O
:	O
imperative	B-Application
,	O
object-oriented	B-Language
(	O
OO	O
)	O
,	O
and	O
generic	B-Language
.	O
</s>
<s>
It	O
also	O
supports	O
features	O
such	O
as	O
call	O
by	O
name	O
,	O
multiple	O
dispatch	O
,	O
function	B-Language
overloading	I-Language
,	O
operator	O
overloading	O
,	O
exception	B-General_Concept
handling	I-General_Concept
and	O
arbitrary-precision	B-Algorithm
arithmetic	I-Algorithm
.	O
</s>
<s>
Type	B-Language
declarations	I-Language
(	O
which	O
assign	O
a	O
name	O
to	O
a	O
type	O
)	O
and	O
function	O
definitions	O
take	O
the	O
form	O
of	O
constant	O
definitions	O
.	O
</s>
<s>
Compile-time	B-Application
expressions	O
can	O
execute	O
user-defined	O
functions	O
.	O
</s>
<s>
They	O
just	O
happen	O
at	O
different	O
times	O
:	O
compile	B-Application
time	I-Application
and	O
run	B-Library
time	I-Library
,	O
respectively	O
.	O
</s>
<s>
Functions	O
,	O
which	O
are	O
executed	O
at	O
compile	B-Application
time	I-Application
,	O
can	O
be	O
used	O
to	O
define	O
objects	O
.	O
</s>
<s>
Templates	B-Application
are	O
written	O
as	O
compile	B-Application
time	I-Application
functions	O
with	O
type	O
parameters	O
.	O
</s>
<s>
Arrays	O
,	O
hash	B-Algorithm
maps	I-Algorithm
and	O
structs	B-Language
are	O
not	O
a	O
hard-coded	O
feature	O
.	O
</s>
<s>
Instead	O
they	O
are	O
defined	O
as	O
abstract	O
data	O
type	O
in	O
libraries	B-Library
.	O
</s>
<s>
Parser	B-Language
and	O
interpreter	B-Application
are	O
part	O
of	O
the	O
runtime	B-Library
library	O
.	O
</s>
<s>
The	O
Seed7	B-Language
project	O
includes	O
both	O
an	O
interpreter	B-Application
and	O
a	O
compiler	B-Language
.	O
</s>
<s>
The	O
interpreter	B-Application
starts	O
programs	O
very	O
quickly	O
,	O
supporting	O
fast	O
program	O
development	O
.	O
</s>
<s>
The	O
compiler	B-Language
uses	O
the	O
parser	B-Language
and	O
reflection	B-Language
interfaces	O
from	O
the	O
run-time	O
library	O
to	O
generate	O
a	O
C	B-Language
program	I-Language
,	O
which	O
is	O
subsequently	O
compiled	B-Language
to	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
Compiled	B-Language
Seed7	B-Language
programs	O
can	O
have	O
comparable	O
performance	O
to	O
C	B-Language
programs	I-Language
.	O
</s>
<s>
Seed7	B-Language
has	O
many	O
libraries	B-Library
,	O
covering	O
areas	O
including	O
containers	B-Application
,	O
numeric	O
functions	O
,	O
lexical	B-Application
analysis	I-Application
,	O
file	O
manipulation	O
,	O
networking	O
(	O
sockets	B-Protocol
,	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS/SSL	B-Protocol
)	O
,	O
Hypertext	B-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
HTTP	B-Protocol
)	O
,	O
HTTP	B-Protocol
Secure	O
(	O
HTTPS	B-Protocol
)	O
,	O
File	B-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
FTP	O
)	O
,	O
Simple	B-Protocol
Mail	I-Protocol
Transfer	I-Protocol
Protocol	I-Protocol
(	O
SMTP	B-Protocol
)	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
graphics	B-Library
,	O
pixmap	O
and	O
vector	O
fonts	O
,	O
database	O
independent	O
API	O
,	O
Common	B-Language
Gateway	I-Language
Interface	I-Language
(	O
CGI	O
)	O
support	O
,	O
data	B-General_Concept
compression	I-General_Concept
,	O
archive	B-Application
files	I-Application
(	O
tar	B-Application
,	O
zip	B-General_Concept
,	O
cpio	B-Application
,	O
ar	B-Application
,	O
rpm	B-Application
)	O
,	O
character	B-General_Concept
encoding	I-General_Concept
,	O
time	O
and	O
date	O
handling	O
,	O
XML	B-Protocol
processing	O
,	O
message	B-Algorithm
digests	I-Algorithm
and	O
more	O
.	O
</s>
<s>
These	O
libraries	B-Library
reduce	O
the	O
need	O
to	O
use	O
unportable	B-Architecture
operating	B-General_Concept
system	I-General_Concept
features	O
and	O
third-party	O
libraries	B-Library
(	O
which	O
might	O
not	O
always	O
be	O
present	O
)	O
directly	O
.	O
</s>
<s>
Seed7	B-Language
libraries	B-Library
contain	O
abstraction	O
layers	O
for	O
hardware	B-Operating_System
,	O
operating	B-General_Concept
system	I-General_Concept
and	O
third-party	O
libraries	B-Library
,	O
e.g.	O
</s>
<s>
graphic	O
and	O
database	O
libraries	B-Library
.	O
</s>
<s>
In	O
other	O
words	O
,	O
no	O
changes	O
are	O
needed	O
to	O
move	O
Seed7	B-Language
programs	O
between	O
different	O
processors	B-General_Concept
or	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Seed7	B-Language
has	O
its	O
own	O
implementation	O
of	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
.	O
</s>
<s>
The	O
library	O
includes	O
AES	B-Algorithm
and	O
elliptic-curve	O
cryptography	O
.	O
</s>
<s>
Seed7	B-Language
provides	O
a	O
library	O
with	O
a	O
database	O
independent	O
API	O
.	O
</s>
<s>
Programs	O
can	O
connect	O
to	O
MySQL	B-Application
,	O
MariaDB	B-Application
,	O
SQLite	B-Language
,	O
PostgreSQL	B-Application
,	O
Oracle	B-General_Concept
,	O
Open	B-Application
Database	I-Application
Connectivity	I-Application
(	O
ODBC	B-Application
)	O
,	O
Firebird	B-Application
,	O
InterBase	B-Application
,	O
IBM	B-Application
Db2	I-Application
and	O
SQL	B-Application
Server	I-Application
databases	O
.	O
</s>
<s>
Seed7	B-Language
is	O
based	O
on	O
MASTER	O
,	O
an	O
extensible	B-Application
programming	I-Application
language	I-Application
described	O
in	O
the	O
diploma	O
and	O
doctoral	O
theses	O
of	O
Thomas	O
Mertes	O
.	O
</s>
<s>
Most	O
of	O
the	O
original	O
ideas	O
of	O
MASTER	O
,	O
such	O
as	O
user	O
defined	O
statements	O
and	O
operators	O
,	O
can	O
be	O
found	O
in	O
Seed7	B-Language
.	O
</s>
<s>
A	O
precompiler	B-Application
,	O
to	O
translate	O
MASTER	O
to	O
Pascal	B-Application
,	O
was	O
proposed	O
,	O
but	O
unimplemented	O
,	O
in	O
the	O
original	O
project	O
.	O
</s>
<s>
In	O
1989	O
,	O
development	O
began	O
on	O
an	O
interpreter	B-Application
for	O
MASTER	O
,	O
named	O
HAL	O
.	O
</s>
<s>
In	O
2005	O
,	O
the	O
MASTER	O
and	O
HAL	O
projects	O
were	O
released	O
as	O
open	B-License
source	I-License
under	O
the	O
Seed7	B-Language
project	O
name	O
.	O
</s>
<s>
As	O
of	O
version	O
2021-04-25	O
the	O
Seed7	B-Language
project	O
contains	O
more	O
than	O
500,000	O
source	O
lines	O
of	O
code	O
and	O
several	O
hundred	O
pages	O
of	O
documentation	O
.	O
</s>
<s>
An	O
extension	O
includes	O
two	O
parts	O
:	O
a	O
syntax	O
definition	O
,	O
giving	O
a	O
template	B-Application
for	O
the	O
new	O
syntactic	O
form	O
,	O
and	O
a	O
standard	O
Seed7	B-Language
function	O
,	O
used	O
to	O
define	O
the	O
semantics	O
.	O
</s>
<s>
The	O
syntax	O
definition	O
uses	O
the	O
Seed7	B-Language
Structured	B-Language
Syntax	O
Description	O
(	O
S7SSD	O
)	O
.	O
</s>
<s>
The	O
symbol	O
(	O
)	O
is	O
a	O
nonterminal	B-Algorithm
symbol	O
and	O
+	O
is	O
a	O
terminal	O
symbol	O
.	O
</s>
<s>
The	O
S7SSD	O
does	O
not	O
distinguish	O
between	O
different	O
nonterminal	B-Algorithm
symbols	I-Algorithm
.	O
</s>
<s>
Instead	O
it	O
only	O
knows	O
one	O
nonterminal	B-Algorithm
symbol	O
:	O
(	O
)	O
.	O
</s>
