<s>
GNU	B-Application
TeXmacs	I-Application
is	O
a	O
scientific	O
word	B-General_Concept
processor	I-General_Concept
and	O
typesetting	O
component	O
of	O
the	B-Application
GNU	I-Application
Project	I-Application
.	O
</s>
<s>
It	O
originated	O
as	O
a	O
variant	O
of	O
GNU	B-Application
Emacs	I-Application
with	O
TeX	B-Application
functionalities	O
,	O
though	O
it	O
shares	O
no	O
code	O
with	O
those	O
programs	O
,	O
while	O
using	O
TeX	B-Application
fonts	O
.	O
</s>
<s>
The	O
program	O
produces	O
structured	O
documents	O
with	O
a	O
WYSIWYG	B-Application
user	B-Application
interface	I-Application
.	O
</s>
<s>
The	O
editor	O
provides	O
high-quality	O
typesetting	O
algorithms	O
and	O
TeX	B-Application
and	O
other	O
fonts	O
for	O
publishing	O
professional	O
looking	O
documents	O
.	O
</s>
<s>
As	O
a	O
structured	O
WYSIWYG	B-Application
editor	I-Application
and	O
document	B-General_Concept
preparation	I-General_Concept
system	O
,	O
TeXmacs	B-Application
is	O
similar	O
to	O
earlier	O
structured	O
document	B-General_Concept
editors	I-General_Concept
,	O
such	O
as	O
Interleaf	O
(	O
first	O
release	O
1985	O
)	O
,	O
Framemaker	B-Device
(	O
1986	O
)	O
,	O
SoftQuad	O
Author/Editor	O
(	O
1988	O
)	O
,	O
Lilac	O
,	O
(	O
1991	O
)	O
,	O
and	O
Thot	O
;	O
there	O
was	O
also	O
academic	O
research	O
into	O
interactive	O
editing	O
of	O
complex	O
typographical	O
constructs	O
represented	O
logically	O
.	O
</s>
<s>
In	O
the	O
2000s	O
and	O
2010s	O
,	O
interest	O
on	O
interactive	O
editing	O
of	O
structured	O
text	O
encouraged	O
the	O
development	O
of	O
programs	O
intended	O
for	O
scholars	O
in	O
the	O
humanities	O
;	O
an	O
example	O
of	O
this	O
is	O
CWRC-Writer	O
,	O
a	O
visual	O
XML	B-Protocol
editor	O
with	O
"	O
Close-to-WYSIWYG	O
editing	O
and	O
enrichment	O
of	O
scholarly	O
texts	O
with	O
meaningful	O
visual	O
representations	O
of	O
markup	O
"	O
.	O
</s>
<s>
On	O
another	O
side	O
of	O
the	O
editing	O
and	O
document	B-General_Concept
preparation	I-General_Concept
world	O
,	O
a	O
program	O
for	O
visual	O
interaction	O
with	O
structured	O
texts	O
written	O
in	O
LaTeX	B-Application
is	O
LyX	B-Language
,	O
which	O
does	O
not	O
aim	O
at	O
WYSIWYG	B-Application
editing	O
but	O
at	O
visual	O
representation	O
of	O
the	O
structure	O
(	O
WYSIWYM	B-General_Concept
)	O
.	O
</s>
<s>
Like	O
in	O
many	O
WYSIWYG	B-Application
editors	I-Application
(	O
such	O
as	O
Microsoft	B-Application
Word	I-Application
)	O
,	O
authors	O
manipulate	O
a	O
document	O
on	O
screen	O
which	O
should	O
print	O
to	O
a	O
similar-looking	O
paper	O
copy	O
.	O
</s>
<s>
The	O
goal	O
of	O
TeXmacs	B-Application
is	O
to	O
provide	O
a	O
WYSIWYG	B-Application
editor	I-Application
that	O
nevertheless	O
makes	O
it	O
possible	O
to	O
write	O
correctly	O
structured	O
documents	O
with	O
aesthetically	O
pleasing	O
typesetting	O
results	O
.	O
</s>
<s>
TeXmacs	B-Application
is	O
a	O
front-end	O
to	O
LaTeX	B-Application
but	O
TeXmacs	B-Application
documents	O
can	O
be	O
converted	O
to	O
either	O
TeX	B-Application
or	O
LaTeX	B-Application
.	O
</s>
<s>
LaTeX	B-Application
also	O
can	O
be	O
imported	O
(	O
to	O
some	O
extent	O
)	O
,	O
and	O
both	O
import	O
from	O
and	O
export	O
to	O
HTML	B-Language
,	O
Scheme	B-Language
,	O
Verbatim	O
,	O
and	O
XML	B-Protocol
is	O
provided	O
;	O
the	O
HTML	B-Language
export	O
is	O
stylable	O
with	O
CSS	O
(	O
since	O
version	O
1.99.14	O
)	O
.	O
</s>
<s>
There	O
is	O
a	O
converter	O
for	O
MathML	B-Language
as	O
well	O
,	O
and	O
TeXmacs	B-Application
can	O
output	O
PDF	B-Application
and	O
PostScript	B-Language
for	O
printing	O
.	O
</s>
<s>
TeXmacs	B-Application
can	O
handle	O
mathematical	O
formulas	O
,	O
tables	O
,	O
images	O
,	O
cross-references	O
and	O
citations	O
.	O
</s>
<s>
It	O
can	O
be	O
used	O
as	O
a	O
front-end	O
to	O
a	O
number	O
of	O
computer	B-General_Concept
algebra	I-General_Concept
systems	I-General_Concept
such	O
as	O
Maxima	B-Language
,	O
FriCAS	B-Language
and	O
SageMath	B-Application
,	O
and	O
can	O
in	O
turn	O
integrate	O
some	O
of	O
their	O
output	O
into	O
its	O
typesetting	O
.	O
</s>
<s>
TeXmacs	B-Application
also	O
supports	O
a	O
Scheme	B-Language
extension	O
language	O
called	O
Guile	B-Application
for	O
customizing	O
the	O
program	O
and	O
writing	O
extensions	O
.	O
</s>
<s>
It	O
also	O
features	O
a	O
presentation	B-Application
mode	O
and	O
a	O
small	O
technical	B-Application
drawing	I-Application
editor	O
and	O
there	O
are	O
plans	O
to	O
evolve	O
towards	O
a	O
complete	O
scientific	O
office	O
suite	O
with	O
spreadsheet	B-Application
capabilities	O
.	O
</s>
<s>
An	O
implementation	O
of	O
spreadsheets	B-Application
is	O
present	O
starting	O
from	O
version	O
1.99.12	O
;	O
spreadsheets	B-Application
in	O
TeXmacs	B-Application
can	O
take	O
advantage	O
of	O
plugins	O
(	O
for	O
example	O
Python	B-Language
or	O
Maxima	B-Language
)	O
to	O
compute	O
cell	O
values	O
.	O
</s>
<s>
TeXmacs	B-Application
currently	O
runs	O
on	O
most	O
Unix-based	O
architectures	O
including	O
Linux	B-Application
,	O
FreeBSD	B-Operating_System
,	O
Cygwin	B-Language
,	O
Haiku	B-Language
and	O
macOS	B-Application
.	O
</s>
<s>
Along	O
with	O
the	O
Cygwin	B-Language
version	O
,	O
a	O
native	O
port	O
is	O
available	O
for	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
In	O
the	O
TeXmacs	B-Application
editor	O
structure	O
and	O
appearance	O
of	O
the	O
document	O
are	O
represented	O
at	O
the	O
same	O
time	O
;	O
the	O
structure	O
is	O
made	O
evident	O
to	O
the	O
user	O
by	O
surrounding	O
logical	O
units	O
of	O
the	O
document	O
in	O
nested	O
focus	O
frames	O
carrying	O
color	O
cues	O
that	O
are	O
displayed	O
according	O
to	O
the	O
movement	O
of	O
the	O
cursor	O
.	O
</s>
<s>
In	O
the	O
editor	O
it	O
is	O
possible	O
to	O
switch	O
between	O
text	O
mode	O
and	O
source	O
mode	O
editing	O
,	O
and	O
support	O
for	O
the	O
composition	O
of	O
macros	O
is	O
present	O
;	O
the	O
source	O
editor	O
is	O
syntax-aware	B-Application
.	O
</s>
<s>
TeXmacs	B-Application
facilitates	O
the	O
inputting	O
of	O
mathematical	O
formulas	O
by	O
mapping	O
sequences	O
of	O
keyboard	O
presses	O
to	O
symbols	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
use	O
TeXmacs	B-Application
as	O
a	O
batch	B-General_Concept
processor	I-General_Concept
(	O
which	O
is	O
LaTeX	B-Application
's	O
usual	O
operation	O
mode	O
)	O
,	O
using	O
X	B-Device
virtual	I-Device
framebuffer	I-Device
to	O
avoid	O
opening	O
unwanted	O
windows	O
while	O
processing	O
.	O
</s>
<s>
generates	O
a	O
PDF	B-Application
file	I-Application
"	O
article.pdf	O
"	O
from	O
a	O
TeXmacs	B-Application
document	O
"	O
article.tm	O
 "	O
.	O
</s>
<s>
All	O
TeXmacs	B-Application
documents	O
or	O
document	O
fragments	O
can	O
be	O
thought	O
of	O
as	O
trees	O
(	O
the	O
concept	O
of	O
tree	O
exists	O
as	O
well	O
in	O
the	O
SGML	B-Language
markup	O
language	O
,	O
to	O
which	O
the	O
Texmacs	B-Application
format	O
is	O
similar	O
)	O
.	O
</s>
<s>
(	O
written	O
here	O
with	O
the	O
TeX	B-Application
markup	I-Application
used	O
by	O
Wikipedia	O
)	O
and	O
is	O
turned	O
by	O
TeXmacs	B-Application
 '	O
own	O
typesetting	O
engine	O
into	O
a	O
typeset	O
formula	O
,	O
here	O
inserted	O
as	O
an	O
image	O
:	O
</s>
<s>
TeXmacs	B-Application
trees	O
are	O
represented	O
in	O
TeXmacs	B-Application
files	O
as	O
strings	O
,	O
and	O
in	O
the	O
TeXmacs	B-Application
editor	O
as	O
the	O
typeset	O
representation	O
of	O
the	O
document	O
together	O
with	O
its	O
interactive	O
behaviour	O
.	O
</s>
<s>
In	O
the	O
on-screen	O
representation	O
of	O
the	O
TeXmacs	B-Application
tree	O
,	O
the	O
cursor	O
movement	O
represents	O
the	O
movement	O
inside	O
the	O
tree	O
.	O
</s>
<s>
On	O
disk	O
,	O
three	O
representations	O
of	O
the	O
TeXmacs	B-Application
format	O
exist	O
:	O
a	O
native	O
representation	O
,	O
an	O
XML	B-Protocol
representation	O
and	O
a	O
representation	O
with	O
Scheme	B-Language
S-expressions	O
;	O
the	O
Scheme	B-Language
representation	O
is	O
useful	O
for	O
the	O
interfacing	O
with	O
Scheme	B-Language
programs	O
.	O
</s>
<s>
The	O
typesetting	O
process	O
converts	O
TeXmacs	B-Application
trees	O
into	O
boxes	O
.	O
</s>
<s>
Evaluation	O
of	O
TeXmacs	B-Application
trees	O
proceeds	O
by	O
reduction	O
of	O
the	O
primitives	O
,	O
that	O
is	O
by	O
evaluation	O
of	O
macro	O
applications	O
.	O
</s>
<s>
TeXmacs	B-Application
uses	O
a	O
global	O
algorithm	O
for	O
"	O
line-breaking	O
"	O
(	O
similar	O
to	O
the	O
TeX	B-Application
one	O
)	O
and	O
in	O
addition	O
uses	O
a	O
global	O
algorithm	O
for	O
"	O
page-breaking	O
"	O
;	O
the	O
page-breaking	O
algorithm	O
takes	O
into	O
account	O
floating	O
objects	O
(	O
figures	O
,	O
table	O
,	O
footnotes	O
)	O
and	O
multi-column	O
content	O
.	O
</s>
<s>
Documents	O
can	O
be	O
controlled	O
through	O
a	O
native	O
macro	O
system	O
and	O
through	O
Guile-Scheme	O
.	O
</s>
<s>
TeXmacs	B-Application
macros	O
provide	O
a	O
means	O
of	O
structured	O
input	O
(	O
as	O
in	O
TeX/LaTeX	O
)	O
and	O
they	O
are	O
immediately	O
typeset	O
,	O
at	O
the	O
same	O
time	O
maintaining	O
editable	O
input	O
fields	O
.	O
</s>
<s>
They	O
are	O
written	O
in	O
source	O
code	O
,	O
although	O
the	O
WYSIWYG	B-Application
editor	I-Application
can	O
aid	O
in	O
their	O
composition	O
through	O
the	O
translation	O
of	O
visual	O
structures	O
into	O
their	O
syntax	O
.	O
</s>
<s>
Scheme	B-Language
is	O
embedded	O
in	O
TeXmacs	B-Application
through	O
GNU	B-Application
Guile	I-Application
;	O
the	O
editor	O
itself	O
can	O
be	O
controlled	O
in	O
this	O
way	O
:	O
menus	O
and	O
keybindings	O
can	O
be	O
customized	O
.	O
</s>
<s>
Scheme	B-Language
commands	O
can	O
be	O
invoked	O
interactively	O
inside	O
TeXmacs	B-Application
documents	O
,	O
can	O
be	O
invoked	O
from	O
the	O
command	O
line	O
and	O
from	O
inside	O
TeXmacs	B-Application
macros	O
.	O
</s>
<s>
TeXmacs	B-Application
trees	O
can	O
be	O
passed	O
to	O
Scheme	B-Language
in	O
different	O
forms	O
:	O
as	O
"	O
passive	O
trees	O
"	O
(	O
convenient	O
to	O
manipulate	O
content	O
directly	O
using	O
standard	O
Scheme	B-Language
routines	O
on	O
lists	O
)	O
,	O
as	O
"	O
active	O
trees	O
"	O
(	O
keep	O
track	O
of	O
the	O
position	O
of	O
the	O
tree	O
inside	O
the	O
global	O
document	O
tree	O
and	O
can	O
be	O
used	O
to	O
programmatically	O
modify	O
documents	O
)	O
,	O
and	O
in	O
a	O
"	O
hybrid	O
"	O
representation	O
.	O
</s>
<s>
Graphics	O
objects	O
are	O
also	O
part	O
of	O
the	O
TeXmacs	B-Application
format	O
and	O
can	O
be	O
manipulated	O
programmatically	O
from	O
Scheme	B-Language
.	O
</s>
<s>
An	O
example	O
of	O
TeXmacs	B-Application
graphics	O
generated	O
in	O
a	O
TeXmacs	B-Application
Scheme	B-Language
session	O
is	O
shown	O
below	O
together	O
with	O
the	O
session	O
which	O
generated	O
the	O
image	O
.	O
</s>
<s>
Images	O
generated	O
programmatically	O
in	O
a	O
Scheme	B-Language
session	O
can	O
also	O
be	O
edited	O
using	O
the	O
internal	O
drawing	O
editor	O
,	O
as	O
they	O
are	O
inserted	O
in	O
the	O
document	O
as	O
a	O
tree	O
;	O
Scheme	B-Language
scripts	O
can	O
also	O
be	O
executed	O
through	O
the	O
extern	O
TeXmacs	B-Application
macro	O
—	O
in	O
this	O
case	O
only	O
the	O
typeset	O
material	O
is	O
available	O
in	O
the	O
document	O
and	O
no	O
direct	O
editing	O
is	O
possible	O
(	O
the	O
modifications	O
must	O
be	O
made	O
within	O
the	O
Scheme	B-Language
code	O
)	O
.	O
</s>
<s>
TeXmacs	B-Application
has	O
back-ends	O
supporting	O
many	O
technologies	O
.	O
</s>
<s>
Plugin	O
output	O
can	O
be	O
embedded	O
within	O
TeXmacs	B-Application
documents	O
using	O
"	O
executable	O
switches	O
"	O
;	O
in	O
this	O
way	O
one	O
can	O
switch	O
back	O
and	O
forth	O
between	O
a	O
given	O
input	O
to	O
the	O
system	O
and	O
the	O
corresponding	O
output	O
,	O
which	O
blends	O
seamlessly	O
in	O
the	O
document	O
.	O
</s>
