perm filename AP.DOC[AP,SYS] blob
sn#019011 filedate 1973-01-08 generic text, type T, neo UTF8
READING THE ASSOCIATED PRESS NEWS
By Martin Frost
8 Jan 73
ABSTRACT:
We have a line from the Associated Press (AP) over
which we get national and international news (no
local news). The line is read by a program that
takes incoming news stories and files them away on
the disk, keeping about 24 hours' worth of news on
file at any given time. This document (which exists
as the file APE.ME[UP,DOC]) describes usage of
programs that allow access to the AP news.
8 Jan 73 AP News Page 1
We have a line from the Associated Press (AP) over which we get
national and international news (no local news). The line is read by
a program that takes incoming news stories and files them away on the
disk, keeping about 24 hours' worth of news on file at any given
time. This document (which exists as the file APE.ME[UP,DOC])
describes usage of programs that allow access to the AP news.
For use in reading the news, there are two programs on the system.
The first of these is HOT, which is a very small program that simply
types out the stories as they come in (at a somewhat slow rate of 6
2/3 characters/sec). The second program is APE, which enables the
user to read selectively the news that is on file.
To use the hot line, simply type the monitor command: R HOT. The
program should type back: "...Associated Press news..."; if it
doesn't, then it is having trouble contacting the program [-AP-],
which listens to the AP line. In this case, the program will try for
thirty seconds to contact [-AP-], after which time it will give up
and tell you so. After "...Associated Press news..." is typed out,
you will get whatever news is coming in. (There are times, usually
of only a few minutes duration, when no news is coming in; at such
times, HOT will of course type out nothing.) WARNING: Typing ↑C or
holding the typeout while the news is coming in will probably cause
HOT to miss some characters. If that happens, your job number will
be scratched from the list of jobs getting the hotline news; so you
will have to restart HOT.
From time to time, you may get stuff from HOT that looks like
garbage; in fact, it IS garbage resulting apparently from a hardware
problem with the teletype line over which the stories come. When
this happens, it will eventually correct itself, but this may take
anywhere from a few seconds to an hour.
Now before describing the second program (APE), I will explain a few
things about AP news stories. First of all, each story has a
sequence number which comes at the beginning of the story and a date
and time that come at the end. The sequence numbers start over every
day, with the first story that comes after about midnight EST getting
number 001. The time at the end of each story is the approximate New
York time when the story was sent over the wire.
Every twelve hours (at about noon and midnight EST) there is a news
digest that summarizes the stories that are known to be coming in
over the next twelve hours. The digest at midnight is usually story
number 002 and the one at noon usually number 202. The digests are
(usually) not categorized; to get them you must use one of the two
methods described in paragraph 1 under SPECIAL FEATURES.
8 Jan 73 AP News Page 2
Every day there are many stories that are corrections or additions to
previous stories. We (usually) link up such a follow-up with the
original and treat the resultant combination as one story, although
it may be made up of two, three, or even more separately numbered
stories. Any attempt to retrieve with APE any story of such a group
will result in retrieval of all parts of the group in chronological
order. (A long story will be broken up into smaller parts by the
Associated Press; the smaller parts are called TAKES and each gets
its own sequence number. We try to link all takes of the same story
together just like additions and corrections. Sometimes, however, a
take gets linked to some other story by mistake.)
THE ASSOCIATED PRESS EXTRACTOR (APE)
The program that is used to retrieve news is called APE. It allows
quick access to the stories because of a data structure that is
continually being updated by other programs. As each story comes in
over the AP wire, it is categorized by keywords from a special list
(the keyword dictionary). For each keyword in the dictionary a list
is kept of all the stories that word occurs in. To access the news,
you select the keyword or combination of keywords that you wish to
read about. A keyword can be either a single word (or number) or a
sequence of words (and/or numbers). For example, the following are
some possible keywords: WELFARE, WAR, SAN FRANCISCO, UNITED STATES,
UNION OF SOVIET SOCIALIST REPUBLICS, PDP 10, etc.
(The keyword dictionary contains about 1000 words, mostly people's
names and names of places (cities, states, countries). This list is
expandable, and if you have any words you would like added to the
list, SEND a note to ME. To see a list of the keywords, TYPE the
file WORDS.SRT[AP,SYS] or SPOOL the file WORDS.LST[AP,SYS].)
KEYWORD EXPRESSIONS
To retrieve stories using APE, you type in a KEYWORD EXPRESSION,
which may be either a single keyword or an expression containing
keywords and the operators +, -, and *. Each keyword represents the
set of all the stories it occurs in. And the operators represent the
set operations UNION (+), INTERSECTION (*), and SET DIFFERENCE (-),
which are performed on the sets of stories which the keywords
represent. Thus, if you want all stories that mention both Nixon and
8 Jan 73 AP News Page 3
McGovern, you should type the keyword expression "NIXON*MCGOVERN".
The precedence of operators is the normal one: * takes precedence
over + and -, which have equal precedence. Operations which have
equal precedence are evaluated from left to right. Parentheses may
be used freely in keyword expressions. Note that + and - are BINARY
operators only.
To clarify all this a little, here are a few examples:
Keyword Expression Meaning
--------------------------------- --------------------------------
(NIXON-WALLACE+MCGOVERN)*ELECTION All stories that mention both
ELECTION and either (1) NIXON
and not WALLACE or (2) MCGOVERN
(and possibly WALLACE).
ELECTION-NIXON-WALLACE-MCGOVERN All stories that mention
ELECTION but that mention none
of NIXON, WALLACE and MCGOVERN.
SAN FRANCISCO+LOS ANGELES-WAR All stories that mention either
SAN FRANCISCO or LOS ANGELES,
but not WAR.
Note: Spaces are needed only to separate individual words of multiple
word keywords, but they may be used anywhere except in the middle of
a word or special form.
RUNNING APE
To run APE, type the monitor command: R APE. When APE starts up it
reads in various files, and it is possible that another program will
have hold of one of those files. In that case, APE will say "One
moment please..." and will wait until it can grab the file. After
all the files have been read in, APE will respond with "KEYWORD
EXPRESSION:"; you should then type in a keyword expression as defined
in the last section. APE will count the stories that match your
expression and tell you how many stories it has found, such as:
5 news item(s) found. Selection:
At this point, you can select any contiguous group from the stories
8 Jan 73 AP News Page 4
found. For example, you can read the oldest 4 stories of those
matching your keywords, or you can read the newest 3, or the 2nd
through the 4th, or all of them, or none of them, etc. And you can
have the stories you select typed out, spooled (on the line printer)
and/or saved in a file on your disk area, all by typing in the
appropriate selection line as explained below.
The syntax for the selection line is as follows, where [...] denotes
an optional quantity and ...|... denotes exclusive alternatives: (The
order is irrelevant except that any filename must come first.)
[ <filenm> [/Q|/X] ← ] <story selection> [=] [S] [K] [F|C|L|D]
<filenm> is a filename of up to 6 characters (no extension or PPN is
allowed). If the <filenm> term is present, the stories selected
will be saved in the given file. If you do not say either /Q or
/X after the filename, then if the file already exists, you will
be told so and asked what to do. The presence and end of the
<filenm> term is indicated by the left arrow (←). File output is
not allowed with the F or L options (see below).
/Q following the filename means replace file if it already exists.
/X following the filename means extend file if it already exists.
The <story selection> indicates which stories you wish to select from
those found. It also indicates in what order you want to read the
stories. The syntax for <story selection> is:
N | <nbr>[:<nbr>] | <empty>
where <nbr> is a positive or negative integer and <empty> is the
empty string. If a single integer (k or -k) appears, it indicates
how many stories you wish to read. If the number is positive, you
will get the k most recent stories; if the number is negative, you
will get the k oldest stories. In either case, the stories will
come out in reverse chronological order, that is, newest stories
first. Two integers separated by a colon (:) indicate a range of
stories. For instance, "2:4" represents the second through the
fourth most recent stories. Negative numbers in this construction
represent the oldest stories; for example, "-2:-4" represents the
second oldest story through the fourth oldest story in that order.
The stories will come out in the order specified; that is, "-4:-2"
represents the same stories as "-2:-4" but in opposite order. If
the <story selection> is <empty>, then all the stories are
selected in reverse chronological order.
N means select None of the stories.
= means reverse the order in which the stories come out.
S means Spool the selected stories (not allowed with F or L options).
K means Kill automatic reading from command file (see section below
on command files).
8 Jan 73 AP News Page 5
F means type out only the First few lines of each story.
C means Choose which stories get typed out completely (see below).
L means type out only the Last few lines of each story.
D means Dont type out the stories at all (useful if you are saving
the stories in a file or spooling them).
If you use the Choose feature, then for each story the first few
lines will be typed out and you will be expected to indicate whether
you want to read the rest of the story. If you do not want to read
the rest of the story, type just carriage return. To read the rest
of the story, type altmode, linefeed, or any character followed by
carriage return. The character(s) you type will not be echoed, so
the story will appear unbroken. You will be allowed to quit reading
a story at the beginning of each part (take, correction, etc.) of the
story. If you are saving stories in a file or spooling them, then
only those you choose to read will be put in the file and/or spooled.
Here are some selection line examples and their meanings.
2 Type out the newest two stories.
-2 Type out the oldest two stories.
=2 Type out the newest two stories in chronological order.
(Normal order is reverse chronological order.)
F2 Type only the first few lines of each of the two newest
stories.
-2:5 Type out the 2nd oldest story through the 5th newest
story.
=5:-2 Same as -2:5.
2:2 The only way to get just the 2nd newest story.
= Type out all the stories in chronological order.
FOO← Type out all the stories and save them in the file FOO.
FOO/Q←D Dont type out anything, but put all stories into the
file FOO. If the file already exists, then delete the
old version.
FOO/X←SC5 For the newest 5 stories, type out the first few lines
and let me Choose whether I want to see the rest of
8 Jan 73 AP News Page 6
the story. Extend the file FOO with any stories I
choose and then spool it.
L Type out only the last few lines of each story. (The
last few lines include mainly the time and date of the
story.)
N Do Nothing with the stories found. (Get next keyword
expression.)
------------
If you ask for the stories to be saved in a file, the file will be
given the standard extension ".AP" and will be put on your own disk
area (or your ALIAS area if you currently have an ALIAS). If you ask
for the stories to be spooled but not saved in a file, APE will
create a file with a name like $NEWS0.AP, which will be spooled and
then deleted. (The file $NEWS0.AP will be put on your real disk area
so that the spooler can delete it.)
SEARCHING THE NEWS FILE
While parsing an expression, if a keyword is encountered that is not
in the keyword dictionary, you will be told so and asked if you would
like a search done for that keyword in the news. If you want a
search done, type "Y" (without a carriage return) for Yes. Type
anything else if you dont want a search.
During a search, every time a story is found containing the searched
for keyword, an asterisk (*) will be typed out. Should you wish to
discontinue the search at any time, merely type any character. Any
stories found up to that time will represent the particular keyword
in the expression as if searching had gone to completion. Stories
are searched in the order of newest to oldest. For every keyword not
in the dictionary, a separate search must be done. However, once you
have said Yes to searching, subsequent keywords in the same
expression will be searched for automatically without your being
asked. You may, of course, interrupt such a search by typing any
character.
Multiple word keywords may be searched for just like single word
keywords, but only those instances where the whole multiple word
keyword occurs on the same line in the news will be found (this is
the result of an important search optimization).
8 Jan 73 AP News Page 7
Searching the whole news file for a keyword takes about 8 to 10
seconds of computer time. If, however, an unrecognized keyword
occurs as the second part of an intersection or difference operation
(eg, NIXON * JJJJ or NIXON - JJJJ), then only the necessary stories
are searched and the search time is generally very much smaller.
COMMAND FILE INPUT
If, in place of a keyword expression, you type an at-sign (@)
followed by a file name (extension and/or PPN allowed!), then APE
will endeavor to read a keyword expression and then possibly a
selection line from the file. APE can handle most (if not all) text
file formats, including SOS and TVEDIT. After you have opened a
command file in this manner, if you type just an at-sign for a
keyword expression, APE will read another keyword expression (and
selection line) from the command file. This can continue until the
end of the file is reached, at which time APE will type out [EOF] to
let you know.
If you follow the at-sign in either case above with an exclamation
point (!), then APE will automatically read from the command file
whenever a keyword expression is needed. This automatic reading from
the command file can be stopped by using the K option in the
selection line (see above). This cancels the effect of the
exclamation point. Another way to disable automatic command file
reading is to type ↑C and then the system REEnter command. Any error
in an expression read from the file will also disable automatic
reading.
If you type an at-sign (and optionally an exclamation point) without
a filename at a time when you have no command file open, then the
standard command file name APE.CMD will be used. You may open the
file APE.CMD on someone else's disk area by typing, for example,
"@[FOO,BAZ]" or "@![FOO,BAZ]".
Now a word about what a command file should look like.
When reading from a command file, APE will read until a semicolon (;)
or comma (,) is found. All carriage returns, linefeeds and form
feeds (page marks) are completely ignored. (That means a keyword can
be split between two lines or even two pages!) If, when reading a
keyword expression from a file, a comma is encountered, then the
stuff following the comma and up to the next comma or semicolon is
assumed to be the selection line you want for this particular keyword
8 Jan 73 AP News Page 8
expression. On the other hand, if a keyword expression is terminated
with a semicolon, the selection line will be read from the console
instead. Selection lines in a command file should end with a
semicolon. If one ends with a comma, everything up to the next
semicolon will be ignored.
Every keyword expression and selection line read from a command file
will be typed out preceded by an at-sign to indicate that it came
from the file.
Finally, whenever an unrecognized keyword is read from a command
file, it is automatically searched for without your being asked. You
can, of course, always interrupt the search by typing any character.
Here is a sample command file:
TELEVISION+TV; MOVIES,; THEATRE,C; STAGE,STAG/X←C;
This file contains four keyword expressions. If any stories about
TELEVISION or TV are found, the user will be allowed to type in his
own selection line. Then, if any stories about MOVIES are found,
they will automatically be typed out (note the empty selection line
between the comma and the semicolon). If any stories about THEATRE
are found, the user will be allowed to choose which ones he wants.
If any stories about STAGE are found, the user will be allowed to
choose which ones he wants, and those he picks will be added to the
file STAG.
8 Jan 73 AP News Page 9
SPECIAL FEATURES
1. In addition to normal English keywords, there are two special
forms that can be used as keywords in expressions. The first
consists of a period (.) followed by an unsigned integer, eg., ".18";
if k is the integer following the period, this form represents the
set of the newest k stories that have come in. The second special
form consists of a number sign (#) followed by an unsigned integer;
this form represents all the stories that have the given integer as
their AP sequence number. This feature is especially useful for
reading the AP news digests because they are not categorized at all.
The only way to get them is to use one of the special forms.
(Actually, stories #1, #2, #201 and #202 are the ones not
categorized; occassionally the digest has some other sequence number
so it gets categorized.) Here are some examples of keyword
expressions using these special forms.
CHESS * .10 Among the last 10 stories that
have come in, all those that
mention CHESS.
#2 + #202 All stories with either of these
sequence numbers. (These are the
usual sequence numbers of the
news digests.)
2. The null keyword expression (that is, typing just CARRIAGE RETURN
without any keywords) has a special value: the set of stories
corresponding to the previous keyword expression. These stories
constitute your CURRENT STORY LIST. With this feature you can get
back a second time the stories you just looked at. In fact, this
feature can be used consecutively any number of times, giving the
same stories every time.
3. Whenever APE is expecting input, if you type a question mark (?)
and carriage return, APE will type out an explanation of what you are
to type in.
4. A keyword expression may be continued over several lines. Simply
type a LINEFEED anywhere except in the middle of a word and APE will
type a carriage return and a colon (:) and wait for you to type in
more of the expression.
5. Your current story list can be modified without typing again the
keywords you used to get it. If a keyword expression starts with +,
8 Jan 73 AP News Page 10
-, or *, the missing (first) operand is taken to be your current
story list. For example, if you have typed in "NIXON" as your last
keyword expression, you can type in "*VIETNAM" as your next
expression and you will get only stories that mention both NIXON and
VIETNAM.
6. When stories are typed out or written in a file, a row of stars
(*'s) is placed between stories. Note that corrections and additions
to a story are considered part of that story; thus they will not be
separated from it by a row of stars.
7. If you type ↑O ([ESC] O on Stanford displays) during typeout of a
story, the typeout will be stopped (as usual), but will start up
again with the next story (if any).
8. If you type ↑C and then the system REEnter command, APE will be
back to asking for keywords, and your current story list will not
have been changed. (That is, you can get it back by typing just
carriage return; see paragraph 2 above.) Any file or spooler output
going on when you do this is wiped out except that when extending an
old file any output already done is permanent. Reentering also
disables automatic reading from a command file. Exactly the same
effect as ↑C and REE can be gotten on Stanford displays by typing
merely [ESC] I.
9. Upper and lower case characters are always equivalent.
****** THE NEXT TWO FEATURES (10 AND 11, AUTOMATIC NOTIFICATION)
****** HAVE NOT YET BEEN IMPLEMENTED!!!
10. If a keyword expression is preceded by a dollar sign ($), APE
will interpret that to mean that you wish to be notified whenever a
story comes in that fits the expression. (You will still be told how
many stories currently fit the expression.) Whenever such a story
does come in, a message will be sent to you through the standard
message system (a la system SEND command). Also, if you are logged
in at the time the story comes in, the message will be typed out on
your console. The message will say something like:
MESSAGE FROM AP MONITOR:
FOUND (PEACE*WAR ENDS IN VIETNAM) IN STORY #321
04-JLY-76 1019et AP,SYS
where the time and date are in Eastern Time (et) so that you can find
the story later. (The time that appears at the end of the story is
in Eastern Time, and so it should be very close to that given in the
message.) Notification is on the basis of your logged in programmer
name.
8 Jan 73 AP News Page 11
11. If a keyword expression is preceded by a slash (/), APE will
interpret that to mean that you want notification for this expression
to be stopped. This cancels the previous effect of the same
expression preceded by a dollar sign. No error indication will be
given if you have never requested notification for this expression.
If you type only a slash as a keyword expression, then notification
will be stopped for all expressions for which you currently have a
request in (on the basis of your logged in programmer name). Every
notification request will be purged eventually, either after a
certain length of time, or after a certain number of stories have
been found; the limits have not yet been set, however.
NOTES
First, the news is kept in a fixed size file. This means that
occasionally an old story must be deleted to make room for a new one.
If this happens after you start APE, and if you attempt to read such
a deleted story, then you will get a message something like "1 OF THE
STORIES WENT AWAY--SORRY".
Finally, news that comes in after you start APE cannot be retrieved.
If you want to update APE's data to include the latest stories, type
↑C and then the system START command. (When you do this your current
story list will be re-initialized to null.)