perm filename SAIL.DOC[DOC,AIL]6 blob
sn#128046 filedate 1974-11-03 generic text, type T, neo UTF8
STANFORD ARTIFICIAL INTELLIGENCE LABORATORY NOVEMBER 1974
SAIL USER MANUAL
UPDATE
James R. Low
John F. Reiser
Hanan J. Samet
Robert L. Smith
Robert F. Sproull
Daniel C. Swinehart
Russell H. Taylor
Kurt A. VanLehn
ABSTRACT
This document describes recent changes to the SAIL language since the
"new" manual (AIM-204) was published in July 1973. It reflects the
various new features implemented as of 24 October, 1974 for SAIL
version 8 and corrects a number of minor errors in the earlier
manual.
SAIL Addendum 1 TABLE OF CONTENTS
T A B L E O F C O N T E N T S
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
SECTION PAGE
1 INTRODUCTION 1
2 NUMERICAL ROUTINES 2
1 OVERFLOW 3
2 ENTRY POINTS 4
3 NEW PROCESS FEATURES 5
1 SPROUT APPLY 5
2 SPROUT_DEFAULTS 5
3 SUSPEND 7
4 FAIL AND SUCCEED 7
4 ERROR HANDLING 8
1 ERROR MODES 8
2 USER ERROR PROCEDURES 8
5 INEXHAUSTIBLE STRING SPACE 11
6 RECORD STRUCTURES 13
1 INTRODUCTORY REMARKS 13
2 RECORD CLASS DECLARATIONS 14
3 RECORD POINTER DECLARATIONS 14
4 ALLOCATION 15
5 SUBFIELDS 16
6 INTERNAL REPRESENTATIONS AND IMPLEMENTATION NOTES 17
SAIL Addendum 1 TABLE OF CONTENTS
7 MISCELLANEOUS NEW FEATURES 19
1 NEW MTAPE OPTIONS 19
2 INITIALIZATION PHASES 19
3 CHNCDB 20
4 ARRCLR 20
5 SETPL 21
6 EVALREDEFINE 21
7 CVPS 21
8 EXPRESSIONS IN REQUIRES 21
9 RELEASE 22
10 TTYUP 22
11 BREAKSET MODES "K" AND "F" 22
12 INOUT 23
13 GETSTS & SETSTS 23
14 CHANGES TO "OPEN" ERROR HANDLING 23
15 ASH 24
16 ARG_LIST 24
17 CLOSE 24
18 TYPEIT 25
19 COMPARISON OF .REL FILES 25
20 SCAN Optimizations 25
21 BREAK TABLES 25
22 TENEX RUNTIMES 26
SAIL Addendum 1 INTRODUCTION
SECTION 1
_______ _
INTRODUCTION
____________
The following short manual describes the changes that have happened
to SAIL since the publishing of the Manual in July 1973. It
accurately reflects the state of SAIL, version 7, which was put up on
December 4, 1973. The reader should be warned that many of these new
features were designed for veteran SAIL hackers.
The reader may also want to refer to the following documents, which
are usually kept updated.
MACLIE.WRU[DOC,AIL] A summary of commonly made errors when using
macros and what to do about them.
TUTOR.DOC[DOC,AIL] In introduction to LEAP.
LEAP.WRU[DOC,AIL] A detailed description of the runtime environment
of LEAP for the hardy few who want to interface
to LEAP in assembly language.
SAIL.DOC[AIM,DOC] The July '73 manual (AIM-204) in LPT form.
Warning: this version is the Stanford character
set. It is also almost 300 pages long. You can
get a 120 page version, set in two columns of
nice type from the National Technical Information
Service, Springfield, Virginia 22151.
LIES[DOC,AIL] This file contains the know mistakes in the
Manual. Soon it will also contain the known
mistakes in this document.
1
SAIL Addendum 1 NUMERICAL ROUTINES
SECTION 2
_______ _
NUMERICAL ROUTINES
_________ ________
A collection of numerical routines has been added to SAIL. These are
pre-declared in the compiler, and are loaded from the standard SAIL
library. The functions are quite standard; following are the
equivalent definitions:
1. The standard trigonometric functions. ASIN, ACOS, ATAN and ATAN2
return results in radians. The ATAN2 call takes arc-tangent of
the quotient of its arguments; in this way, it correctly
preserves sign information.
REAL PROCEDURE SIN (REAL RADIANS);
REAL PROCEDURE COS (REAL RADIANS);
REAL PROCEDURE SIND (REAL DEGREES);
REAL PROCEDURE COSD (REAL DEGREES);
REAL PROCEDURE ASIN (REAL ARGUMENT);
REAL PROCEDURE ACOS (REAL ARGUMENT);
REAL PROCEDURE ATAN (REAL ARGUMENT);
REAL PROCEDURE ATAN2 (REAL NUMERATOR,DENOMINATOR);
2. The hyperbolic trigonometric functions.
REAL PROCEDURE SINH (REAL ARGUMENT);
REAL PROCEDURE COSH (REAL ARGUMENT);
REAL PROCEDURE TANH (REAL ARGUMENT);
3. The square-root function:
REAL PROCEDURE SQRT (REAL ARGUMENT);
4. A pseudo-random number generator. The argument specifies a new
value for the seed (If the argument is 0, the old seed value is
used. Thus to get differing random numbers, this argument should
be zero.) Results are normalized to lie in the range [0,1].
REAL PROCEDURE RAN (INTEGER SEED);
2
SAIL Addendum 1 NUMERICAL ROUTINES
5. Logarithm and exponentiation functions. These functions are the
same ones used by the SAIL exponentiation operator. The base is
e (2.71828182845904). The logarithm to the base 10 of e is
.4342944819.
REAL PROCEDURE LOG (REAL ARGUMENT);
REAL PROCEDURE EXP (REAL ARGUMENT);
These functions may occasionally be asked to compute numbers that lie
outside the range of legal floating-point numbers on the PDP-10. In
these cases, the routines issue sprightly error messages that are
continuable.
2.1 - OVERFLOW
________
In order to better perform their tasks, these routines enable the
system interrupt facility for floating-point overflow and underflow
errors. If an underflow is detected, the results are set to 0 (a
feat not done by the PDP-10 hardware, alas). Be aware that such
underflow fixups will be done to every underflow that occurs in your
program.
If you would like to be informed of any numerical exceptions, you can
call the runtime:
TRIGINI ( LOCATION(simple-procedure-name) );
Every floating-point exception that is not expected by the interrupt
handler (the numerical routines use a special convention to indicate
that arithmetic exception was expected) will cause the specified
simple procedure to be called. This procedure may look around the
world as described in the Manual for 'export' interrupt handlers,
page 79. If no TRIGINI call is done, the interrupt routine will
simply dismiss unexpected floating-point interrupts.
3
SAIL Addendum 1 NUMERICAL ROUTINES
2.2 - ENTRY POINTS
_____ ______
In order to avoid confusion (by the loader) with older trig packages,
the entry points of the SAIL arithmetic routines all have a "$"
appended to the end. Thus, SIN has the entry point SIN$, etc.
WARNING: If a program plans to use the SAIL intrinsic numerical
routines, it should NOT include external declarations to them, since
this will probably cause the FORTRAN library routines to be loaded.
4
SAIL Addendum 1 NEW PROCESS FEATURES
SECTION 3
_______ _
NEW PROCESS FEATURES
___ _______ ________
3.1 - SPROUT APPLY
______ _____
The <procedure call> in a SPROUT statement may be an APPLY construct.
In this case SPROUT will do the "right" thing about setting up the
static link for the APPLY. That is, "up-level" references by the
process will be made to the same variable instances that would be
used if the APPLY did not occur in a SPROUT statement. (See page 77
of the manual.)
However, there is a glitch. The sprout mechanism is not yet smart
enough to find out the block of the declaration of the procedure used
to define the procedure item. It would be nice if it did, since then
it could warn the user when that block was exited and yet the process
was still alive, and thus potentially able to refer to deallocated
arrays and etc. What the sprout does instead is assume the procedure
was declared in the outer block. This may be fixed eventually, but
in the meantime some extra care should be taken when using apply
in sprouts to avoid exiting a block with dependents.
Similarly, be warned that the "DEPENDENTS (<blockid>)" construct
may not give the "right" result for sprout applies. Page 68 of
the Manual contains the description of this protection mechanism for
non-APPLY Sprouts.
3.2 - SPROUT_DEFAULTS
_______________
SAIL now provides a mechanism by which the user may specify the
"default" options to be used when individual procedures are sprouted.
5
SAIL Addendum 1 NEW PROCESS FEATURES
Syntax:
PROCEDURE <procid> ...
BEGIN
<some declarations>;
SPROUT_DEFAULTS <integer constant>;
<perhaps some more declarations>;
:
:
<statements>
:
END;
In other words, SPROUT_DEFAULTS is a declaration.
Semantics:
If one of the "allocation" fields of the options word passed to the
SPROUT routine -- i.e. QUANTUM,STRINGSTACK,PSTACK, or PRIORITY -- is
zero, then SPROUT will look at the corresponding field of the
specified <integer constant> for the procedure being sprouted. If the
field is non-zero, then that value will be used; otherwise the
current "system" default will be used.
NOTE: SPROUT_DEFAULTS only applies to "allocations", i.e. the
process status control bits (e.g. SUSPME) are not affected.
Example:
RECURSIVE PROCEDURE FOO;
BEGIN
SPROUT_DEFAULTS STRINGSTACK(10);
INTEGER XXX;
:
:
END;
:
SPROUT(P1,FOO,STRINGSTACK(3));
SPROUT(P2,FOO);
COMMENT P1 will have a string stack of 3*32 words.
P2 will have a string stack of 10*32 words;
6
SAIL Addendum 1 NEW PROCESS FEATURES
3.3 - SUSPEND
_______
SUSPEND now behaves like RESUME in that it returns an item.
itm ← SUSPEND(<process item>)
Frequently, one is suspending some other process than the one that is
executing the SUSPEND statement. In this case, the item returned is
ANY. However, in cases like:
X ← SUSPEND(MYPROC);
where the process suspends itself, it might happen that this process
is made running by a RESUME from another process. If so, then X
receives the <return_item> that was an argument to the RESUME.
3.4 - FAIL AND SUCCEED
____ ___ _______
FAIL and SUCCEED now behave like RESUME and SUSPEND in that they also
return an item. The item returned is ANY unless the Matching
Procedure containing the FAIL or SUCCEED was (1) sprouted as a
process, and (2) made running by a RESUME construct. In the latter
case, the item returned is the <return_item> that was an argument to
the RESUME. [Note that the only case in which a Matching Procedure
can be reactivated at a FAIL is by being RESUMEd.]
7
SAIL Addendum 1 ERROR HANDLING
SECTION 4
_______ _
ERROR HANDLING
_____ ________
4.1 - ERROR MODES
_____ _____
SAIL's error handler has at long last been modified to do what is
claimed it will do in Section 20 of the manual (pgs 95 - 97), and in
the description of USERERR (pg 42). In brief, it allows one to have
error messages automatically sent to a "log" file while one is
compiling, and to use USERERR as a trace statement.
The description given in the manual differs from reality in two ways:
"Keep" mode has not been implemented (the error handler will flush
all type-ahead except a <lf>); all of the other modes ("Quiet",
"Logging", and "Numbers") are implemented ONLY IN THE COMPILER.
However, one can get the effect of error modes at runtime by using a
brand new feature called user error procedures.
4.2 - USER ERROR PROCEDURES
____ _____ __________
A user error procedure is a user procedure that is run before or
instead of the SAIL error handler everytime an error occurs at
runtime. This includes all array errors, IO errors, Leapish errors
and all USERERRs. It does not include system errors, such as Ill Mem
Ref or Ill UUO.
The procedure one uses for a user error procedure must be of the
following type:
SIMPLE INTEGER PROCEDURE proc (INTEGER loc; STRING msg, rsp);
Only the names proc, loc, msg, and rsp may vary from the example
above, except that one may declare the procedure INTERNAL if one
wishes to use it across files.
8
SAIL Addendum 1 ERROR HANDLING
Whenever the external integer _ERRP_ is loaded with LOCATION(proc),
the error handler will call proc before it does anything else. It
will set loc to the core location of the call to the error handler.
Msg will be the message that it would have printed. Rsp will be
non-NULL only if the error was from a USERERR which had response
string argument. Proc can do anything that a simple procedure can
do. When it exits, it should return an integer which tells the
error handler if it should do anything more. If the integer is 0,
the error handler will (1) print the message, (2) print the
location, and (3) query the tty and dispatch on the response
character (i.e ask for a <cr>, <lf>, etc.). If the right half of the
integer is non-zero, it is taken as the ascii for a character to
dispatch upon. The left half may have two bits to control printing.
If bit 17 in the integer is on, message printing is inhibited. If
bit 16 is on, then the location printing is inhibited. For example,
"X"+(1 LSH 18) will cause the location to be printed and the program
exited. "C"+(3 LSH 18) will cause the error handler to continue
without printing anything.
Note that simple procedures can not do a non-local GOTO. However,
the effect of a non-local GOTO can be achieved in a user error
procedure by loading the external integer _ERRJ_ with the LOCATION of
a label. The label should be a on a call to a non-simple procedure
which does the desired GOTO. The error handler clears _ERRJ_ before
calling the procedure in _ERRP_. If _ERRJ_ is non-zero when the
user procedure returns, and continuing was specified, then the error
handler's exit consists of a simple transfer to that location.
WARNING! Handling errors from strange places like the string garbage
collector and the core management routines will get you into deep
trouble.
A user error procedure has been written which gives a traceback
through the run-time stack. The traceback routine lists the name of
each non-simple calling procedure and the location (in octal) of the
PUSHJ it did, starting with the most recently called procedure and
ending with the main procedure of the current process.
The procedure is currently available via REQUIRE "LIBSA7[1,JFR]"
LIBRARY or via REQUIRE "WALK.REL[1,JFR]" LOAD_MODULE. The procedure
will move to the system LIBSA7 as soon as possible.
To use the procedure say EXTERNAL PROCEDURE _TRON_; ... _TRON_;
COMMENT _TRON_ is for "trace on";.
Subsequent run-time errors will give the traceback, then request the
usual response. To get the traceback at any time, say EXTERNAL
9
SAIL Addendum 1 ERROR HANDLING
PROCEDURE WALK; ... WALK;. This can be useful in checking recursion
level or in other debugging.
To intercept the trackback, say EXTERNAL PROCEDURE UMWALK(INTEGER
LOC); ... UMWALK(LOCATION(user_procedure));. Then
user_procedure("NAME",LOC) is called once for every procedure in the
traceback chain, instead of printing "CALLED FROM "&NAME&" AT
"&CVOS(LOC)&CRLF on the terminal.
To discontinue tracing on errors: EXTERNAL INTEGER _ERRP_; ...
_ERRP_←0;.
10
SAIL Addendum 1 INEXHAUSTIBLE STRING SPACE
SECTION 5
_______ _
INEXHAUSTIBLE STRING SPACE
_____________ ______ _____
The string garbage collector has been modified to expand string space
(using discontiguous blocks) whenever necessary to satisfy the demand
for places to put strings. To take advantage of this feature, one
need not change his programs.
Here are some points which might be of interest, however:
1) Although we are going to provide user control over all size
parameters eventually, currently only the initial string
space size is settable by the user, either via REQUIRE or
the ALLOC sequence, as before. The size of each string space
increment will be the same as the original size, which need not
be monstrous any more unless you know that all runs of your
program will need a monstrous string space anyhow. The
threshold (see below) for expanding will be set at 1/8 the
string space size (increment size).
2) One can, in his program, modify these values independently, if he
is willing to use the USERCON function, and to follow this
format:
USER TABLE ENTRY NAME VALUE
STINCR lh: number of chars. in increment
rh: number of words in increment + 4
STREQD lh: number of chars. in threshold
rh: number of words in threshold.
3) The threshold. After garbage collection, let us say that M-1
discontiguous string spaces are full, and the M'th has n
free characters in it (available for new strings). The garbage
collector was called because some routine wanted to create a
string R characters long, and there were not that many available
(free). After garbage collection, the new algorithm
requires that N be greater than R+LH(STREQD). If it is not,
expansion takes place (to M+1 spaces), to satisfy this
requirement. In other words, if STREQD is 1/8 the size of the
current space, that space will not be allowed to become more
11
SAIL Addendum 1 INEXHAUSTIBLE STRING SPACE
than about 7/8 full. This helps avoid frequent, nearly
useless calls on the garbage collector when space is about gone.
All but the current space are allowed to become as full as
possible, however.
4) New statistics are maintained by the garbage collector.
Soon there will be a built-in routine you can use to print
them. For now, you may look at them using USERCON, although this
document does not say what they are. In order to
activate timing of the garbage collector (slows it down), set
SGCTIME in the user table to -1.
5) Future plans. The new structure not only allows expansion of
string space, it also will allow for partial garbage
collections (no visible benefits except increased speed,
since a partial collection will be almost as effective as a
complete one, and much faster), and the ability to move
string space blocks, in order to compact memory. Push on your
local representative to get these things done.
12
SAIL Addendum 1 RECORD STRUCTURES
SECTION 6
_______ _
RECORD STRUCTURES
______ __________
6.1 - INTRODUCTORY REMARKS
____________ _______
Record structures are a fairly recent addition to SAIL. Essentially,
they provide a means by which a number of closely related variables
may be allocated and manipulated as a unit, without the overhead or
limitations associated with using parallel arrays. In the current
implementation, each record is an instance of a user-defined "record
class", which serves as a template describing the various subfields
of the record. Internally, records are small blocks of storage which
contain space for the various subfields and a pointer to a class
descriptor. Subfields are allocated one per word and are accessed by
constant indexing off the record pointer. Deallocation is perormed
by a garbage collector.
Records were originally added to SAIL to fullfill a number of very
specific needs at Stanford, and were subsequently generalized to the
form seen here. The structures described in this section are
implemented and, so far as is known, work correctly. (They have been
used successfully over the past 3 months by several different people
to produce a number of sizable programs). However, a number of fine
points have yet to be cleaned up before SAIL records can be
considered to be "finished". Also, several aspects of the existing
implementation are still quite ugly, and may be substantially
modified in the future, although the language constructs seen by the
user are apt to stay about the same. The material presented here
should therefore be considered to be PRELIMINARY DOCUMENTATION ONLY.
It is being supplied only in response to numerous requests for such
documentation, and with the understanding that the system described
is still in an adolescent -- though usable -- stage. Readers are
strongly urged to look at the file RECAUX.SAI[CSP,SYS], which
contains a number of useful examples and auxilliary functions.
13
SAIL Addendum 1 RECORD STRUCTURES
6.2 - RECORD CLASS DECLARATIONS
______ _____ ____________
RECORD_CLASS <classid> (<subfield declarations>)
For instance,
RECORD_CLASS VECTOR (REAL X,Y,Z);
RECORD_CLASS CELL (RECORD_POINTER(ANY_CLASS) CAR,CDR);
RECORD_CLASS TABLEAU (REAL ARRAY A,B,C;INTEGER N,M);
RECORD_CLASS FOO(LIST L;ITEMVAR A);
Generally, the <subfield declarations> have the same form as a
procedure's formal paramter list, except that the words VALUE and
REFERENCE should not be used. Also, STRING subfields are not yet
implemented. Each record class declaration is compiled into a
"record descriptor" which is used by the runtime system for
allocation, deallocation, garbage collection, etc.
6.3 - RECORD POINTER DECLARATIONS
______ _______ ____________
RECORD_POINTER(<classid list>) <id list>
RECORD_POINTER(ANY_CLASS) <id list>
For instance,
RECORD_POINTER(VECTOR) V1,V2;
RECORD_POINTER(VECTOR,TABLEAU) T1,T2;
RECORD_POINTER(ANY_CLASS) R;
At runtime, these variables either contain the value NULL_RECORD
(internally, zero) or else contains a pointer to a record. The
<classid list> is used to make a compile-time check on assignments
and subfield references. The pseudo-class ANY_CLASS matches all
classes, and effectively disables this compile-time check. For
instance:
RECORD_POINTER(FOO,BAR) FB1,FB2;
RECORD_POINTER(FOO) FB3;
RECORD_POINTER(CELL) C;
RECORD_POINTER(ANY_CLASS) RP;
:
COMMENT the following are all ok syntactically;
14
SAIL Addendum 1 RECORD STRUCTURES
C←NEW_RECORD(CELL);
RP←C;
FB2←NEW_RECORD(FOO);
FB1←FB3;
FB3←RP; COMMENT Note that this is most likely a runtime bug
Since RP will contain a cell record. SAIL
won't catch it, however;
CELL:CAR[RP]←FB1;
COMMENT The compiler will complain about these: ;
FB1←C;
FB3←NEW_RECORD(CELL);
RP←CELL:CAR[FB3];
NO runtime class information is kept with the variable, and no
runtime class checks are made on record assignment or subfield
access. Record pointer variables are allocated quantities, and
should not appear inside SIMPLE procedures. They resemble lists in
that they are not given any special value upon block entry and they
are set to a null value (NULL_RECORD) when the block in which they
are declared is exited. (This is so that any records referred to
only in that block can be reclaimed by the garbage collector.)
6.4 - ALLOCATION
__________
Records are allocated by means of the construct
NEW_RECORD(<classid>)
which returns a new record of the specified class. All subfields of
the new record are set to the "null" or "zero" value for that
subfield -- i.e., real & integer subfields will be set to 0, itemvar
subfields will be set to ANY, lists will be set to PHI, etc. Again,
note that entry into a block with local record pointer variables does
NOT cause records to be allocated and assigned to those variables.
15
SAIL Addendum 1 RECORD STRUCTURES
6.5 - SUBFIELDS
_________
Record subfields are referenced by means of the construct
<classid>:<fieldid>[<record pointer expression>]
and may be used wherever an array element may be used. For example
RECORD_POINTER(VECTOR) V;
RECORD_POINTER(CELL) C;
RECORD_POINTER(FOO) F;
:
VECTOR:X[V]←VECTOR:Y[V];
CELL:CAR[C←NEW_RECORD(CELL)]←V;
VECTOR:Z[V]←VECTOR:X[CELL:CAR[C]];
SUBLIS ← FOO:L[F][1 TO 3];
:
If the <record pointer expression> gives a null record, then a
runtime error message will be generated. This is the only runtime
check that is made at present. I.e., no runtime checks are made to
verify that the <classid> in the subfield statement matches the class
of the record whose subfield is being extracted.
An array subfield may be used as an array name, as in
RECORD_POINTER(TABLEAU) T;
:
TABLEAU:A[T][I,J] ← 2.5;
provided that you have stored a valid array descriptor into the
subfield. Unfortunately, SAIL does not provide any clean way to do
this. One unclean way is
INTEGER PROCEDURE NEWARY(INTEGER LB,UB);
BEGIN
INTEGER ARRAY A[LB:UB];
INTEGER AA;
AA←MEMORY[LOCATION(AA)];
MEMORY[LOCATION(AA)]←0;
COMMENT defeats deallocation;
RETURN(AA);
END;
:
16
SAIL Addendum 1 RECORD STRUCTURES
RECORD_CLASS FUBAR(INTEGER ARRAY A);
RECORD_POINTER(FUBAR) FB;
:
MEMORY[LOCATION(FUBAR:A[FB])]←NEWARY(1,100);
(Warning: the above "advice" is primarily intended for hackers; we
make no promisses that it will never get you into trouble, although
this particular trick is unlikely to be made obsolete in the
forseeable future).
6.6 - INTERNAL REPRESENTATIONS AND IMPLEMENTATION NOTES
________ _______________ ___ ______________ _____
Records are allocated by a "small block" allocator that gets large
buffers of storage from the normal SAIL free storage system. Each
record currently has the following form:
-1: <used by garbage collector & free storage system>
0: 20,,<record class descriptor>
+1: <first subfield>
:
+n: <last subfield>
Record pointer variables point at word 0 of such records.
Eventually, we may do away with "-1" word altogether.
Record class descriptors currently have the form:
0: byte(13)length(5)0(18)<record handler procedure>
1: <descriptor for first field>
:
n: <descriptor for last field>
n+1: <SAIL-format string descriptor
n+2: for class name>
n+3: ascii text for class name
The normal value for the handler procedure is $REC$, which is the
standard procedure for such functions as allocation, deallocation,
etc. Currently, this procedure is usually called as the result of
user uuo RECUUO (=8). which, in turn, does a pushj p,@<effective
address>. Thus:
RECUUO OP,RV ;OP = minor op code. RV = record variable
goes (roughly to)
17
SAIL Addendum 1 RECORD STRUCTURES
<save acs>
PUSH P,[OP]
PUSH P,RV
PUSH P,[0] ;this extra argument is sort of random.
;It was intended for expansions. Instead,
;it may eventually be flushed.
PUSHJ P,@RV
< restore acs (except ac1) >
It is possible for a user to substitute his own handler procedure for
a given class of records by including the procedure name in brackets
after the record class declaration:
RECORD_CLASS <id> (<subfields>) [<handler>]
This handler must have the form
RECORD_POINTER(ANY_CLASS) PROCEDURE <procid>
(INTEGER OP;RECORD_POINTER(ANY_CLASS) R1,R2);
Where OP will be a small integer saying what is to be done. The
current assignments for OP are:
OP value meaning
0 invalid
1 allocate a new record with same type as R1
2 not used
3 not used
4 Mark all subfields of record R1
5 Delete all space for record R1
However, NO promisses are made concerning future assignments or,
indeed, concerning the general structure. This feature is primarily
intended for use by wizards, and others use it at their peril.
18
SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
SECTION 7
_______ _
MISCELLANEOUS NEW FEATURES
_____________ ___ ________
7.1 - NEW MTAPE OPTIONS
___ _____ _______
MTAPE(chan,NULL)
will cause an MTAPE 0 to be issued for channel chan. For mag. tapes,
this will cause you to wait until all activity ceases. For other
devices, various random things can happen, depending on the device
and system.
In export SAIL, MTAPE(chnl,"I") sets the 'IBM compatible' mode for a
tape drive. (It does an MTAPE chnl,101.)
These features do not work in TENEX SAIL. Full access to TENEX
magtapes is obtained through the MTOPR, GDSTS and SDSTS routines,
which are TENEX-only runtimes.
7.2 - INITIALIZATION PHASES
______________ ______
User initializations are now done in successive phases, with all
initializations required for one phase being done before
initializations required for the next phase.
Syntax:
REQUIRE <procid> INITIALIZATION;
REQUIRE <procid> INITIALIZATION [<phase no>];
where <phase no> is an integer constant.
Semantics:
<phase no> specifies the number of the user initialization phase.
19
SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
If it is left out, then one is used. Currently, there are three
phases, numbered 0, 1, and 2. If the demand is great enough,
additional phases may be added later. (Note for assembly language
hackers: internally, user phases are numbered '400000, '400001, etc.)
7.3 - CHNCDB
______
val←CHNCDB(channel)
This integer procedure returns a pointer to the three word block used
to open the specified channel. It is provided for the benefit of
assembly language procedures that may want to do I/O inside some fast
inner loop, but which may want to live in a SAIL core image & use the
SAIL OPEN, etc.
This feature does not work in TENEX SAIL. See a hacker if you want
these features.
7.4 - ARRCLR
______
ARRCLR(arry)
This new runtime routine clears any kind of array. That is, arthmetic
arrays get filled with zeros, string arrays with NULLs, and itemvar
arrays with ANYs. One may use ARRCLR with set and list arrays, but
the set and list space will be lost (i.e. un-garbage-collectable).
The alternative form:
ARRCLR(arry,val)
where val is either an integer or a real number, will fill arry with
that value. Do not do this to string or list arrays unless you do
not care whether or not your program works. Also using a real val
for an itemvar array is apt to cause strange results. (If you use an
integer, arry will be filled with CVI(val).)
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SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
7.5 - SETPL
_____
SETPL(channel, @linnum, @pagnum, @sosnum)
This new runtime routine allows one to keep track of the string input
from CHANNEL. Whenever a '12 is encountered, LINNUM is incremented.
Whenever a '14 is encountered, PAGNUM is incremented, and LINNUM is
zeroed. Whenever an SOS line number is encountered, it is placed
into SOSNUM. When fully implemented (soon), this will work on the
INPUT, INTIN, and REALIN functions as well.
7.6 - EVALREDEFINE
____________
EVALREDEFINE bears the same relationship to REDEFINE as EVALDEFINE
does to DEFINE. See pages 47 and 50 of the Manual.
7.7 - CVPS
____
CVPS(<macro_parameter>) converts <macro_parameter> to a string and
returns the string. See about macro parameters on page 48 of the
manual.
7.8 - EXPRESSIONS IN REQUIRES
___________ __ ________
Previously, all REQUIRE constructs had to have only constants in
them. Now SAIL allows compile time expressions as well. See about
compile time expressions on page 47 of the Manual.
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SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
7.9 - RELEASE
_______
RELEASE now takes an optional second argument, the CLOSE inhibit
bits. These are described in the UUO manual (Stanford System). These
are defaulted to zero when not specified so that old programs which
did not specify them will work as before.
The CLOSE inhibit feature only works at SU-AI.
7.10 - TTYUP
_____
oldval←TTYUP(newval)
This routine casuse conversion of lower case characters (a-z) to
their upper case equivalents for strings read by any of the SAIL
teletype routines that do not use break tables. If newval is TRUE,
then conversion will take place on all subsequent inputs until TTYUP
is called with newval FALSE. Oldval will always get set to the value
of newval used in the previous call. (If TTYUP has never been called,
then no conversions will take place, and the first call to TTYUP will
return FALSE).
In TENEX, TTYUP sets the system parameter using the STPAR jsys to
convert to upper case.
7.11 - BREAKSET MODES "K" AND "F"
________ _____ ___ ___ ___
A "K" specification as a BREAKSET mode will cause lower to upper case
conversion when that break table is used. Conversion takes place
before each character is checked for breaking or omission. An "F"
specification turns off the conversion -- i.e. it undoes the effects
of "K".
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SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
7.12 - INOUT
_____
INOUT(inchan,outchan,howmany)
INOUT reads howmany words from channel inchan and writes them out on
channel outchan. Each channel must be open in a mode between 8 and
12. on return, the EOF variables for the two channels will be the
same as if ARRYIN & ARRYOUT had been used. If howmany is less than
zero, then transfer of data will cease only upon end of file or a
device error.
(note: INOUT uses BLTs to transfer data directly from one set of
buffers to the other)
INOUT is not available in TENEX SAIL.
7.13 - GETSTS & SETSTS
______ _ ______
SETSTS(chan,new_status)
issues a SETSTS uuo on channel chan with the status value new_status.
status←GETSTS(chan)
returns the results of a GETSTS uuo on channel chan.
These functions do not exist in TENEX SAIL. Instead, see GTSTS,
GDSTS, STSTS, and SDSTS for analogous features.
7.14 - CHANGES TO "OPEN" ERROR HANDLING
_______ __ ______ _____ ________
If the EOF variable supplied to OPEN is non-zero and the device name
is invalid, then OPEN will fail without giving the error message
"INVALID DEVICE NAME FOR OPEN", and the EOF value will be unchanged.
If a device is unavailable, and EOF=0, then the user is now given the
options of trying again or going on without opening the device, in
which case EOF will be set to non-zero as usual.
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SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
7.15 - ASH
___
ASH has been added as an arithmetic operator. Its syntax is just
like that of LSH, and it generates similar code (except for putting
out a PDP-10 ASH instruction instead of a LSH).
7.16 - ARG_LIST
________
ARG_LIST(<arg1>,...,<argn>)
where each <arg> may be any valid argument to the REF_ITEM construct,
assembles a list of "temporary" reference items that will be deleted
by APPLY after the applied procedure returns. Thus
APPLY(proc,ARG_LIST(foo,bar,VALUE baz))
is roughly equivalent to
tmplst←{{REF_ITEM(foo),REF_ITEM(bar),REF_ITEM(VALUE baz)}};
APPLY(proc,tmplst);
WHILE LENGTH(tmplst) DO DELETE(LOP(tmplst));
but is somewhat easier to type. Note that the reference items
created by ARG_LIST are just like those created by REF_ITEM, except
that they are marked so that APPLY will know to kill them.
7.17 - CLOSE
_____
The CLOSE function now has an additional optional argument that
allows the CLOSE inhibit bits to be turned on. The second argument
is the bit pattern for the inhibition, and it is defaulted 0. See
the UUO manual for details.
This feature is available only at SU-AI, and is not available in the
TENEX version of SAIL.
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SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
7.18 - TYPEIT
______
The number returned by the TYPEIT procedure (which identifies the
type of the datum of its item expression argument) is now changed for
arrays. Now it is '24 plus the scalar value of the type (e.g.,
INTEGER), whereas before it was '15 plus the scalar value.
Additional types added to TYPEIT are: '16 for labels, '17 for record
classes.
7.19 - COMPARISON OF .REL FILES
__________ __ ____ _____
Starting with version 18, the compiler emits information into each
.REL file containing the version of the compiler used. Then, during
the SAIL initialization sequence, these versions are compared, and a
warning message is issued if necessary. Thus, the problem of
converting from one version of the compiler to a new version is
lessened. This feature may not work as well in the current
changeover as it will in the future.
7.20 - SCAN Optimizations
____ _____________
The SCAN function has been modified to return true substrings instead
of copies in those cases that the break table in question was not
omitting any characters. This should be an improvement in the
efficiency of those routines.
7.21 - BREAK TABLES
_____ ______
There are now 54 user-setable break tables available to the SCAN,
INPUT, TTYINL functions, as well as SETBREAK and BREAKSET. These
tables are allocated and deallocated dynamically.
In addition, GETBREAK now returns the value of the smallest
unallocated breaktable, and RELBREAK releases its table argument.
The implicit declarations of these new runtime routines are:
INTEGER PROCEDURE GETBREAK
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SAIL Addendum 1 MISCELLANEOUS NEW FEATURES
PROCEDURE RELBREAK(INTEGER TABLE)
NOTE: a breaktable is allocated by either GETBREAK, SETBREAK,
BREAKSET or STDBRK. A breaktable is de-allocated (and thereby made
available to GETBREAK) by RELBREAK. Breaktables are stored in groups
of 18, so it is more efficient to use all the tables in a given group
before going to another group. The use of GETBREAK is particularly
recommended for load-modules and the like, so that conflicts will be
minimzed. Breaktable zero is special. It is predeclared to produce
the same results as SETBREAK(0,NULL,NULL,"I"). This results in
break-on-count for calls to INPUT, and always returns the whole
string for SCAN. Breaktable zero is stored along with breaktables 1
to 18, and thus takes up no additional space.
HACKERS: Actually there are 17 additional system breaktables which
are reserved for use by the SAIL runtime system. These tables are
numbers -17 through -1, and are ordinarily not available to the user.
They will be used by the debugger and by additional SAIL system
software.
The user can obtain access to breaktables -17 through -1 by setting
BRKPRV(USER) to -1, for example by the USERCON function which
accesses the SAIL user table. WARNING: absolutely no guarantees are
made to the user who accesses these breaktables. This information is
intended for completeness only; the use of these special breaktables
by the user is not recommended.
7.22 - TENEX RUNTIMES
_____ ________
The TENEX version of SAIL now has these additional teletype-oriented
routines: STTYP, GTTYP, STPAR, STI, and DELNF, all named after
jsyses. See TENEX-specific documentation.
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