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APL-20 PANDAMONIUM REIGNS!

APLSF (System Function) is an implementation of the APL programming language for TOPS-20 that is available on TWENEX.

In and Out

To start the APL interpreter, type the following from EXEC:

@APLSF

At the terminal.. prompt, enter tty for a non-APL keyboard.

Leave APLSF by entering one of the following commands (APLSF converts all alphabetic input to upper-case):

)MONTerminate APLSF and return to EXEC.
)OFFTerminate APLSF and log out of TWENEX.
)CONTINUESave active workspace to file DSK:CONTIN.APL, terminate APLSF, log-out from TWENEX. The saved workspace will be loaded automatically the next time you run APLSF.

To interrupt APLSF during execution, press Ctrl-C once or twice.

Press Ctrl-C five (5) times to suspend APLSF and return to EXEC. Resume APLSF with command @REENTER or @CONTINUE.

APL Character Set With ASCII and Escape Mode Equivalents

[For convenience, part of the keyboard mapping table from APLSF Language Manual is duplicated below.]

APL
Character
Name ASCII Escape
Mode
APL
Character
Name ASCII
and & Grade Down .GD
assignment _ Grade Up .GU
÷ divide % I-Beam (histogram) .IB
exponentiate * @E LoGarithm .LG
× multiply # NaNd .NN
? question (roll and deal) ? @Q NoR .NR
' quote string ' @K back expansion .CB
take ^ @Y (Circle) Rotate .CR
residue (ABsolute value) .AB @M back scan .CS
α ALpha .AL @A Divide Quad .DQ
quad (BoX) .BX @L Input Quad .IQ
CEiling (maximum) .CE @S Output Quad .OQ
drop (Down Arrow) .DA @U OUt .OU
¨ Dieresis .DD Protected Del .PD
DEcode .DE @B Quad Del .QD
DeL .DL @G Quad Quote .QQ
DiaMond .DM ReVersal .RV
Down Under .DU @C TRanspose .TR
ENcode .EN @N eXecute .XQ
EPsilon .EP @E ForMat .FM
FLoor .FL @D Comment (lamp)
Greater then or Equal to .GE A-Z underscored alphabetics .ZA-.ZZ
GO to (branch) .GO underscored lower del .Z@
IOta .IO @I
{ Left curly Brace .LB
delta (Lower Del) .LD @H
Less than or Equal to .LE
Left tacK .LK
circle (Large O) .LO @O
Left Union .LU @X
Not Equal to .NE
NeGation .NG
NoT .NT @T
OMega .OM @W
OR .OR
} Right curly Brace .RB
RhO .RO @R
Right tacK .RK
Right Union .RU @Z
jot (Small O) .SO @J
_ UnderScore .US @F
Up Union .UU @V

Function Editor

To define a new function and invoke the editor, enter one of the following commands:

.DL[r_]a1 f a2[;v]…Define a dyadic (two-argument) function
.DL[r_]f a1[;v]…Define a monadic (one-argument) function
.DL[r_]f[;v]…Define a niladic (no-argument) function

Where:

fFunction name
a1, a2Dummy arguments
rDummy variable for return value
vLocal variable

To edit an existing function, enter the command .DLf.

The editor will start and prompt with the current line number, for example [1].

Editor commands

textAdd text at current line.
[n]textReplace line n with text. Edit the function header as line 0.
[n.m]textInsert text as new line after line n. (Lines are automatically renumbered after each editing session.)
[.LDn]Delete line n.
[.BX]List function source.
[n.BX]List line n.
[.BXn]List from line n to the end of the function.
.DLSave function and return from editor.

Multiple commands can be entered on a single line. For an example, you can open the editor on existing function FUN1, list its source, and immediately exit the editor by entering the following command in the APL interpreter:

   .DLFUN1[.BX].DL

References

apl.1638514566.txt.gz · Last modified: 2021/12/03 06:56 by papa