this document refers to the version of apl\11 that comes with 211bsd

uncompress apl.tar.Z in /usr/src/new/PORT/apl
tar -xvf apl.tar

ai.c was updated to use vi

apl\11 employs 1-origin indexing

apl\11 was originally written by Ken Thompson
and enhanced by Purdue University

211bsd.sh invokes 211bsd via simh

man apl          documentation on the apl interpreter

apl              invoke apl (probably better not to use -m option)

apl < quick      load quick
                 note that any series of apl statements can be
                 put in a text file, the apl executable processes
                 all lines then exits

)clear
)load mark1
)save mark1
)off
)digits 9        specifies that 9 digits are displayed
)origin 1        set origin to 1 (other values are also possible)
)width 80        set characters per line to 80
)vars            list all variables
)fns             list all functions
)drop mark1      delete mark1
)shell           drops to bash shell
)prws            print contents of workspace in readable form
)read say        read function say (stored in ascii as file say)
)list say        list function say
)script file     everything typed in the apl environment is written to file

Lrun 'ls'        runs commands such as ls
Lcr say          execute function say
Lnc 'x'          determines what type of variable x is:
                  0 means variable is undefined
                  2 means variable is a label or variable
                  3 means variable is a function type 

5*2      returns 25
5X3      returns 15
4%10     returns .4 (4 divided by 10)

%2       returns the reciprocal of 2

5 10 15 X 2
         multiply a series of numbers by 2

v { 1 2 3 4 5
+/ v     sum all elements of v
+\ v     returns running sum across v
X/ v     product all elements of v
X\ v     returns running product across v
!v       returns factorial of all elements of v
v[1,2]   returns elements 1 and 2
O1       returns pi times 1
!5       returns factorial of 5
!3.5     returns 11.6317284 (fractional factorials are permitted)
`5       returns negative 5
|`5      returns absolute value of negative 5
2*.5     returns square root of 2
2 ! 4    choose 2 from 4, i.e. 6

1 ^ 1    1 and 1 returns 1
1 V 0    1 or 0 returns 1

3 $ 4    3 is less than or equal to 4, returns 1

I5       returns interval 5, e.g. 1 2 3 4 5

'b' > 'a'
         returns 1 (true)
1 # 2    1 not equal 2 returns 1

' ' = 'this is it'
         returns 0 0 0 0 1 0 0 1 0 0

v { 1 2 3 4 5
O^H| v   reverses v 
v[1 2 3] returns first 3 elements of v
v[] { 3  set all elements to 3

a { a,6  append 6 to a

5D7      returns 5 (min)
5S7      returns 7 (max)

a { 3 3 R I9
,a       returns 1 2 3 4 5 6 7 8 9

1O1      returns sin at 1
2O1      returns cos at 1

a { 7; b { 8; c { 9
         multiple statements on one line

'cat' E 'hat'
         returns 0 1 1

24 60 60 B 1 7
         returns 4020 (total seconds in one hour and 7 minutes)

8 8 8 B 1 2 3
         converts octal number 123 to decimal (83)

a { 3 3 R I9
\^HO a   transpose x and y elements of a 
          1 4 7
          2 5 8
          3 6 9

1.25e5   returns 125000

?3       returns random number from 1 to 3

a { 1 2 3
b { 3 4 5
a J.* b  returns outer product * (exponent)
   1   1   1
   8  16  32
  27  81 243
a J.+ b  returns outer product + (plus)
         note that J.= and J.> and J.< are also possible

a +.* b  returns 260 (inner product, not sure what this does)

v { I10
v J.X v  returns ten times table (multiply)
+/ , v J.X v 
         sum the ten times table

v { I5
v J.- v  returns all elements of v subtracted from all elements of v

a { 2 2 R I4
L^H% a   returns matrix inverse of a

a { 3 5 0 7 8 12 1
a[ |^HH a ]
         returns 0 1 3 5 7 8 12
         note that grade up must be typed as | ctrl-H H

1&1      1 is greater than or equal to 1, returns 1

0 Lopen 'manual'
         read file manual (returns file handle 4)
Lrd 4    read one line from file handle 4
4 Lread 20
         read 20 bytes from file handle 4

v { L^H'
         v is assigned with user input (L^H means quotequad)

x { 3
'x is ',N^HJ x

c { 'catbat'
'b' E c  is b an element of c, returns 1

B^HJ 'v { 1 2 3'
         executes string

B^HN 20  example of an ibeam, generally B ctrl-H N followed by a number
         in this case it returns the total number of 1/60 sec intervals since midnight
B^HN 28  returns the date
B^HN 29  returns the origin 
B^HN 32  returns number of workspace bytes in use

replacement characters
----------------------

$ for less than or equal to
& for greater than or equal to
` for negative sign
~ for not
% for reciprocal
# for not equal
^ for and
V for or
C for comment
R for rho
E for epsilon
Y for take (up arrow)
U for drop (down arrow)
D for min (floor)
S for max (ceiling)
N for encode
B for decode
M for multiply
L for quad (denotes start of a function)

limitations
-----------

no nested arrays

I've recompiled apl to use vi as the editor but there's a problem with 
any operator of the form A ^H B in that you can't type that sequence
into vi and expect apl to process it correctly. One must use the
)script command and create any lines with these operators then read
them into the appropriate part of the file.

using plain ed works too :)