apl\11 1977 runs under Unix version 6 and 7

note that in most versions of apl that the shape of a vector of one element
is null and this can not be used in mathematical expressions

feb 1977 version
----------------

precompiled binary is used, we are not able to compile it as yet
separate executable works (unlike oct 1976 version which core dumps on edit)

labels are supported

comments inside functions must occur after function definition (first line)
no blank lines in functions

stty erase ^H  do not use

avoid hitting backspace

use M instead of X for multiply
use P instead of % for divide

L^HP a    returns matrix inverse of a (ctrl-H is not echoed to screen) 

)clear         clears workspace
)width 80      set characters per line to 80
)vars          list all variables
)fns           list all functions
)edit test     edit function test (this also puts function test in memory)
               note that for this version )edit invokes xed
               
)erase file    erase function file from workspace
)drop file     erase file

E 'v { 1 2 3'  execute string, e.g. v is set to 1 2 3
               epilson will not work as execute on IBM APL2

1 V 0          1 or 0 returns 1

1 /^H= 2       1 not equal 2 returns 1

x { 2
'x = '; x      displays x= 2

a { 2; b { 3; c { 4
               multiple statements on one line are separated by semi-colons
'this is a ';a;' and b '; b
               displays this is a  2 and b  3

a { 'cat'      variables can be strings of characters

'APPLE'[3]     returns 3rd character of APPLE, .e.g P

a { 'apple'
b { 'string'
c { a,' ',b    assign c the value of a and b with a space inbetween
               e.g. c is 'apple string'

a { (I10) M .5
               same as a=1 to 10 step .5

!3.5     returns 11.6317284 (fractional factorials are permitted)
2 ! 4    choose 2 from 4, i.e. 6 (also known as binomial coefficient)
             
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 21  ???
B^HN 24  ???
B^HN 25  ???
B^HN 28  returns date
B^HN 29  returns origin
B^HN 30  returns width

x { L          enter numeric data (L is quad)
'test'; x { L  prompts must appear on the same line as quad to work

functions
---------

average v      find average of a vector
boxit 'test'   display a box around test
factors v      find all factors of vector
fib n          generate n terms fibonacci series (modified to work with apl-1977)
gcd            find the greatest common divisor, e.g. 70 gcd 10
ident          generate the identity matrix
inverse a      find matrix inverse of a where a is a matrix
matrix a       display a matrix a X a of counting numbers
multi a        generate multiplication table of a X a (will core dump if array is too big)
matrixab a b   generates matrix of counting numbers a by b
prime          works but core dumps if values higher than 70 are used
primen n       display prime numbers up to n
rising         compute the rising factorial

primei         does not work, returns  "compress index" 
fib1           does not work, returns  "fetch botch"

doesn't have
------------

Lrun
Lcr 
)shell
)list

xed notes
---------

pp	       print out entire file
f              display current filename
x              undelete last deletion

oct 1976 version
----------------

must be compiled as a pure executable to work properly

labels are not supported, line numbers must be used instead

}clear         clear workspace   } represents right parentheses
}drop file     erase file 
}edit test     edit function test (this also puts function test in memory)
               note that for this version }edit invokes ed

}erase a       erase variable or function a
}fns           list functions
}lib           list files in current directory
}vars          list variables
}width 112     set width to 112

}off           log out

C for comment
R for rho
E for epsilon
D for min (floor)
S for max (ceiling)
Y for take (up arrow)
U for drop (down arrow)
M for absolute value or modulus

; is [
] is ]
* is -
< is ;
> is :
- is multiply
: is plus
" is minus sign
= is divide
P is power 
+ is (
} is )
% is =
[ is assign

{3             goto line 3 (the first line after the function header is line 1)

+1:1} - 5      this is equivalent to (1+1) X 5

:/ I10         sum the numbers 1 through 10

a [ 1 2 3      assign 1 2 3 to a

a [ KappleK    assign apple to a

a [ I10
a J.- a        generate multiplication table

b [ a J.- a
:/ ,b          sum matrix b

3Y a           take first 3 elements of vector a

a,b            concatenate a and b

1 ( 2          1 not equal 2 returns true or 1

-/I5           returns 5 factorial

0 )T 0         0 NOR 0 returns 1

"5 : 1         negative 5 plus 1 returns 4
M "5           return absolute value of negative 5

3Q10           return 3 random numbers from 1 to 10

K^H. 5         return 5 factorial or 120

2 K^H. 5       choose 2 from 5 or 10 (also known as binomial coefficient)
               this was put into function comb

a [ 1 2 3
O^HM a         rotate vector a

a [ 2 2 R I4
L^H= a         return matrix inverse of a

E K x [ 1 K    execute x=1

N^HB 29        return origin, B^HN 29 will also work (ibeam)

functions
---------

comb           find the binomial coefficient, e.g. 2 comb 5 returns 10
fac x          find the factorial of x
gcd            find the greatest common divisor, e.g. 70 gcd 10
loopit x       print apple x times
matrixab       generates matrix of counting numbers
sum            sum a vector of numbers

a [ loopit x
a [ x
C loopit x times
{+x$0}/0
c[0
c[c:1
{+c%x:1}/0
L [ K apple K
{5