Shakti (k9) tutorial


k9: Manual

This manual is for Shakti (k9) build 2021.10.21.

The Shakti programming language is the work of Arthur Whitney and the team at Shakti. The language comes from a lineage of similar languages going back to APL. It’s also known as k9 given the similarities to k, k2, ..., k6, k7 and the fact that Arthur also wrote those. k9 is still under development so expect a bit of syntax change and likely even more improvements.

Learning k9 means code like {x@(!#x)+\!#y} is clear and actually prefered to something much longer and verbose. You’ll have to go a bit down the rabbit hole before it starts to come together but once it does you’ll probably be happy you gave it a chance and end up learning a few things. You’ll understand how fast k9 can be in processing and analyzing data and how terse code is less likely to contain errors. Unfortunately you will be less likely to be content using more bloated and slow frameworks.

Alas this manual is not as elegant as the k9 language in that the text version of this document is almost as big as the binary of the language.

The built-in reference screen (\) containing all the k9 commands.

python: import k;k.k('2+3')
nodejs: require('k').k('2+3')

$k [-n4 -p1024] a.k

t:[[]t:09:30:00.000 09:30:00.001;e:"b";s:`aa`aa;v:2 3;p:2.3 3.4]
`csv?`csv t     /also `json?`json t
`lz4?`lz4 x     /also `zstd?`zstd x

verb                    adverb                 noun                    \l a.k
: x         y          f' each                 char " ab"              \t:n x
flip      plus    [x]f/ over      c/ join    name ``ab               \u:n x
minus     minus   [x]f\ scan      c\ split   int  2 3                \v
first     times   [y]f':eachprior            flt  2 3.4              \w
%           divide     f/:eachright g/:over    date 2021.06.28   .z.d  
where     min/and    f\:eachleft  g\:scan    time 12:34:56.789 .z.t
reverse   max/or     
asc       less       i/o (*enterprise)       class
desc      more       0: r/w line             list (2;3.4;`c)
group     equal      1: r/w char             dict [n:`b;i:2]
not       match     *2: r/w data             func {[a;b]a+b}
key       key       *3: k-ipc set            expr :a+b
enlist    cat       *4: https get            
sort   [f]cut        5: ffi/import
# count  [f]take      
floor  [f]drop
string    parse      $[b;t;f] cond
unique    find/rand                               
type   [f]at         @[x;i;f[;y]] amend      table [[]n:`b`c;i:2 3]
value  [f]dot        .[x;i;f[;y]] dmend     utable  [[n:`b`c]i:2 3]

count  first last min max sum avg var dev [med ..]
select A by B from T where Cupdate A from T; delete from T where C
sqrt sqr exp log sin cos div mod bar in bin

/comment \trace [:return 'signal if do while]