.todo

= multiple sequence builder modifiers, e.g. index AND previous

= f(n) = n + f(n-1) + f(n-2), 1 1 3
'some-seq [  = ( -- sequence )
  0 1 [ + + ] [ with-previous with-index ] sequence
] def

= sequence word

'linear-sequence [
  1 [ 1 + ] sequence
] def

same as

'linear-sequence [  = ( -- sequence )
  [ 1 [ 1 + ] next ]
] def

= empty quote

1 ' curry puts = [ ]
fix: currently this fails:
' call
1 ' curry call

= currying

1 1 curry puts = [ 1 1 ]
should it be like that? doesn't curry expect a quote at the top of the stack?

= private by default - defined word is not exported from a namespace, unless explicitly made public

= namespace detection

```
[ file io ] use

1 puts     = `puts` comes from `io:` namespace
1 io:puts  = same
'script.l' file:read = have to specify the namespace, as both used namespaces export the `read` word
```

= namespace isolation

'sequence use
doesn't make exported words available outside of the file that uses it explicitly

= rework [1,b] et all to be lazy sequences

= introduce '? for doc/source: 'times ? / 'times show-source / 'times show-doc

= introduce 'first-n  as a specific filter: [ ... ] 5 first-n 'puts each

= data structures

'associative-list [
  [
    [ 'a 1 ]
    [ 'b 2 ]
    false
] def

'tree [
  [ [ 1 [ 4 false ] ] [ 2 [ 3 false ] ] ]
def

= replace debug with repl

implement 'stack for debug to print it

= file operations

nix: file:open file:read file:write file:close

= self-parser and self-interpreter, bootstrap

=== VMs and compilers

https://github.com/crcx/nga - no i/o, stack, simple, few instructions
https://c9x.me/compile/
http://microvm.github.io/ (dead)
www.vpri.org/pdf/tr2010003_PEG.pdf source->ast->pseudo->machine

=== natural speak

'a [ ] def

18 a prime? is


=== failures

3 [1,b] 5 nth

[ ] expect-error


=== types

number
quote
string
sequence

= meaningful errors

"a" 1 +
number head-tail


= type-specific methods?

1 circle area puts  = 3.14...
2 square area puts  = 4

= pmap

parallelize computation for non-dependent sequences

= effects

https://koka-lang.github.io/koka/doc/book.html#sec-handlers

'square-root ( positive-number -- root ) [ ... ] exception def
                                                 ^^^^^^^^^

also https://concatenative.org/wiki/revision/1184