(with_import "./collections.kp"
(let (
    ; This partial eval only works via the root env,
    ; since we can't tell from outside if something takes an env
    ; or not
    ; Also, based on that, we have to switch on every primitive...


    ; Here is every form in k'
    ; True
    ; False
    ; Env: *KPEnv
    ; Combiner: KPCombiner / BuiltinCombiner: KPBuiltinCombiner
    ; String: str
    ; Symbol: str
    ; Int: int
    ; Array: rc<vec<KPValue>>
    ; Nil


    ; Ok, some more things we need / need to change

    ; Arrays need to be able to contain some combination of now and later that 
    ; can be extracted correctly by the relevent operators (idx, slice)

    ; Vau needs to be handled, obv, which will require a handling of it
    ; pre-evaluating the parameters. The more I think about it, the more
    ; straight forward it seems actually - it can mostly mirror actual vau?

    ; how should empty-env be handled? More generally, how much do we reify enviornments?

    ; meta...

    ; I think now/later will have to be split into
    ; later/now_value/array/comb(wrap_level / dynamic_env_usage?)/env
    ; Env will need special checking for escaping, including when contained inside of an array or other combinator
    ; Actually, that extends to checking escaping for combinators in general, since they may close over laters


    now? (lambda (x) (= 'now (idx x 0)))
    val  (lambda (x) (idx x 1))
    partial_eval_helper (rec-lambda recurse (x env)
        (cond   (= x true)                      ['now true ]
                (= x false)                     ['now false]
                (env? x)                        (error "called partial_eval with an env " x)
                (combiner? x)                   (error "called partial_eval with a combiner, not yet supported (assuming just parsed symbols etc) " x)
                (string? x)                     ['now x]
                (symbol? x)                     (get-value env x)
                (int? x)                        ['now x]
                (and (array? x) (= 0 (len x)))  (error "Partial eval on empty array")
                (array? x)                      (let (
                                                    subs (map (lambda (y) (recurse y env)) x)
                                                    comb (idx subs 0)
                                                ) (if (now? comb) ((val comb) (slice subs 1 -1))
                                                                  ['later (map val subs)]))
                (nil? x)                        ['now x]

        )
    )
    needs_params_real (vau de (f_sym) ['now (lambda (params) (if (foldl (lambda (a x) (and a (now? x))) true params) ['now (lapply (eval f_sym de) (map val params))]
                                                                                                                     ['later (cons f_sym (map val params))])) ])
    partial_eval (lambda (x) (partial_eval_helper x [
        ; vau
        ; eval
        ; cond
        [ 'symbol? (needs_params_real symbol?) ]
        [ 'int? (needs_params_real int?) ]
        [ 'string? (needs_params_real string?) ]
        ; combiner?
        ; env?
        [ 'nil? (needs_params_real nil?) ]
        [ 'bool? (needs_params_real bool?) ]
        ; array?
        [ 'str-to-symbol (needs_params_real str-to-symbol) ]
        [ 'get-text (needs_params_real get-text) ]
        ; array
        ; len
        ; idx
        ; slice
        ; concat
        [ '+ (needs_params_real +) ]
        [ '- (needs_params_real -) ] 
        [ '* (needs_params_real *) ] 
        [ '/ (needs_params_real /) ] 
        [ '% (needs_params_real %) ] 
        [ '& (needs_params_real &) ] 
        [ '| (needs_params_real |) ] 
        [ '<< (needs_params_real <<) ]
        [ '>> (needs_params_real >>) ]
        [ '= (needs_params_real =) ]
        [ '!= (needs_params_real !=) ]
        [ '< (needs_params_real <) ]
        [ '<= (needs_params_real <=) ]
        [ '> (needs_params_real >) ]
        [ '>= (needs_params_real >=) ]

        ; Don't forget, these short-circut with the truthy/falsey values
        ; and
        ; or

        ; pr-str
        [ 'str (needs_params_real str) ]
        [ 'prn (needs_params_real prn) ]
        ; println
        ; meta
        ; with-meta
        ; wrap
        ; unwrap
        ; error
        ; recover
        ; read-string
        ; slurp
        ; get_line
        ; write_file
        ; empty_env
    ]))
)
    (provide partial_eval now? val)
))