path: root/ps/core.ps

% requires types.ps

% Errors/Exceptions

% data -> throw ->
% Takes arbitrary data and throws it as an exception.
/throw { 0 _nth _throw } def


% Hash Map functions

% [hashmap key val ...] -> assoc -> new_hashmap
/assoc { 4 dict begin
    /args exch def
    /src_dict args 0 _nth /data get def
    /new_dict src_dict
              dup length args _count 1 sub 2 idiv add % new length
              dict % new dict of that length
              copy def
    1 2 args _count 1 sub { %for each key idx
        /idx exch def
        new_dict  args idx _nth  args idx 1 add _nth  put
    } for
    new_dict _hash_map_from_dict
end } def

% [hashmap key...] -> dissoc -> new_hashmap
/dissoc { 4 dict begin
    /args exch def
    /src_dict args 0 _nth /data get def
    /new_dict src_dict dup length dict copy def
    1 1 args _count 1 sub { %for each key idx
        /idx exch def
        new_dict  args idx _nth  undef
    } for
    new_dict _hash_map_from_dict
end } def

% [hashmap key] -> hash_map_get -> value
/hash_map_get {
    dup 0 _nth % stack: args hash_map
    dup null eq { %if hash_map is a nil
        pop pop null
    }{ %else hash_map is not a nil
        /data get % stack: args dict
        exch 1 _nth % stack: dict key
        2 copy known { %if has key
            get
        }{
            pop pop null
        } ifelse
    } ifelse
} def

% [hashmap key] -> contains? -> bool
/contains? {
    dup 0 _nth /data get % stack: args dict
    exch 1 _nth % stack: dict key
    known
} def

% [hashmap] -> keys -> key_list
/keys {
    0 _nth /data get
    [ exch { pop dup length string cvs } forall ]
    _list_from_array
} def

% [hashmap] -> vals -> val_list
/vals {
    0 _nth /data get
    [ exch { exch pop } forall ]
    _list_from_array
} def


% sequence functions

% [obj list] -> cons -> new_list
/cons { 3 dict begin
    /args exch def
    /elem args 0 _nth def
    /lst args 1 _nth def
    lst _count 1 add array
    dup 0 elem put % first element
    dup 1 lst /data get putinterval % rest of the elements
    _list_from_array
end } def

% [listA listB] -> do_concat -> [listA... listB...]
/do_concat {
    dup _count 0 eq { %if just concat
        pop 0 _list
    }{ dup _count 1 eq { %elseif concat of single item
        0 _nth % noop
    }{ % else
        [] exch
        /data get {
            /data get concatenate
        } forall
        _list_from_array
    } ifelse } ifelse
} def

% [obj] -> do_count -> number
/do_count {
    0 _nth dup _nil? {
        pop 0
    }{
        _count
    } ifelse
} def

% [obj ...] -> first -> obj
/first {
    0 _nth _first
} def

% [obj objs...] -> first -> [objs..]
/rest {
    0 _nth _rest
} def

% [vect elem...] -> conj -> new_vect
% [list elem...] -> conj -> new_list
/conj { 5 dict begin
    /args exch def
    /src_arr args 0 _nth /data get def
    /new_len src_arr length   args _count 1 sub   add def
    /new_arr new_len array def
    args 0 _nth _list? { %if list
        new_arr   new_len src_arr length sub   src_arr putinterval
        args _count 1 sub -1 1 {
            /idx exch def
            new_arr   args _count idx sub 1 sub   args idx _nth   put
        } for
        new_arr _list_from_array
    }{ %else vector
        src_arr new_arr copy pop
        1 1 args _count 1 sub {
            /idx exch def
            new_arr   src_arr length idx add 1 sub   args idx _nth   put
        } for
        new_arr _vector_from_array
    } ifelse
end } def

% [function args... arg_list] -> apply -> result
/apply { 1 dict begin
    /args exch def
    args 0 _nth callable % make sure function is callable
    args /data get 1 args _count 2 sub getinterval % get args slice
    args args _count 1 sub _nth /data get % get arg_list array
    concatenate _list_from_array exch % stack: args function
    exec
end } def

% [function list] -> _map -> new_list
/map { 1 dict begin
    dup 0 _nth exch 1 _nth % stack: function list
    /args exch def
    callable % make sure function is callable
    %/new_list args length array def
    args /data get { %foreach arg
        1 array astore _list_from_array % stack: fn arglist
        exch dup 3 1 roll               % stack: fn arglist fn
        exec exch % stack: result fn
    } forall 
    pop % remove the function
    args _count array astore
    _list_from_array
end } def


% Metadata functions

% [obj meta] -> with_meta -> new_obj
/with_meta {
    dup 1 _nth exch 0 _nth % stack: meta obj
    dup length dict copy   % stack: meta new_obj
    dup 3 -1 roll          % stack: new_obj new_obj meta
    /meta exch put
} def

% [obj] -> meta -> meta
/meta {
    0 _nth % stack: obj
    dup type /dicttype eq { %if dictionary
        dup /meta known { /meta get }{ pop null } ifelse
    }{ %else
        pop null % no meta on non-collections
    } ifelse
} def


% Atom functions

/deref {
    0 _nth /data get
} def

% [atm val] -> reset! -> val
/reset! {
    dup 0 _nth exch 1 _nth % stack: atm val
    dup 3 1 roll           % stack: val atm val
    /data exch put
} def

% [atm f args...] -> swap! -> new_val
/swap! { 3 dict begin
    /args exch def
    /atm args 0 _nth def
    [ atm /data get ] 
    args 2 args _count 2 sub _slice /data get
    concatenate _list_from_array
    args 1 _nth callable % extract proc
    exec
    /new_val exch def
    atm /data new_val put
    new_val
end } def


% core_ns is namespace of core functions

/core_ns <<
    (=)       { dup 0 _nth exch 1 _nth _equal? }
    (throw)   { throw }
    (nil?)    { 0 _nth _nil? }
    (true?)   { 0 _nth _true? }
    (false?)  { 0 _nth _false? }
    (symbol)  { 0 _nth _symbol }
    (symbol?) { 0 _nth _symbol? }
    (keyword) { 0 _nth _keyword }
    (keyword?) { 0 _nth _keyword? }

    (pr-str)  { /data get ( ) true _pr_str_args }
    (str)     { /data get () false _pr_str_args }
    (prn)     { /data get ( ) true _pr_str_args print (\n) print null }
    (println) { /data get ( ) false _pr_str_args print (\n) print null }
    (readline) { 0 _nth _readline not { pop null } if }
    (read-string) { 0 _nth read_str }
    (slurp)   { 0 _nth (r) file dup bytesavailable string readstring pop }
    (<)       { dup 0 _nth exch 1 _nth lt }
    (<=)      { dup 0 _nth exch 1 _nth le }
    (>)       { dup 0 _nth exch 1 _nth gt }
    (>=)      { dup 0 _nth exch 1 _nth ge }
    (+)       { dup 0 _nth exch 1 _nth add }
    (-)       { dup 0 _nth exch 1 _nth sub }
    (*)       { dup 0 _nth exch 1 _nth mul }
    (/)       { dup 0 _nth exch 1 _nth idiv }
    (time-ms) { pop realtime }

    (list)    { /data get _list_from_array }
    (list?)   { 0 _nth _list? }
    (vector)  { /data get _vector_from_array }
    (vector?) { 0 _nth _vector? }
    (hash-map) { /data get _hash_map_from_array }
    (map?)    { 0 _nth _hash_map? }
    (assoc)   { assoc }
    (dissoc)  { dissoc }
    (get)     { hash_map_get }
    (contains?) { contains? }
    (keys)    { keys }
    (vals)    { vals }

    (sequential?) { 0 _nth _sequential? }
    (cons)    { cons }
    (concat)  { do_concat }
    (nth)     { dup 0 _nth exch 1 _nth _nth }
    (first)   { first }
    (rest)    { rest }
    (empty?)  { 0 _nth _count 0 eq }
    (count)   { do_count }
    (conj)    { conj }
    (apply)   { apply }
    (map)     { map }

    (with-meta) { with_meta }
    (meta)    { meta }
    (atom)    { 0 _nth _atom }
    (atom?)   { 0 _nth _atom? }
    (deref)   { deref }
    (reset!)  { reset! }
    (swap!)   { swap! }
>> def