*CPU
- A global variable holding the target CPU (architecture). Typical values are
"aarch64", "x86-64" etc. See also *OS and version.
: *CPU
-> "x86-64"
*Class
- A global variable holding the current class. See also OO Concepts,
class, extend, dm and var and rel.
: (class +Test)
-> +Test
: *Class
-> +Test
(cache 'var 'any [. prg]) -> any
- Speeds up some calculations by maintaining a tree of previously calculated
results in an
idx structure
("memoization") in var. A hash of the argument any is used
internally to build the index key. If no prg is given, the internal
var holding a previously stored value is returned (note that
var may have a name which is not human-readable).
: (de fibonacci (N)
(cache '(NIL) N
(if (>= 2 N)
1
(+ (fibonacci (dec N)) (fibonacci (- N 2))) ) ) )
-> fibonacci
: (fibonacci 22)
-> 17711
: (fibonacci 10000)
-> 3364476487643178326662161200510754331030 ... # (2090 digits)
: (off C)
-> NIL
: (cache 'C 1234 (* 3 4))
-> 12
: (inc (cache 'C 1234))
-> 13
: (val (cache 'C 1234))
-> 13
(call 'any ..) -> flg
- Calls an external system command. The
any arguments specify the
command and its arguments. Returns T if the command was executed
successfully. The (system dependent) exit status code of the child process is
stored in the global variable @@. See
also exec.
: (when (call 'test "-r" "file.l") # Test if file exists and is readable
(load "file.l") # Load it
(call 'rm "file.l") ) # Remove it
: (cons (call "sh" "-c" "kill -SEGV $$") @@ (hex @@))
-> (NIL 11 . "B")
call/1
- Pilog predicate that succeeds if the argument
term can be proven.
: (be mapcar (@ NIL NIL))
-> mapcar
: (be mapcar (@P (@X . @L) (@Y . @M))
(call @P @X @Y) # Call the given predicate
(mapcar @P @L @M) )
-> mapcar
: (? (mapcar permute ((a b c) (d e f)) @X))
@X=((a b c) (d e f))
@X=((a b c) (d f e))
@X=((a b c) (e d f))
...
@X=((a c b) (d e f))
@X=((a c b) (d f e))
@X=((a c b) (e d f))
...
(can 'msg) -> lst
- (Debug mode only) Returns a list of all classes that accept the message
msg. See also OO Concepts, class, has, dep, what and who.
: (can 'zap>)
-> ((zap> . +relation) (zap> . +Blob) (zap> . +Entity))
: (more @ pp)
(dm (zap> . +relation) (Obj Val))
(dm (zap> . +Blob) (Obj Val)
(and
Val
(call 'rm "-f" (blob Obj (: var))) ) )
(dm (zap> . +Entity) NIL
(for X (getl This)
(let V (or (atom X) (pop 'X))
(and (meta This X) (zap> @ This V)) ) ) )
-> NIL
(car 'var) -> any
- List access: Returns the value of
var if it is a symbol, or the
first element if it is a list. See also cdr and c..r.
: (car (1 2 3 4 5 6))
-> 1
-
(c[ad]*ar 'var) -> any
(c[ad]*dr 'lst) -> any
- List access shortcuts. Combinations of the
car and cdr functions, with up to four letters 'a' and
'd'.
: (cdar '((1 . 2) . 3))
-> 2
(case 'any (any1 . prg1) (any2 . prg2) ..) -> any
- Multi-way branch:
any is evaluated and compared to the CAR
elements anyN of each clause. If one of them is a list,
any is in turn compared to all elements of that list.
T is a catch-all for any value. If a comparison succeeds,
prgN is executed, and the result returned. Otherwise
NIL is returned. See also casq and state .
: (case (char 66) ("A" (+ 1 2 3)) (("B" "C") "Bambi") ("D" (* 1 2 3)))
-> "Bambi"
: (case 'b (a 1) ("b" 2) (b 3) (c 4))
-> 2
(casq 'any (any1 . prg1) (any2 . prg2) ..) -> any
- Multi-way branch:
any is evaluated and compared to the CAR
elements anyN of each clause. == is used for comparison (pointer equality). If
one of them is a list, any is in turn compared to all elements of
that list. T is a catch-all for any value. If a comparison
succeeds, prgN is executed, and the result returned. Otherwise
NIL is returned. See also case and state.
: (casq 'b (a 1) ("b" 2) (b 3) (c 4))
-> 3
: (casq 'b (a 1) ("b" 2) ((a b c) 3) (c 4))
-> 3
(catch 'any . prg) -> any
- Sets up the environment for a non-local jump which may be caused by
throw or by a runtime error. If
any is an atom, it is used by throw as a jump label
(with T being a catch-all for any label), and a throw
called during the execution of prg will immediately return the
thrown value. Otherwise, any should be a list of strings, to catch
any error whose message contains one of these strings, and this will immediately
return the matching string. If neither throw nor an error occurs,
the result of prg is returned. See also finally, quit and
Error Handling.
: (catch 'OK (println 1) (throw 'OK 999) (println 2))
1
-> 999
: (catch '("No such file") (in "doesntExist" (foo)))
-> "No such file"
(cd 'any) -> sym
- Changes the current directory to
any. The old directory is
returned on success, otherwise NIL. See also chdir, dir and pwd.
: (when (cd "lib")
(println (length (dir)))
(cd @) )
99
(cdr 'lst) -> any
- List access: Returns all but the first element of
lst. See also
car and c..r.
: (cdr (1 2 3 4 5 6))
-> (2 3 4 5 6)
(center 'cnt|lst 'any ..) -> sym
- Returns a transient symbol with all
any arguments packed in a centered format. Trailing blanks
are omitted. See also align, tab and wrap.
: (center 4 12)
-> " 12"
: (center 4 "a")
-> " a"
: (center 7 "a")
-> " a"
: (center (3 3 3) "a" "b" "c")
-> " a b c"
(chain 'any ..) -> any
- Concatenates (destructively) one or several new list elements
any to the end of the list in the current make environment. This operation is efficient
also for long lists, because a pointer to the last element of the result list is
maintained. chain returns the last linked argument. See also
link, yoke and made.
: (make (chain (list 1 2 3) NIL (cons 4)) (chain (list 5 6)))
-> (1 2 3 4 5 6)
(char) -> sym
(char 'cnt) -> sym
(char T) -> sym
(char 'sym) -> cnt
- When called without arguments, the next character from the current input
stream is returned as a single-character transient symbol, or
NIL
upon end of file. When called with a number cnt, a character with
the corresponding unicode value is returned. As a special case, T
is accepted to produce a byte value greater than any first byte in a UTF-8
character (used as a top value in comparisons). Otherwise, when called with a
symbol sym, the numeric unicode value of the first character of the
name of that symbol is returned. See also peek, skip, key, line, till and eof.
: (char) # Read character from console
A # (typed 'A' and a space/return)
-> "A"
: (char 100) # Convert unicode to symbol
-> "d"
: (char "d") # Convert symbol to unicode
-> 100
: (char T) # Special case
-> # (not printable)
: (char 0)
-> NIL
: (char NIL)
-> 0
(chdir 'any . prg) -> any
- Changes the current directory to
any with cd during the execution of prg. Then
the previous directory will be restored and the result of prg
returned. See also dir and pwd.
: (pwd)
-> "/usr/abu/pico"
: (chdir "src" (pwd))
-> "/usr/abu/pico/src"
: (pwd)
-> "/usr/abu/pico"
(chkTree 'sym ['fun]) -> num
- Checks a database tree node (and recursively all sub-nodes) for consistency.
Returns the total number of nodes checked. Optionally,
fun is
called with the key and value of each node, and should return NIL
for failure. See also tree and
root.
: (show *DB '+Item)
{40} 6
nr (6 . {H1})
pr (6 . {H3})
sup (6 . {H2})
nm (67 . {I3})
-> {40}
: (chkTree '{H1}) # Check that node
-> 6
(chop 'any) -> lst
- Returns
any as a list of single-character strings. If
any is NIL or a symbol with no name, NIL
is returned. A list argument is returned unchanged.
: (chop 'car)
-> ("c" "a" "r")
: (chop "Hello")
-> ("H" "e" "l" "l" "o")
(circ 'any ..) -> lst
- Produces a circular list of all
any arguments by consing them to a list and then connecting the
CDR of the last cell to the first cell. See also circ? and list.
: (circ 'a 'b 'c)
-> (a b c .)
(circ? 'any) -> any
- Returns the circular list tail if
any is a circular list, else
NIL. See also circ.
: (circ? 'a)
-> NIL
: (circ? (1 2 3))
-> NIL
: (circ? (1 . (2 3 .)))
-> (2 3 .)
(class sym . typ) -> obj
- Defines
sym as a class with the superclass(es)
typ. As a side effect, the global variable *Class is set to obj. See also
extend, dm, var,
rel, type, isa and object.
: (class +A +B +C +D)
-> +A
: +A
-> (+B +C +D)
: (dm foo> (X) (bar X))
-> foo>
: +A
-> ((foo> (X) (bar X)) +B +C +D)
(clause '(sym . any)) -> sym
- Declares a Pilog fact or rule for the
sym argument, by concatenating the any argument to the
T property of sym. See also *Rule and be.
: (clause '(likes (John Mary)))
-> likes
: (clause '(likes (John @X) (likes @X wine) (likes @X food)))
-> likes
: (? (likes @X @Y))
@X=John @Y=Mary
-> NIL
clause/2
- Pilog predicate that succeeds if the first
argument is a predicate which has the second argument defined as a clause.
: (? (clause append ((NIL @X @X))))
-> T
: (? (clause append @C))
@C=((NIL @X @X))
@C=(((@A . @X) @Y (@A . @Z)) (append @X @Y @Z))
-> NIL
(clip 'lst) -> lst
- Returns a copy of
lst with all whitespace characters or
NIL elements removed from both sides. See also trim.
: (clip '(NIL 1 NIL 2 NIL))
-> (1 NIL 2)
: (clip '(" " a " " b " "))
-> (a " " b)
(close 'cnt) -> cnt | NIL
- Closes a file descriptor
cnt, and returns it when successful.
Should not be called inside an out body
for that descriptor. See also open,
poll,
listen and connect.
: (close 2) # Close standard error
-> 2
(cmd ['any]) -> sym
- When called without an argument, the name of the command that invoked the
picolisp interpreter is returned. Otherwise, the command name is set to
any. Setting the name may not work on some operating systems. Note
that the new name must not be longer than the original one. See also argv, file and Invocation.
$ pil +
: (cmd)
-> "/usr/bin/picolisp"
: (cmd "!/bin/picolust")
-> "!/bin/picolust"
: (cmd)
-> "!/bin/picolust"
(cnt 'fun 'lst ..) -> cnt
- Applies
fun to each element of lst. When
additional lst arguments are given, their elements are also passed
to fun. Returns the count of non-NIL values returned
from fun.
: (cnt cdr '((1 . T) (2) (3 4) (5)))
-> 2
(collect 'sym 'cls ['hook] ['any|beg ['end [sym|cnt ..]]])
- Returns a list of all database objects of class
cls, where the
values for the sym arguments correspond to the any
arguments, or where the values for the sym arguments are in the
range beg .. end. sym, cls
and hook should specify a tree for cls or one of its
superclasses. If additional sym|cnt arguments are given, the final
values for the result list are obtained by applying the get algorithm. See also db, aux,
fetch, init, step and and search.
: (collect 'nr '+Item)
-> ({B1} {B2} {B3} {B4} {B5} {B6} {B8})
: (collect 'nr '+Item 3 6 'nr)
-> (3 4 5 6)
: (collect 'nr '+Item 3 6 'nm)
-> ("Auxiliary Construction" "Enhancement Additive" "Metal Fittings" "Gadget Appliance")
: (collect 'nm '+Item "Main Part")
-> ({B1})
(commit ['any] [exe1] [exe2]) -> T
- Closes a transaction, by writing all new or modified external symbols to,
and removing all deleted external symbols from the database. When
any is given, it is implicitly sent (with all modified objects) via
the tell mechanism to all family
members. If exe1 or exe2 are given, they are executed
as pre- or post-expressions while the database is locked and protected. See also rollback.
: (pool "db")
-> T
: (put '{1} 'str "Hello")
-> "Hello"
: (commit)
-> T
(con 'lst 'any) -> any
- Connects
any to the first cell of lst, by
(destructively) storing any in the CDR of lst. See
also set and conc.
: (setq C (1 . a))
-> (1 . a)
: (con C '(b c d))
-> (b c d)
: C
-> (1 b c d)
(conc 'lst ..) -> lst
- Concatenates all argument lists (destructively). See also
append and con.
: (setq A (1 2 3) B '(a b c))
-> (a b c)
: (conc A B) # Concatenate lists in 'A' and 'B'
-> (1 2 3 a b c)
: A
-> (1 2 3 a b c) # Side effect: List in 'A' is modified!
(cond ('any1 . prg1) ('any2 . prg2) ..) -> any
- Multi-way conditional: If any of the
anyN conditions evaluates
to non-NIL, prgN is executed and the result returned.
Otherwise (all conditions evaluate to NIL), NIL is
returned. See also nond, if, and,
if2 and when.
: (cond
((= 3 4) (println 1))
((= 3 3) (println 2))
(T (println 3)) )
2
-> 2
(connect 'any1 'any2) -> cnt | NIL
- Tries to establish a TCP/IP connection to a server listening at host
any1, port any2. any1 may be either a
hostname or a standard internet address in numbers-and-dots/colons notation
(IPv4/IPv6). any2 may be either a port number or a service name.
Returns a socket descriptor cnt, or NIL if the
connection cannot be established. See also listen and udp.
: (connect "localhost" 4444)
-> 3
: (connect "some.host.org" "http")
-> 4
(cons 'any ['any ..]) -> lst
- Constructs a new list cell with the first argument in the CAR and the second
argument in the CDR. If more than two arguments are given, a corresponding chain
of cells is built.
(cons 'a 'b 'c 'd) is equivalent to (cons
'a (cons 'b (cons 'c 'd))). See also list.
: (cons 1 2)
-> (1 . 2)
: (cons 'a '(b c d))
-> (a b c d)
: (cons '(a b) '(c d))
-> ((a b) c d)
: (cons 'a 'b 'c 'd)
-> (a b c . d)
(copy 'any) -> any
- Copies the argument
any. For lists, the top level cells are
copied, while atoms are returned unchanged.
: (=T (copy T)) # Atoms are not copied
-> T
: (setq L (1 2 3))
-> (1 2 3)
: (== L L)
-> T
: (== L (copy L)) # The copy is not identical to the original
-> NIL
: (= L (copy L)) # But the copy is equal to the original
-> T
(co ['any [. prg]]) -> any
- Starts, resumes or stops a coroutine with
the tag given by
any. If called without arguments, the tag of the
currently running coroutine is returned. If prg is not given, a
coroutine with that tag will be stopped. Otherwise, if a coroutine running with
that tag is found (pointer equality is used for comparison), its execution is
resumed. Else a new coroutine with that tag is initialized and started.
prg will be executed until it either terminates normally, or until
yield is called. In the latter case
co returns, or transfers control to some other, already running,
coroutine. A coroutine cannot resume itself directly or indirectly. See also
stack, catch and throw.
: (de pythag (N) # A generator function
(if (=T N)
(co 'rt) # Stop
(co 'rt
(for X N
(for Y (range X N)
(for Z (range Y N)
(when (= (+ (* X X) (* Y Y)) (* Z Z))
(yield (list X Y Z)) ) ) ) ) ) ) )
: (pythag 20)
-> (3 4 5)
: (pythag 20)
-> (5 12 13)
: (pythag 20)
-> (6 8 10)
(count 'tree) -> num
- Returns the number of nodes in a database tree. See also
tree and root.
: (count (tree 'nr '+Item))
-> 7
(create 'typ 'sym 'lst . prg)
- Creates or updates database objects of the type
typ with the properties in sym and lst.
It handles large amounts of data, by sorting and traversing each database index
separately. prg is executed repeatedly - and should return a list
of values for the properties in sym and lst - until it
returns NIL. If the fin of
the list is NIL, a new object of type typ is created,
otherwise it should be an existing object to be updated. If sym is
non-NIL, the first column of the input data is assigned to the
sym property and should already be sorted. The rest of the input
data is assigned to the properties in lst. create
allocates heap memory, and builds temporary files which increase disk
requirements while it runs. No explicit lock should be established on the database, and
no other processes should operate on this database while it runs. When creating
more than a few hundred million index entries per file, it might be necessary to
increase the number of open files with e.g. ulimit -n 10000. See
also dbs, new, commit and prune.
# Minimal E/R model
(class +Cls +Entity) # Class
(rel key (+Key +Number)) # with a unique numeric key,
(rel num (+Ref +Number)) # an indexed number,
(rel str (+Ref +String)) # and an indexed string
(dbs
(0 +Cls)
(4 (+Cls key)) # Each index in a different file
(4 (+Cls num))
(4 (+Cls str)) )
# Generating random data
(create '(+Cls) 'key '(num str)
(co 'go # Use a coroutine as generator
(for Key 100000000 # Key is sorted in input
(yield # Return keys, numbers and single-char strings
(list Key (rand) (char (rand 97 122))) ) ) ) )
# Reading from a file in PLIO format
(create '(+Cls) 'key '(num str)
(rd) )
# Reading from a TAB-separated CSV file
(create '(+Cls) 'key '(num str)
(when (split (line) "\t")
(list
(format (car @))
(format (cadr @))
(pack (caddr @)) ) ) )
# Direct, naive approach (without using 'create')
# Don't try this at home! Takes forever due to disk trashing
(prune 0)
(gc 400 200)
(for Key 100000000
(new `(db: +Cls) '(+Cls)
'key Key
'num (rand)
'str (char (rand 97 122)) )
(at (0 . 10000) (commit) (prune 7)) )
(commit)
(prune)
(gc 0)
(ctl 'sym . prg) -> any
- Waits until a write (exclusive) lock (or a read (shared) lock if the first
character of
sym is "+") can be set on the file
sym, then executes prg and releases the lock. If the
file does not exist, it will be created. When sym is
NIL, a shared lock is tried on the current innermost I/O channel,
and when it is T, an exclusive lock is tried instead. See also
in, out, err and pipe.
$ echo 9 >count # Write '9' to file "count"
$ pil +
: (ctl ".ctl" # Exclusive control, using ".ctl"
(in "count"
(let Cnt (read) # Read '9'
(out "count"
(println (dec Cnt)) ) ) ) ) # Write '8'
-> 8
:
$ cat count # Check "count"
8
(ctty 'pid) -> pid
(ctty 'any) -> any | NIL
- Unless called with a short number,
ctty changes the current TTY
device to any (or just sets standard I/O to a PTY if
any is NIL). Otherwise, the local console is prepared
for serving the PicoLisp process with the process ID pid. See also
raw.
: (ctty "/dev/tty")
-> "/dev/tty"
(curry lst . fun) -> fun
- Builds a new function from the list of symbols or symbol-value pairs
lst and the functional expression fun. Each member in
lst that is a pat? symbol
is substituted inside fun by its value. All other symbols in
lst are collected into a job environment. curry is a general
higher-order function, not limited to strict currying (which generates only
single-argument functions).
: (de multiplier (@X)
(curry (@X) (N) (* @X N)) )
-> multiplier
: (multiplier 7)
-> ((N) (* 7 N))
: ((multiplier 7) 3)
-> 21
: (def 'fiboCounter
(curry ((N1 . 0) (N2 . 1)) (Cnt)
(do Cnt
(println
(prog1
(+ N1 N2)
(setq N1 N2 N2 @) ) ) ) ) )
-> fiboCounter
: (pp 'fiboCounter)
(de fiboCounter (Cnt)
(job '((N2 . 1) (N1 . 0))
(do Cnt
(println
(prog1 (+ N1 N2) (setq N1 N2 N2 @)) ) ) ) )
-> fiboCounter
: (fiboCounter 5)
1
2
3
5
8
-> 8
: (fiboCounter 5)
13
21
34
55
89
-> 89
(cut 'cnt 'var) -> lst
- Pops the first
cnt elements (CAR) from the stack in
var. See also pop,
rid and del.
: (setq S '(1 2 3 4 5 6 7 8))
-> (1 2 3 4 5 6 7 8)
: (cut 3 'S)
-> (1 2 3)
: S
-> (4 5 6 7 8)