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HOW TO RETURN index doc: PUT {} IN where FOR line.no IN keys doc: TREAT LINE RETURN where TREAT LINE: FOR word IN split doc[line.no]: IF word not.in keys where: PUT {} IN where[word] INSERT line.no IN where[word]
PROGRAM ONE WHEEL " Simple model of a dynamical system " written in ACSL 1, circa 1982. INITIAL CINTERVAL CINT = 0.05 ALGORITHM IALG = 4 $ "RK3" CONSTANT X1IO = 0.0, X2IO=0.0, X1DIC=0.0, X2DIC = 0.0 CONSTANT M1 = 25.0, M2=2.0, DF=100.0, K2=5000 CONSTANT TDONE = 15.0 K1 = 1000.0 END $ "OF INITIALIZATION" DYNAMIC DERIVATIVE X3= STEP(0.0) X1D = INTEG((-DF/M1)*(X1D-X2D) - (K1/M1)*(X1-X2), X1DIC) X2D = INTEG((-DF/M1)*(X1D-X2D) - (K1/M1)*(X1-X2), ... (K2/M2)*(X2-X3*5.0), X2DIC) X1 = INTEG(X1D,X1IO) X2 = INTEG(X2D,X2IO) END "OF DERIVATIVE SECTION" TERMT(T .GE. TDONE) END "OF DYNAMIC SECTION" END "OF PROGRAM"
-- simple programming with floating-point #s with Ada.Float_Text_IO; use Ada.Float_Text_IO; procedure Think is A, B : Float := 0.0; -- A and B initially zero; note the period. I, J : Integer := 1; begin A := B * 7.0; I := J * 3; B := Float(I) / A; Put(B); end Think;
/* An Alef program to parse numbers out of * the string returned from /dev/time, and * print them from a separate proc. This is * a rather lame conglomeration of several * examples from Bob Flandrea's Alef * User's Guide */ tuple(int, uint, byte*) strtoui(byte* str, int base) { int val; while(*str != 0 && whitespace(*str)) str ; if(str == nil || *str == 0) return(0, 0, str); while(*str && !whitespace(*str)) { if(!validdigit(*str, base)) return (-1, val, str 1); /* extract digit into val */ str ; } return(1, val, str); } void receive(chan(uint) c) { int s; s = <-c; print("%d\n", s); if (s == 0) terminate(nil); } void main(void) { chan(uint) c; alloc c; proc receive(c); int ret; uint val; int fd; byte *p, buf[128], *newp; fd = open("/dev/time", OREAD|OCEXEC); if (fd >= 0) { read(fd, buf, sizeof(buf)); for(p = buf; *p; p = newp) { (ret, val, newp) = strtoui(p, 10); if(ret >= 0) c <-= val; if(ret == 0) break; } } }
// the main program, calculate the mean of // some numbers begin integer N; Read Int(N); begin real array Data[1:N]; real sum, avg; integer i; sum:=0; for i:=1 step 1 until N do begin real val; Read Real(val); Data[i]:=if val<0 then -val else val end; for i:=1 step 1 until N do sum:=sum Data[i]; avg:=sum/N; Print Real(avg) end end
Here is a better example, written in the
Algol60 publication language, from
Jean Sammet courtesy of
Glyn Webster.
procedure problem (a, b); value a, b; integer a, b; begin integer k; real e; for k := 2 × (a ÷ 2) 1 step 2 until b do begin e := if prime(k) then sqrt(3 × k sin(k)) else sqrt(4 × k cos(k)); if prime(k) then putlist(k, e, 'prime') else putlist(k, e, 'nonprime') end end problem;
-- Use the Finder to close all applications -- (by Joshua D. Baer) property specialApps : {"Finder"} tell application "Finder" set allApps to name of processes end tell repeat with someParticularApp in allApps if specialApps does not contain someParticularApp then tell application someParticularApp activate quit end tell end if end repeat
;; Very simple example of interactive extension ;; for AutoCAD (Defun c:SF2ACRE () (setq SF (getreal "Enter area in square feet: ")) (setq AGREAGE (/ SF 43560.0)) (alert (strcat "\nThe area in acres is " (rtos ARGEAGE 2 2))) )
BEGIN { if ("'$#argv'"==1) Col="'$1'"; else Col=1 } {Total = $Col; }; END { printf "Total for column %d with %d items: %d\n", Col,NR,Total }
class ACCOUNT feature balance: INTEGER; owner: PERSON; minimum_balance: INTEGER is 1000 open (who: PERSON) is -- Assign the account to owner who. do owner := who end deposit (sum: INTEGER) is -- Deposit sum into the account. do add (sum) end withdraw (sum: INTEGER) is -- Withdraw sum from the account. do add (-sum) end may_withdraw (sum: INTEGER): BOOLEAN is -- Is there enough money to withdraw sum? do Result := (balance >= sum + minimum_balance) end feature {NONE} add (sum: INTEGER) is -- Add sum to the balance. do balance := balance + sum end end -- class ACCOUNT
;; Simple Elisp example (defconst date-pattern-1 "\\(1?[0-9]\\)/\\([123]?[0-9]\\)/\\([0-9][0-9]\\)" "Regexp for one style of data string") (defun replace-all-dates () "Replace 1/27/93 dates with 27-1-93 dates" (interactive) (let ((mcount 0)) (while (re-search-forward date-pattern-1 nil t) (replace-match "\\2-\\1-\\3" nil nil) (setq mcount (+ 1 mcount))) (message (format "Replaced %d dates" mcount))) )
-module(sort). -export([sort/1]). sort([]) -> []; sort([Pivot|Rest]) -> {Smaller, Bigger} = split(Pivot, Rest), lists:append(sort(Smaller), [Pivot|sort(Bigger)]). split(Pivot, L) -> split(Pivot, L, [], []). split(Pivot, [], Smaller, Bigger) -> {Smaller, Bigger}; split(Pivot, [Hd|Tl], Smaller, Bigger) when Hd < Pivot -> split(Pivot, Tl, [Hd|Smaller], Bigger); split(Pivot, [Hd|Tl], Smaller, Bigger) when Hd >= Pivot -> split(Pivot, T, Smaller, [Hd|Bigger]).
Alternative version using Erlang 4.4 features:
-module(sort). -export([sort/1]). sort([Pivot|T]) -> sort([ X || X <- T, X < Pivot]) ++ [Pivot] ++ sort([ X || X <- T, X >= Pivot]); sort([]) -> [].
MODULE Lambda. CONSTRUCT Person/0. FUNCTION Jane, Mary, John: One -> Person. FUNCTION Mother : Person * Person -> Boolean. Mother(x,y) => x=Jane & y=Mary. FUNCTION Wife : Person * Person -> Boolean. Wife(x,y) => x=John & y=Jane. FUNCTION PrimitiveRel : (Person * Person -> Boolean) -> Boolean. PrimitiveRel(r) => r=Mother \/ r=Wife. FUNCTION Rel : (Person * Person -> Boolean) -> Boolean. Rel(r) => PrimitiveRel(r) \/ (SOME [r1,r2] (r = LAMBDA [u] (SOME [z] (r1(Fst(u),z) & r2(z,Snd(u)))) & PrimitiveRel(r1) & PrimitiveRel(r2))).
module AVERAGE: input INCREMENT_AVERAGE(integer); output AVERAGE_VALUE(integer); var TOTAL := 0, NUMBER := 0, : integer in every immediate INCREMENT_AVERAGE do TOTAL := TOTAL + ? INCREMENT_AVERAGE; NUMBER := NUMBER + 1; emit AVERAGE_VALUE (TOTAL / NUMBER) end end.
-- Prime sieve benchmark, adapted from Euphoria 2.0beta demos constant ON = 1, OFF = 0, SIZE = 5000, BATCH = 20 function sieve() sequence flags integer prime, start, count, still_prime count = 0 flags = repeat(ON, SIZE) for i = 1 to SIZE do still_prime = flags[i] if still_prime then prime = 2 * i prime = prime + 1 start = prime + i for k = start to SIZE by prime do flags[k] = OFF end for count = count + 1 end if end for return count end function atom t, cycles, p cycles = 0 t = time() while time() < t + 30 do -- test for 30 seconds for iter = 1 to BATCH do p = sieve() end for cycles = cycles + BATCH end while t = time() - t printf(1, "%6.1f sieves per second\n", cycles / t)
func cmplxplot(z, u) /* DOCUMENT cmplxplot, z, u * plots a scalar complex function of a complex variable. */ { resx=100; resy=100; s=[[sqrt(2./3.),0,1/sqrt(3)],[-1/sqrt(2*3.0),1/sqrt(2.),1/sqrt(3)], [-1/sqrt(2*3.0),-1/sqrt(2.),1/sqrt(3)]]; phi=span(-pi,pi,256); vec=array(double,3,256); vec(1,)=cos(phi); vec(2,)=sin(phi); vec(3,)=1/sqrt(2)(-); f=s(+,)*vec(+,); palette,bytscl(f(2,),top=255),bytscl(f(1,),top=255),bytscl(f(3,),top=255); xmin=min(u.re); xmax=max(u.re); ymin=min(u.im); ymax=max(u.im); zi=array(complex,resx,resy); zi.re=interp2(span(ymin,ymax,resy)(-:1:resx,),span(xmin,xmax,resx)(,-:1:resy), z.re,u.im,u.re); zi.im=interp2(span(ymin,ymax,resy)(-:1:resx,),span(xmin,xmax,resx)(,-:1:resy), z.im,u.im,u.re); // Caution: on some platforms atan(0,0) crashes ! arr=bytscl(atan(zi.im,zi.re+1e-200),cmin=-pi,cmax=pi); pli,arr, xmin,ymin,xmax,ymax; plc,abs(z),u.im,u.re,marks=0; }
(* Oberon module to read in numbers *) (* average them. *) MODULE Stats; IMPORT Texts, Oberon; TYPE Stat* = POINTER TO StatRec; StatRec *= RECORD count: LONGINT; total: REAL; END; PROCEDURE (s: Stat) Add* (REAL val); VAR this: Stat; BEGIN this := s; this.total := this.total + val; this.count := this.count + 1; END Add; PROCEDURE (s: Stat) Reset*; VAR this: Stat; BEGIN this := s; this.total := 0.0; this.count := 0; END Reset; PROCEDURE (s: Stat) IsValid*: BOOLEAN; VAR this: Stat; BEGIN this := s; RETURN (this.count > 0); END Reset; PROCEDURE (s: Stat) Average*: REAL; VAR this: Stat; BEGIN this := s; IF this.IsValid^() THEN RETURN 0.0 ELSE RETURN (this.total / this.count) END Average; END Stats;
/* still need an example here */
Server side:
(* A server for computing factorials. *) module FactServer; let fact = net_export("fact","", { m => meth(s,n) if n is 0 then 1 else n * s.m(n-1) end end });
Client side:
module FactClient; let fact = net_import("fact",""); fact.m(13);
-- Pipelined parallel sort in occam --(from Pountain and May, A Tutorial -- Introduction to Occam Programming) VAL numbers IS 100 : [numbers + 1] CHAN OF INT pipe: PAR PAR i = 0 FOR numbers input IS pipe[i] : output IS pipe[i+1] : INT highest : SEQ input ? highest SEQ j = 0 FOR numbers - 1 INT next: SEQ input ? next IF next <= highest output ! highest next > highest SEQ output ! highest highest := next SEQ i = 0 FOR numbers -- get unsorted INT unsortednumber : -- numbers SEQ input ? unsortednumber pipe[0] ! unsortednumber SEQ i = 0 FOR numbers -- dump sorted INT sortednumber : -- numbers SEQ pipe[numbers] ? sortednumber output ! sortednumber
; An OPS5 program that implements a model of ; rock climbers, from exercise solutions of ; "Expert Systems Programming in OPS5" (literalize rock-climber age ; young or old style ; timid or bold ) (p old-not-bold (rock-climber ^age old ^style <> bold) ---> (write (crlf) that is plausible)) (p bold-not-old (rock-climber ^age <> old ^style bold) ---> (write (crlf) that is quite possible)) (p error::old-and-bold (rock-climber ^age old ^style bold) ---> (write (crlf) There are no old, bold rock climbers)) (make rock-climber ^age young ^style bold)
# An example object from the paper # "Experiences with the Orca Programming Language" # by Bal and Wilson OBJECT IMPLEMENTATION buffer; CONST MAXSIZE = 10; # Maximum size of the buffer # Local state of the object: buf:ARRAY[integer 0..MAXSIZE-1] OF integer; # the buffer itself in, out: integer; # index of next element to put/get size: integer; # current size OPERATION put(x: integer); BEGIN GUARD size ! MAXSIZE DO # blocks until there is room buf[in] := x; # store element in := (in + 1) % MAXSIZE; # bump input index size +:= 1; # increment size OD; END; OPERATION get(x: OUT integer); BEGIN GUARD size ? 0 DO # blocks while buffer is empty x := buf[out]; # retrieve element out := (out + 1) % MAXSIZE; # bump output index size -:= 1; # decrement size OD; END; END;
local proc {AndThen BP1 BP2 ?B} case {BP1} then case {BP2} then B = true else B = false end else B = false end end in proc {BinaryTree T ?B} case T of nil then B = true [] tree(K V T1 T2) then {AndThen proc {$ B1}{BinaryTree T1 B1} end proc {$ B2}{BinaryTree T2 B2} end B} else B = false end end end
% This is one of the example programs % included with the V1.4 distribution. MODULE EightQueens. IMPORT Lists. PREDICATE Queen : List(Integer). Queen(x) <- Safe(x) & Permutation([1,2,3,4,5,6,7,8], x). PREDICATE Safe : List(Integer). DELAY Safe(x) UNTIL NONVAR(x). Safe([]). Safe([x|y]) <- NoDiagonal(x,1,y) & Safe(y). PREDICATE NoDiagonal : Integer * Integer * List(Integer). DELAY NoDiagonal(_,_,z) UNTIL NONVAR(z). NoDiagonal(_,_,[]). NoDiagonal(x,y,[z|w]) <- y ~= Abs(z - x) & NoDiagonal(x,y+1,w).
BARBERS STORAGE 20 GENERATE RVEXPO(1,1.5) QUEUE CUSTOMS ENTER BARBERS UNLINK MIN BARBERS,BARBGO,1,(UTIL)PL LINK CUSTOMS CLEAVE AVANCE .5 TERMINATE BARBGEN GENERATE ,,,20,5,1PH,1PL 20 BARBERS ASSIGN IBARB,N(BARBGEN),,PH LINK BARBERS,FIFO BARBGO SEIZE PH(IBARB) ADVANCE RVEXPO(1,30) RELEASE PH(IBARB) LEAVE BARBERS ASSIGN BUSE,FR(PH(IBARB)),,PL UNLINK CUSTOMS,CLEAVE,1 LINK BARBERS,FIFO GENERATE 60*10 TERMINATE 1 START 1
(* Oberon module to read in numbers *) (* average them. *) MODULE Stats; IMPORT Texts, Oberon; TYPE Stat* = POINTER TO StatRec; StatRec *= RECORD count: LONGINT; total: REAL; END; PROCEDURE (s: Stat) Add* (REAL val); VAR this: Stat; BEGIN this := s; this.total := this.total + val; this.count := this.count + 1; END Add; PROCEDURE (s: Stat) Reset*; VAR this: Stat; BEGIN this := s; this.total := 0.0; this.count := 0; END Reset; PROCEDURE (s: Stat) IsValid*: BOOLEAN; VAR this: Stat; BEGIN this := s; RETURN (this.count > 0); END Reset; PROCEDURE (s: Stat) Average*: REAL; VAR this: Stat; BEGIN this := s; IF this.IsValid^() THEN RETURN 0.0 ELSE RETURN (this.total / this.count) END Average; END Stats;
/* still need an example here */
Server side:
(* A server for computing factorials. *) module FactServer; let fact = net_export("fact","", { m => meth(s,n) if n is 0 then 1 else n * s.m(n-1) end end });
Client side:
module FactClient; let fact = net_import("fact",""); fact.m(13);
-- Pipelined parallel sort in occam --(from Pountain and May, A Tutorial -- Introduction to Occam Programming) VAL numbers IS 100 : [numbers + 1] CHAN OF INT pipe: PAR PAR i = 0 FOR numbers input IS pipe[i] : output IS pipe[i+1] : INT highest : SEQ input ? highest SEQ j = 0 FOR numbers - 1 INT next: SEQ input ? next IF next <= highest output ! highest next > highest SEQ output ! highest highest := next SEQ i = 0 FOR numbers -- get unsorted INT unsortednumber : -- numbers SEQ input ? unsortednumber pipe[0] ! unsortednumber SEQ i = 0 FOR numbers -- dump sorted INT sortednumber : -- numbers SEQ pipe[numbers] ? sortednumber output ! sortednumber
; An OPS5 program that implements a model of ; rock climbers, from exercise solutions of ; "Expert Systems Programming in OPS5" (literalize rock-climber age ; young or old style ; timid or bold ) (p old-not-bold (rock-climber ^age old ^style <> bold) ---> (write (crlf) that is plausible)) (p bold-not-old (rock-climber ^age <> old ^style bold) ---> (write (crlf) that is quite possible)) (p error::old-and-bold (rock-climber ^age old ^style bold) ---> (write (crlf) There are no old, bold rock climbers)) (make rock-climber ^age young ^style bold)
# An example object from the paper # "Experiences with the Orca Programming Language" # by Bal and Wilson OBJECT IMPLEMENTATION buffer; CONST MAXSIZE = 10; # Maximum size of the buffer # Local state of the object: buf:ARRAY[integer 0..MAXSIZE-1] OF integer; # the buffer itself in, out: integer; # index of next element to put/get size: integer; # current size OPERATION put(x: integer); BEGIN GUARD size ! MAXSIZE DO # blocks until there is room buf[in] := x; # store element in := (in + 1) % MAXSIZE; # bump input index size +:= 1; # increment size OD; END; OPERATION get(x: OUT integer); BEGIN GUARD size ? 0 DO # blocks while buffer is empty x := buf[out]; # retrieve element out := (out + 1) % MAXSIZE; # bump output index size -:= 1; # decrement size OD; END; END;
local proc {AndThen BP1 BP2 ?B} case {BP1} then case {BP2} then B = true else B = false end else B = false end end in proc {BinaryTree T ?B} case T of nil then B = true [] tree(K V T1 T2) then {AndThen proc {$ B1}{BinaryTree T1 B1} end proc {$ B2}{BinaryTree T2 B2} end B} else B = false end end end
Descriptions in this dictionary are ©1997-99 Neal Ziring. Some examples copyright of their respective authors. Some technologies and languages are trademarked. Permission to copy descriptions is granted as long as authorship credit is preserved.
Comments on this dictionary, corrections and suggestions, are all welcome. Please use email, the address is ziring@home.com
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Dictionary and script maintained by Neal Ziring, last major modifications 3/18/98. Most recent additions to dictionary and master list, 1/00.