ALGOL 68/prelude

The following summarises the useful and various ALGOL 68 prelude templates. These are used in several ALGOL 68 code samples.

Note: These are not part of the classic UNESCO IFIP Working Group 2.1's standard prelude, rather they were specifically created for Rosetta Code's ALGOL 68 code examples.

pow_mod.a68

Used in: Miller-Rabin test, Multiplicative order and Trial factoring of a Mersenne number.

COMMENT
  This routine is used in more than one place, and is essentially a
  template that can by used for many different types, eg INT, LONG INT...
USAGE
  MODE POWMODSTRUCT = INT, LONG INT, COMPL, FRAC, MODULAS, MATRIX etc
  PR READ "prelude/pow_mod.a68" PR
END COMMENT

PROC pow mod = (POWMODSTRUCT b,in e, mod)POWMODSTRUCT: (
  POWMODSTRUCT sq := b, e := in e;
  POWMODSTRUCT out:= IF ODD e THEN b ELSE 1 FI;
  e:=e OVER 2;
  WHILE e /= 0 DO
    sq := sq * sq %* mod;
    IF ODD e THEN out := out * sq %* mod FI ;
    e:=e OVER 2
  OD;
  out
)

sort.a68

Used in: Multiplicative order and Sort most popular programming languages.

COMMENT
  This routine is used in more then one place, and is essentially a
  template that can by used for many different types, eg INT, LONG INT...
USAGE
  MODE SORTSTRUCT = INT, LONG INT, STRUCT(STRING name, addr) etc
  OP < = (SORTSTRUCT a,b)BOOL: ~;

  PR READ "prelude/sort.a68" PR;
  [3]SORTSTRUCT list := (a,b,c);
  print((in place shell sort(list), new line))
END COMMENT

 PROC in place shell sort = (REF FLEX []SORTSTRUCT seq)REF[]SORTSTRUCT:(
     INT inc := ( UPB seq + LWB seq + 1 ) OVER 2;
     WHILE inc NE 0 DO
         FOR index FROM LWB seq TO UPB seq DO
             INT i := index;
             SORTSTRUCT el = seq[i];
             WHILE ( i  - LWB seq >= inc | NOT(seq[i - inc] < el) | FALSE ) DO
                 seq[i] := seq[i - inc];
                 i -:= inc
             OD;
             seq[i] := el
         OD;
         inc := IF inc = 2 THEN 1 ELSE ENTIER(inc * 5 / 11) FI
     OD;
     seq
 );

 PROC in place shell sort reverse = (REF FLEX []SORTSTRUCT seq)REF[]SORTSTRUCT:(
     INT inc := ( UPB seq + LWB seq + 1 ) OVER 2;
     WHILE inc NE 0 DO
         FOR index FROM LWB seq TO UPB seq DO
             INT i := index;
             SORTSTRUCT el = seq[i];
             WHILE ( i  - LWB seq >= inc | seq[i - inc] < el | FALSE ) DO
                 seq[i] := seq[i - inc];
                 i -:= inc
             OD;
             seq[i] := el
         OD;
         inc := IF inc = 2 THEN 1 ELSE ENTIER(inc * 5 / 11) FI
     OD;
     seq
 );
 SKIP

The classic UNESCO IFIP Working Group 2.1's standard prelude contents

Names from the "official" standard prelude: <, <=, +, +:=, +=:, +*, &, ∧, ⌈, ↓, ⌋, ≥, ≤, =, ∨, ⊥, ÷, ÷×, ÷×:=, ÷*, ÷*:=, ÷:=, ×, ×:=, ~, ↑, *, **, *:=, ¬, -, -:=, /, /:=, /=, %, %×, %×:=, %*, %*:=, %:=, >, >=, =, ABS, AND, ARG, BIN, BITS, BOOL, BYTES, CHANNEL, CHAR, COMPL, CONJ, DIVAB, DOWN, ELEM, ENTIER, EQ, FILE, FORMAT, GE, GT, I, IM, INT, LE, LENG, LEVEL, LT, LWB, MINUSAB, MOD, MODAB, NE, NOT, ODD, OR, OVER, OVERAB, PLUSAB, PLUSTO, RE, REAL, REPR, ROUND, SEMA, SHL, SHORTEN, SHR, SIGN, STRING, TIMESAB, UP, UPB, VOID, arccos, arcsin, arctan, associate, backspace, bin possible, bits lengths, bits pack, bits shorths, bits width, blank, bytes lengths, bytes pack, bytes shorths, bytes width, chan, char in string, char number, close, compressible, cos, create, errorchar, estab possible, establish, exp, exp width, fixed, flip, float, flop, get, get bin, get possible, getf, int shorths, int width, last random, line number, ln, lock, make conv, make term, max abs char, max int, max real, newline, newpage, next random, null character, on char error, on format end, on line end, on logical file end, on page end, on physical file end, on value error, open, page number, pi, print, printf, put, put bin, put possible, putf, random, read, read bin, readf, real lengths, real shorths, real width, reidf, reidf possible, reset, reset possible, scratch, set, set char number, set possible, sin, small real, space, sqrt, stand back, stand back channel, stand in, stand in channel, stand out, stand out channel, standconv, stop, tan, whole, write, write bin, writef, L BITS, L BYTES, L COMPL, L INT, L REAL, L arccos, L arcsin, L arctan, L bits pack, L bits width, L bytes pack, L bytes width, L cos, L exp, L exp width, L int width, L last random, L ln, L max int, L max real, L next random, L pi, L random, L real width, L sin, L small real, L sqrt, L tan.

The L indicates extra precision, eg REAL, or LONG REAL or LONG LONG REAL etc, even SHORT REAL etc

These names next were intended for internal compiler use only: אBEYOND, אBFILE, אBOOK, אCOLLECTION, אCOLLITEM, אCONV, אCPATTERN, אFLEXTEXT, אFPATTERN, אFRAME, אGPATTERN, אINSERTION, אINTYPE, אNUMBER, אOUTTYPE, אPATTERN, אPICTURE, אPIECE, אPOS, אROWS, אSFRAME, אSIMPLIN, אSIMPLOUT, אSINSERT, אSTRAIGHTIN, אSTRAIGHTOUT, אTEXT, אalignment, אassociate format, אbfileprotect, אbook bounds, אchainbfile, אchar dig, אcheck pos, אcurrent pos, אdig char, אdo fpattern, אedit string, אfalse, אfile available, אfrom bin, אget char, אget good file, אget good line, אget good page, אget insertion, אget next picture, אgremlins, אidf ok, אindit string, אline ended, אlockedbfile, אlogical file ended, אmatch, אnext pos, אpage ended, אphysical file ended, אput char, אput insertion, אset bin mood, אset char mood, אset mood, אset read mood, אset write mood, אstandardize, אstaticize frames, אstaticize insertion, אstring to L int, אstring to L real, אsubfixed, אsubwhole, אto bin, אundefined, אL standardize