UNIX — универсальная среда программирования

  d1.sym->type = VAR;
  push(d2);
 }

 print /* pop top value from stack, print it */
 {
  Datum d;

  d = pop;
  printf("\t%.8g\n", d.val);
 }

 prexpr /* print numeric value */
 {
  Datum d;

  d = pop;
  printf("%.8g ", d.val);
 }

 prstr /* print string value */
 {
  printf(%s", (char*)*pc++);
 }

 varread /* read into variable */
 {
  Datum d;
  extern FILE *fin;
  Symbol *var = (Symbol*)*pc++;

 Again:
  switch (fscanf(fin, "%lf", &var->u.val)) {
  case EOF:
  if (moreinput)
  goto Again;
  d.val = var->u.val = 0.0;
  break;
  case 0:
  execerror("non-number read into", var->name);
  break;
  default:
  d.val = 1.0;
  break;
  }
  var->type = VAR;
  push(d);
 }

 Inst *code(f) /* install one instruction or operand */
  Inst f;
 {
  Inst *oprogp = progp;

  if (progp >= &prog[NPROG])
  execerror("program too big", (char*)0);
  *progp++ = f;
  return oprogp;
 }

 execute(p)
  Inst *p;
 {
  for (pc = p; *pc != STOP && !returning; )
  (*((++pc)[-1]));
 }

3.7.4 double

 proc double {
  if ($1 > 1) {
  double($1/2)
  }
  print($1)
 }
 double(1024)

3.7.5 fac

 func fac {
  if ($1 <= 0) return 1 else return $1 * fac($1-1)
 }

3.7.6 fac1

 func fac if ($1 <= 0) return 1 else return $1 * fac($1-1)
 fac(0)
 fac(7)
 fac(10)

3.7.7 fac2

 func fac {
  if ($1 <= 0) {
  return 1
  }
  return $1 * fac($1-1)
 }
 i=0
 while(i<=20){
  print "factorial of ", i, "is ", fac(i), "\n"
  i=i+1
 }

3.7.8 fib

 proc fib {
  a = 0
  b = 1
  while (b < $1) {
  print b
  c = b
  b = a+b
  a = c
  }
  print "\n"
 }

3.7.9 fib2

 {
  n=0
  a=0
  b=1
  while(b<10000000){
  n=n+1
  c=b
  b=a+b
  a=c
  print(b)
  }
  print(n)
 }

3.7.10 fibsum

 proc fib{
  a=1
  b=1
  c=2
  d=3
  sum = a+b+c+d
  while(d<$1){
  e=d+c
  print(e)
  a=b
  b=c
  c=d
  d=e
  sum=sum+e
  }
  print(sum)
 }
 fib(1000)

3.7.11 fibtest

 proc fib {
  a = 0
  b = 1
  while (b < $1) {
  c = b
  b = a+b
  a = c
  }
 }
 i = 1
 while (i < 1000) {
  fib(1000)
  i = i + 1
 }

3.7.12 hoc.h

 typedef struct Symbol { /* symbol table entry */
  char *name;
  short type;
  union {
  double val; /* VAR */
  double (*ptr); /* BLTIN */
  int (*defn); /* FUNCTION, PROCEDURE */
  char *str; /* STRING */
  } u;
  struct Symbol *next; /* to link to another */
 } Symbol;
 Symbol *install, *lookup;

 typedef union Datum { /* interpreter stack type */
  double val;
  Symbol *sym;
 } Datum;
 extern Datum pop;
 extern eval, add, sub, mul, div, negate, power;

 typedef int (*Inst);
 #define STOP (Inst)0

 extern Inst *progp, *progbase, prog[], *code;