Брайан Керниган - UNIX — универсальная среда программирования Страница 97

  return STRING;

 }

 switch (c) {

 case '>': return follow('=', GE, GT);

 case '<': return follow('=', LE, LT);

 case '=': return follow('=', EQ, '=');

 case '!': return follow('=', NE, NOT);

 case '|': return follow(' |', OR, '|');

 case '&': return follow('&', AND, '&');

 case '\n': lineno++; return '\n';

 default: return c;

 }

}

backslash(c) /* get next char with \'s interpreted */

 int c;

{

 char *index(); /* 'strchr()' in some systems */

 static char transtab[] = "b\bf\fn\nr\rt\t";

 if (c != '\\')

  return c;

 с = getc(fin);

 if (islower(c) && index(transtab, c))

  return index(transtab, с)[1];

 return c;

}

follow(expect, ifyes, ifno) /* look ahead for >=, etc. */

{

 int с = getc(fin);

 if (c == expect)

  return ifyes;

 ungetc(c, fin);

 return ifno;

}

defnonly(s) /* warn if illegal definition */

 char *s;

{

 if (!indef)

  execerror(s, "used outside definition");

}

yyerror(s) /* report compile-time error */

 char *s;

{

 warning(s, (char *)0);

}

execerror(s, t) /* recover from run-time error */

 char *s, *t;

{

 warning(s, t);

 fseek(fin, 0L, 2); /* flush rest of file */

 longjmp(begin, 0);

}

fpecatch() /* catch floating point exceptions */

{

 execerror("floating point exception", (char*)0);

}

main(argc, argv) /* hoc6 */

 char *argv[];

{

 int i, fpecatch();

 progname = argv[0];

 if (argc == 1) { /* fake an argument list */

  static char *stdinonly[] = { "-" };

  gargv = stdinonly;

  gargc = 1;

 } else {

  gargv = argv+1;

  gargc = argc-1;

 }

 init();

 while (moreinput())

  run();

 return 0;

}

moreinput() {

 if (gargc-- <= 0)

  return 0;

 if (fin && fin != stdin)

  fclose(fin);

 infile = *gargv++;

 lineno = 1;

 if (strcmp(infile, "-") == 0) {

  fin = stdin;

  infile = 0;

 } else if ((fin=fopen(infile, "r")) == NULL) {

  fprintf (stderr, "%s: can't open %s\n", progname, infile);

  return moreinput();

 }

 return 1;

}

run() /* execute until EOF */

{

 setjmp(begin);

 signal(SIGFPE, fpecatch);

 for (initcode(); yyparse(); initcode())

  execute(progbase);

}

warning(s, t) /* print warning message */

 char *s, *t;

{

 fprintf(stderr, "%s: %s", progname, s);

 if (t)

  fprintf(stderr, " %s", t);

 if (infile)

  fprintf(stderr, " in %s", infile);

 fprintf(stderr, " near line %d\n", lineno);

 while (c != '\n' && c != EOF)

  с = getc(fin); /* flush rest of input line */

 if (c == '\n')

  lineno++;

}

3.7.15 init.c

#include "hoc.h"

#include "y.tab.h"

#include <math.h>

extern double Log(), Log10(), Sqrt(), Exp(), integer();

static struct { /* Keywords */

 char *name;

 int kval;

} keywords[] = {

 "proc",   PROC,

 "func",   FUNC,

 "return", RETURN,

 "if",     IF,

 "else",   ELSE,

 "while",  WHILE,

 "print",  PRINT,

 "read",   READ,

 0,        0,

};

static struct { /* Constants */

 char *name;

 double eval;

} consts[] = {

 "PI",    3.14159265358979323846,

 "E",     2.71828182845904523536,

 "GAMMA", 0.57721566490153286060, /* Euler */

 "DEG",  57.29577951308232087680, /* deg/radian */

 "PHI",   1.61803398874989484820, /* golden ratio */

 0,       0

};

static struct { /* Built-ins */

 char *name;

 double (*func)();

} builtins[] = {

 "sin",   sin,

 "cos",   cos,

 "atan",  atan,

 "log",   Log, /* checks range */

 "log10", Log10, /* checks range */

 "exp",   Exp, /* checks range */

 "sqrt",  Sqrt, /* checks range */

 "int",   integer,

 "abs",   fabs,

 0, 0

};

init() /* install constants and built-ins in table */

{

 int i;

 Symbol *s;

 for (i = 0; keywords[i].name; i++)

  install(keywords[i].name, keywords[i].kval, 0.0);

 for (i = 0; consts[i].name; i++)

  install(consts[i].name, VAR, consts[i].eval);

 for (i = 0; builtins[i].name; i++) {

  s = install(builtins[i].name, BLTIN, 0.0);

  s->u.ptr = builtins[i].func;

 }

}

3.7.16 makeapp

#!/bin/sh

cd hoc6

for i in hoc.y hoc.h symbol.c code.c init.c math.c makefile

do

 echo "

**** $i ***************************************

"

 sed 's/\\/\\e/g

 s/^$/.sp .5/' $i |

 awk '

                      { print }

  /(^ ;$)|(^})|(^%%)/ { print ".P3" }

 '

done

3.7.17 makefile

CC = lcc

YFLAGS = -d

OBJS = hoc.o code.o init.o math.o symbol.o

hoc6: $(OBJS)

      $(CC) $(CFLAGS) $(OBJS) -lm -o hoc6

hoc.o code.o init.o symbol.o: hoc.h

code.o init.o symbol.o: x.tab.h

x.tab.h: y.tab.h

      -cmp -s x.tab.h y.tab.h || cp y.tab.h x.tab.h

pr: hoc.y hoc.h code.c init.c math.c symbol.c

      @pr $?

      @touch pr

clean:

      rm -f $(OBJS) [xy].tab.[ch]

3.7.18 math.c

#include <math.h>

#include <errno.h>

extern int errno;

double errcheck();

double Log(x)

 double x;

{

 return errcheck(log(x), "log");

}

double Log10(x)

 double x;

{

 return errcheck(log10(x), "log10");

}

double Sqrt(x)

 double x;

{

 return errcheck(sqrt(x), "sqrt");

}

double Exp(x)

 double x;

{

 return errcheck(exp(x), "exp");

}

double Pow(x, y)

 double x, y;

{

 return errcheck(pow(x,y), "exponentiation");

}

double integer(x)

 double x;

{

 return (double)(long)x;

}

double errcheck(d, s) /* check result of library call */

 double d;

 char *s;

{

 if (errno == EDOM) {

  errno = 0;

  execerror(s, "argument out of domain");

 } else if (errno == ERANGE) {

  errno = 0;

  execerror(s, "result out of range");

 }

 return d;

}

3.7.19 mbox

From: Polyhedron Software Ltd <[email protected]>

To: ">INTERNET:[email protected]" <[email protected] >

Subject: Message from Internet

Date: 10 May 91 04:07:07 EDT

Message-Id: <"910510080707 100013.461 CHE27-1"@CompuServe.COM>

Got your message. I'll pass it on to Tony. We haven't noticed any

errors at all in CompuServe mail, so far.

Regards

Graham Wood

From kam Thu May 9 10:58:06 EDT 1991

tony fritzpatrick called from england. he had spoken to you

last week about compuserve.

the number is:

100013,461

this is regarding the HOC6 listing.

he will call you back tomorrow

From pipe!subll276 Fri May 3 10:38:29 EDT 1991

Message to: BK

From: Tony Fitzpatrick

ECL

Highlands Farm

Greys Road

Henley OXON, RG 94 PS

ENGLAND

Telephone: 0491 - 575-989 (country code 45)

FAX: 0491 576 557

1. H would like permission

   (which has already been granted by publisher) to

   use HUC 6 program — commercial software.

2. Is the listing available on floppy disk?

3. Thank you for a very interesting and useful book.

4. He left his fax # and telephone #. He wasn't sure of the country code.

   He would appreciate hearing from you via fax.

sub 11276

3.7.20 symbol.c

#include "hoc.h"

#include "y.tab.h"

static Symbol *symlist =0; /* symbol table: linked list */

Symbol *lookup(s) /* find s in symbol table */

 char *s;

{

 Symbol *sp;

 for (sp = symlist; sp != (Symbol*)0; sp = sp->next)

  if (strcmp(sp->name, s) == 0)

   return sp;

 return 0; /* 0 ==> not found */

}

Symbol *install(s, t, d) /* install s in symbol table */

 char *s;

 int t;

 double d;