C/C++ Users Group Library 1996 July/C-C++ Users Group Library July 1996.iso/vol_200/231_01/lexcmd.c

C/C++ Source or Header | 1987-06-15 | 5.1 KB | 222 lines

/*
    Little Smalltalk
        misc lexer related routines
        timothy a. budd 12/84
*/
/*
    The source code for the Little Smalltalk System may be freely
    copied provided that the source of all files is acknowledged
    and that this condition is copied with each file.

    The Little Smalltalk System is distributed without responsibility
    for the performance of the program and without any guarantee of
    maintenance.

    All questions concerning Little Smalltalk should be addressed to:

        Professor Tim Budd
        Department of Computer Science
        Oregon State University
        Corvallis, Oregon
        97331
        USA
*/
# include <stdio.h>
# include "env.h"
# include <ctype.h>

extern char toktext[];

/* dolexcommand - read a ) type directive, and process it */
dolexcommand(p)
char *p;
{       char *q, buffer[100];

    /* replace trailing newline with end of string */
    for (q = p; *q && *q != '\n'; q++);
    if (*q == '\n') *q = '\0';

        switch( *++p) {
           case '!':
# ifndef NOSYSTEM
        system(++p);
# endif
        break;

           case 'e': for (++p; isspace(*p); p++);
             if (! lexedit(p)) lexinclude(p);
                     break;

       case 'g': for (++p; isspace(*p); p++);
             sprintf(buffer,"%s/%s", LIBLOC, p);
             lexread(buffer);
             break;

           case 'i': for (++p; isspace(*p); p++);
                     lexinclude(p);
                     break;

           case 'r': for (++p; isspace(*p); p++);
                     lexread(p);
                     break;

       case 's': for(++p; isspace(*p); p++);
             dosave(p);
             break;

       case 'l': for(++p; isspace(*p); p++);
             doload(p);
             break;

           default:  lexerr("unknown command %s", toktext);
           }
}

/* doload/dosave routines written by nick buchholz */
/*
    doload and dosave routines make the following assumptions
    1. version is the first global variable declared in main.
    2. main is the first procedure seen by the loader
    3. the loader allocates memory in the order it sees the procedures
    4. memory is laid out as on the vax 780 under 4.2

    on other machines any or all of these might be false and the
    doload/dosave routines will not work
*/
extern int version;

dosave(p) char *p;{
    int fd;
    char *start, *end, *sbrk();
    unsigned int length, len;
    int dlen;

# ifdef OPEN3ARG
    if ((fd = open(p, O_WRONLY|O_CREAT|O_TRUNC, 0666)) == -1)
# endif
# ifndef OPEN3ARG
    if ((fd = creat(p, 0666)) == -1)
# endif
       fprintf(stderr,"can't open: %s\n",p);

    start = (char *) &version;
    end = sbrk(0);
    length = end - start;

    write(fd, &version, sizeof(int));
    write(fd, &start, sizeof(char *));
    write(fd, &length, sizeof(unsigned int));

    for (len = 0; len < length; len += dlen) {
    dlen = ((length - len) > 512) ? 512 : (length - len);
    if (dlen != write(fd, start + len, dlen)) {
        cant_happen(23);
        }
    }

    fprintf(stderr,"%u bytes written\n",len);

    close(fd);
}

# ifdef ENVSAVE
extern char **environ;
# endif

doload(p) char *p;{
    int fd;
    char *start, *end, *brk();
    unsigned int length, len;
    int dlen;
    int test;
# ifdef ENVSAVE
    char **evsave;
# endif

# ifdef OPEN3ARG
    if ((fd = open(p, O_RDONLY, 0)) == -1)
# endif
# ifndef OPEN3ARG
    if ((fd = open(p, 0 )) == -1)
# endif
    fprintf(stderr,"no such context as: %s\n", p);

    else {
    read(fd, &test, sizeof(int));
    read(fd, &start, sizeof(char *));
    read(fd, &length, sizeof(unsigned int));

    if ((test != version) || (start != (char *) &version))
        fprintf(stderr,"%s: not a valid context file for version %d\n",
                p, version);
    else {
        start = (char *) &version;
        end = brk(start + length + 1);
# ifdef ENVSAVE
        evsave = environ;
# endif

            for (len = 0; len < length; len += dlen) {
        dlen = ((length - len) > 512) ? 512 : (length - len);
        if (dlen != read(fd, start + len, dlen)) {
            cant_happen(23);
            }
        }
# ifdef ENVSAVE
       environ = evsave;
# endif
        fprintf(stderr,"%u bytes read\n",len);
    }
    close(fd);
    }
}

/* lexread - read commands from a file */
lexread(name)
char *name;
{    FILE *fd;

    fd = fopen(name, "r");
    if (fd == NULL) {
        fprintf(stderr,"can't open %s\n", name);
        }
    else {
        set_file(fd);
        }
}

/* lexinclude - parse a class and include the class description */
lexinclude(name)
char *name;
{  char template[60], cmdbuf[120];
   int  i;

# ifndef NOSYSTEM
   gettemp(template);
   sprintf(cmdbuf,"%s %s >%s", PARSER, name, template);
   i = system(cmdbuf);
   if (i == 0)
       lexread(template);
# endif
# ifdef NOSYSTEM
   fprintf(stderr,")i does not work on this system\n");
# endif
}

/* lexedit - edit a class description */
int lexedit(name)
char *name;
{    char *e, buffer[100], *getenv();

# ifndef NOSYSTEM
    e = getenv("EDITOR");
    if (!e) e = "ed";
    sprintf(buffer,"%s %s", e, name);
    return(system(buffer));
# endif
# ifdef NOSYSTEM
    fprintf(stderr,")e does not work on this system\n");
    return(1);
# endif
}