front.c

另一款电路设计软件

/**********
Copyright 1990 Regents of the University of California.  All rights reserved.
Author: 1985 Wayne A. Christopher, U. C. Berkeley CAD Group
**********/

/*
 * The front-end command loop.
 */

#include "spice.h"
#include "util.h"
#include "cpdefs.h"
#include "suffix.h"

static char *doblock();
static void docommand();
static void dodump();
static struct control *findlabel();
static wordlist *getcommand();
static void pwlist();

/* Return values from doblock().  I am assuming that nobody will use these
 * characters in a string.
 */

#define NORMAL      '\001'
#define BROKEN      '\002'
#define CONTINUED   '\003'
#define NORMAL_STR  "\001"
#define BROKEN_STR  "\002"
#define CONTINUED_STR   "\003"

/* Are we waiting for a command? This lets (void) signal handling be 
more clever. */

bool cp_cwait = false;      
char *cp_csep = ";";

bool cp_dounixcom = false;


/* Stuff to do control structures. We keep a history (seperate from the
 * cshpar history, for now at least) of commands and their event numbers,
 * with a block considered as a statement. In a goto, the first word in
 * co_text is where to go, likewise for label. For conditional controls,
 * we have to call ft_getpnames and ft_evaluate each time, since the
 * dvec pointers will change... Also we should do variable and backquote
 * substitution each time...
 */

struct control {
    int co_type;            /* One of CO_* ... */
    wordlist *co_cond;      /* if, while, dowhile */
    char *co_foreachvar;        /* foreach */
    int co_numtimes;        /* repeat, break & continue levels */
    wordlist *co_text;      /* Ordinary text and foreach values. */
    struct control *co_parent;  /* If this is inside a block. */
    struct control *co_children;    /* The contents of this block. */
    struct control *co_elseblock;   /* For if-then-else. */
    struct control *co_next;
    struct control *co_prev;
} ;

#define CO_UNFILLED 0
#define CO_STATEMENT    1
#define CO_WHILE    2
#define CO_DOWHILE  3
#define CO_IF       4
#define CO_FOREACH  5
#define CO_BREAK    6
#define CO_CONTINUE 7
#define CO_LABEL    8
#define CO_GOTO     9
#define CO_REPEAT   10

/* We have to keep the control structures in a stack, so that when we do
 * a 'source', we can push a fresh set onto the top...  Actually there have
 * to be two stacks -- one for the pointer to the list of control structs,
 * and one for the 'current command' pointer...
 */

#define CONTROLSTACKSIZE 256    /* Better be enough. */

static struct control *control[CONTROLSTACKSIZE], *cend[CONTROLSTACKSIZE];
static int stackp = 0;

/* If there is an argument, give this to cshpar to use instead of stdin. In
 * a few places, we call cp_evloop again if it returns 1 and exit (or close
 * a file) if it returns 0... Because of the way sources are done, we can't
 * allow the control structures to get blown away every time we return --
 * probably every time we type source at the keyboard and every time a
 * source returns to keyboard input is ok though -- use ft_controlreset.
 */

static char *noredirect[] = { "stop", NULL } ;  /* Only one?? */

int
cp_evloop(string)
    char *string;
{
    wordlist *wlist, *ww;
    struct control *x;
    char *i;
    int nn;

#define newblock    cend[stackp]->co_children = alloc(struct control);      \
	    ZERO(cend[stackp]->co_children,struct control), \
            cend[stackp]->co_children->co_parent = cend[stackp]; \
            cend[stackp] = cend[stackp]->co_children;        \
            cend[stackp]->co_type = CO_UNFILLED;

    for (;;) {
        wlist = getcommand(string);
        if (wlist == NULL) {    /* End of file or end of user input. */
            if (cend[stackp]->co_parent && !string) {
                cp_resetcontrol();
                continue;
            } else
                return (0);
        }
        if ((wlist->wl_word == NULL) || (*wlist->wl_word == '\0')) {
            /* User just typed return. */
            if (string)
                return (1);
            else {
                cp_event--;
                continue;
            }
        }

        /* Just a check... */
        for (ww = wlist; ww; ww = ww->wl_next)
            if (!ww->wl_word) {
                fprintf(cp_err, 
            "cp_evloop: Internal Error: NULL word pointer\n");
                continue;
            }


        /* Add this to the control structure list. If cend->co_type
         * is CO_UNFILLED, the last line was the beginning of a 
         * block, and this is the unfilled first statement.
         */
        if (cend[stackp] && (cend[stackp]->co_type != CO_UNFILLED)) {
            cend[stackp]->co_next = alloc(struct control);
	    ZERO(cend[stackp]->co_next, struct control);
            cend[stackp]->co_next->co_prev = cend[stackp];
            cend[stackp]->co_next->co_parent = 
                    cend[stackp]->co_parent;
            cend[stackp] = cend[stackp]->co_next;
        } else if (!cend[stackp]) {
            control[stackp] = cend[stackp] = alloc(struct control);
	    ZERO(cend[stackp], struct control);
	}

        if (eq(wlist->wl_word, "while")) {
            cend[stackp]->co_type = CO_WHILE;
            cend[stackp]->co_cond = wlist->wl_next;
            if (!cend[stackp]->co_cond) {
                fprintf(stderr,
                    "Error: missing while condition.\n");
            }
            newblock;
        } else if (eq(wlist->wl_word, "dowhile")) {
            cend[stackp]->co_type = CO_DOWHILE;
            cend[stackp]->co_cond = wlist->wl_next;
            if (!cend[stackp]->co_cond) {
                fprintf(stderr,
                    "Error: missing dowhile condition.\n");
            }
            newblock;
        } else if (eq(wlist->wl_word, "repeat")) {
            cend[stackp]->co_type = CO_REPEAT;
            if (!wlist->wl_next) {
                cend[stackp]->co_numtimes = -1;
            } else {
                char *s;
                double *dd;
                wlist = cp_variablesubst(cp_bquote(
                        cp_doglob(wl_copy(wlist))));
                s = wlist->wl_next->wl_word;

                dd = ft_numparse(&s, false);
                if (dd) {
                    if (*dd < 0) {
                        fprintf(cp_err, 
            "Error: can't repeat a negative number of times\n");
                        *dd = 0.0;
                    }
                    cend[stackp]->co_numtimes = (int) *dd;
                } else
                    fprintf(cp_err, 
                    "Error: bad repeat argument %s\n",
                        wlist->wl_next->wl_word);
            }
            newblock;
        } else if (eq(wlist->wl_word, "if")) {
            cend[stackp]->co_type = CO_IF;
            cend[stackp]->co_cond = wlist->wl_next;
            if (!cend[stackp]->co_cond) {
                fprintf(stderr, 
                    "Error: missing if condition.\n");
            }
            newblock;
        } else if (eq(wlist->wl_word, "foreach")) {
            cend[stackp]->co_type = CO_FOREACH;
            if (wlist->wl_next) {
                wlist = wlist->wl_next;
                cend[stackp]->co_foreachvar = 
                        copy(wlist->wl_word);
                wlist = wlist->wl_next;
            } else
                fprintf(stderr, 
                    "Error: missing foreach variable.\n");
            wlist = cp_doglob(wlist);
            cend[stackp]->co_text = wl_copy(wlist);
            newblock;
        } else if (eq(wlist->wl_word, "label")) {
            cend[stackp]->co_type = CO_LABEL;
            if (wlist->wl_next) {
                cend[stackp]->co_text = wl_copy(wlist->wl_next);
                /* I think of everything, don't I? */
                cp_addkword(CT_LABEL, wlist->wl_next->wl_word);
                if (wlist->wl_next->wl_next)
                    fprintf(cp_err, 
                "Warning: ignored extra junk after label.\n");
            } else
                fprintf(stderr, "Error: missing label.\n");
        } else if (eq(wlist->wl_word, "goto")) {
            /* Incidentally, this won't work if the values 1 and
             * 2 ever get to be valid character pointers -- I
             * think it's reasonably safe to assume they aren't...
             */
            cend[stackp]->co_type = CO_GOTO;
            if (wlist->wl_next) {
                cend[stackp]->co_text = wl_copy(wlist->wl_next);
                if (wlist->wl_next->wl_next)
                    fprintf(cp_err, 
                "Warning: ignored extra junk after goto.\n");
            } else
                fprintf(stderr, "Error: missing label.\n");
        } else if (eq(wlist->wl_word, "continue")) {
            cend[stackp]->co_type = CO_CONTINUE;
            if (wlist->wl_next) {
                cend[stackp]->co_numtimes = scannum(wlist->
                        wl_next->wl_word);
                if (wlist->wl_next->wl_next)
                    fprintf(cp_err, 
            "Warning: ignored extra junk after continue %d.\n",
                        cend[stackp]->co_numtimes);
            } else
                cend[stackp]->co_numtimes = 1;
        } else if (eq(wlist->wl_word, "break")) {
            cend[stackp]->co_type = CO_BREAK;
            if (wlist->wl_next) {
                cend[stackp]->co_numtimes = scannum(wlist->
                        wl_next->wl_word);
                if (wlist->wl_next->wl_next)
                    fprintf(cp_err, 
                "Warning: ignored extra junk after break %d.\n",
                        cend[stackp]->co_numtimes);
            } else
                cend[stackp]->co_numtimes = 1;
        } else if (eq(wlist->wl_word, "end")) {
            /* Throw away this thing. */
            if (!cend[stackp]->co_parent) {
                fprintf(stderr, "Error: no block to end.\n");
                cend[stackp]->co_type = CO_UNFILLED;
            } else if (cend[stackp]->co_prev) {
                cend[stackp]->co_prev->co_next = NULL;
                x = cend[stackp];
                cend[stackp] = cend[stackp]->co_parent;
                tfree(x);
            } else {
                x = cend[stackp];
                cend[stackp] = cend[stackp]->co_parent;
                cend[stackp]->co_children = NULL;
                tfree(x);
            }
        } else if (eq(wlist->wl_word, "else")) {
            if (!cend[stackp]->co_parent ||
                    (cend[stackp]->co_parent->co_type !=
                    CO_IF)) {
                fprintf(stderr, "Error: misplaced else.\n");
                cend[stackp]->co_type = CO_UNFILLED;
            } else {
                if (cend[stackp]->co_prev)
                    cend[stackp]->co_prev->co_next = NULL;
                else
                    cend[stackp]->co_parent->co_children =
                            NULL;
                cend[stackp]->co_parent->co_elseblock = 
                        cend[stackp];
                cend[stackp]->co_prev = NULL;
            }
        } else {
            cend[stackp]->co_type = CO_STATEMENT;
            cend[stackp]->co_text = wlist;
        }
        if (!cend[stackp]->co_parent) {
            x = cend[stackp];
            /* We have to toss this do-while loop in here so
             * that gotos at the top level will work.
             */
            do {
                i = doblock(x, &nn);
                switch (*i) {
                    case NORMAL:
                        break;
                    case BROKEN:
                        fprintf(cp_err, 
    "Error: break not in loop or too many break levels given\n");
                        break;
                    case CONTINUED:
                        fprintf(cp_err, 
    "Error: continue not in loop or too many continue levels given\n");
                        break;
                    default:
                        x = findlabel(i, 
                            control[stackp]);
                        if (!x)
                            fprintf(cp_err, 
                        "Error: label %s not found\n",
                                i);
                }
                if (x)
                    x = x->co_next;
            } while (x);
        }
        if (string)
            return (1); /* The return value is irrelevant. */
    }
}

/* Execute a block.  There can be a number of return values from this routine.
 *  NORMAL indicates a normal termination
 *  BROKEN indicates a break -- if the caller is a breakable loop,
 *      terminate it, otherwise pass the break upwards
 *  CONTINUED indicates a continue -- if the caller is a continuable loop,
 *      continue, else pass the continue upwards
 *  Any other return code is considered a pointer to a string which is
 *      a label somewhere -- if this label is present in the block,
 *      goto it, otherwise pass it up. Note that this prevents jumping
 *      into a loop, which is good.
 * Note that here is where we expand variables, ``, and globs for controls.
 * The 'num' argument is used by break n and continue n.
 */

static char *
doblock(bl, num)
    struct control *bl;
    int *num;
{
    struct control *ch, *cn = NULL;
    wordlist *wl;
    char *i;
    int nn;

    switch (bl->co_type) {

        case CO_WHILE:
        while (bl->co_cond && cp_istrue(bl->co_cond)) {
            for (ch = bl->co_children; ch; ch = cn) {
                cn = ch->co_next;
                i = doblock(ch, &nn);
                switch (*i) {

                    case NORMAL:
                    break;

                    case BROKEN:    /* Break. */
                    if (nn < 2)
                        return (NORMAL_STR);
                    else {
                        *num = nn - 1;
                        return (BROKEN_STR);
                    }

                    case CONTINUED: /* Continue. */
                    if (nn < 2) {
                        cn = NULL;
                        break;
                    } else {
                        *num = nn - 1;
                        return (CONTINUED_STR);
                    }

                    default:
                    cn = findlabel(i, bl->co_children);
                    if (!cn)
                        return (i);
                }
            }
        }
        break;

        case CO_DOWHILE:
        do {
            for (ch = bl->co_children; ch; ch = cn) {
                cn = ch->co_next;
                i = doblock(ch, &nn);
                switch (*i) {

                    case NORMAL:
                    break;

                    case BROKEN:    /* Break. */
                    if (nn < 2)
                        return (NORMAL_STR);
                    else {
                        *num = nn - 1;
                        return (BROKEN_STR);
                    }

                    case CONTINUED: /* Continue. */
                    if (nn < 2) {
                        cn = NULL;
                        break;
                    } else {
                        *num = nn - 1;
                        return (CONTINUED_STR);
                    }

                    default:
                    cn = findlabel(i, bl->co_children);
                    if (!cn)
                        return (i);
                }
            }
        } while (bl->co_cond && cp_istrue(bl->co_cond));
        break;

        case CO_REPEAT:
        while ((bl->co_numtimes > 0) ||
                (bl->co_numtimes == -1)) {
            if (bl->co_numtimes != -1)
                bl->co_numtimes--;
            for (ch = bl->co_children; ch; ch = cn) {
                cn = ch->co_next;
                i = doblock(ch, &nn);
                switch (*i) {

                    case NORMAL:
                    break;

                    case BROKEN:    /* Break. */
                    if (nn < 2)
                        return (NORMAL_STR);
                    else {
                        *num = nn - 1;
                        return (BROKEN_STR);
                    }

                    case CONTINUED: /* Continue. */
                    if (nn < 2) {
                        cn = NULL;
                        break;
                    } else {
                        *num = nn - 1;
                        return (CONTINUED_STR);
                    }

                    default:
                    cn = findlabel(i, bl->co_children);
                    if (!cn)
                        return (i);
                }
            }
        }
        break;

        case CO_IF:
        if (bl->co_cond && cp_istrue(bl->co_cond)) {
            for (ch = bl->co_children; ch; ch = cn) {
                cn = ch->co_next;
                i = doblock(ch, &nn);
                if (*i > 2) {
                    cn = findlabel(i,
                        bl->co_children);
                    if (!cn)
                        return (i);
                } else if (*i != NORMAL) {
                    *num = nn;
                    return (i);
                }
            }
        } else {
            for (ch = bl->co_elseblock; ch; ch = cn) {
                cn = ch->co_next;
                i = doblock(ch, &nn);
                if (*i > 2) {
                    cn = findlabel(i,
                        bl->co_elseblock);
                    if (!cn)