vtc.y

使用BorlandC++4.5编译的一个MUD客户端程序

} Token;

Token *tokbuf;
int tokpos = 0, toksize;
#define INIT_TOKENS 128

#define Textend Checkinc(tokbuf, Token, toksize, tokpos)
#define Add_vtoken(t, elem, v) if (1) { Textend; tokbuf[tokpos].type = (t); \
					tokbuf[tokpos++].val.elem = (v); } else
#define Add_ntoken(t) if (1) { Textend; tokbuf[tokpos++].type = (t); } else

#define INIT_SCONST 32
#define INIT_IDENTS 64
static Cstr *sconsts;			/* Allocated string constants */
static char **idents;			/* Allocated identifiers */
static int sconstpos = 0, identpos = 0, sconstsize, identsize;
static int braces = 0, incomment = 0, instring = 0, infunc = 0, tokindex;
static String sbuf;

static char *ecodes = "ntvbrf\\'\"";
static char *results = "\n\t\v\b\r\f\\'\"";
static int begin[128], end[128];	/* Lookup table for words */
static char transtab[128];		/* Table for escape codes */
/* Table of reserved words and compound operators */
/* These do not need to be in alphabetical order, but words with the
** same first character must be adjacent.  Among compound operators
** with the same first character, longer operators should come first. */
static struct word {
	char *s;
	int val;
} words[] = {
	{ ""		, 0		},
	{ "do"		, DO		},
	{ "while"	, WHILE		},
	{ "if"		, IF		},
	{ "else"	, ELSE		},
	{ "for"		, FOR		},
	{ "func"	, FUNC		},
	{ "goto"	, GOTO		},
	{ "break"	, BREAK		},
	{ "continue"	, CONTINUE	},
	{ "return"	, RETURN	},
	{ "^="		, BXA		},
	{ "*="		, TA		},
	{ "/="		, DA		},
	{ "%="		, MA		},
	{ "+="		, AA		},
	{ "++"		, INC		},
	{ "-="		, SA		},
	{ "-->"		, FASSIGN	},
	{ "--"		, DEC		},
	{ "->"		, DEREF		},
	{ "<<="		, SLA		},
	{ "<<"		, SL		},
	{ "<="		, LE		},
	{ ">>="		, SRA		},
	{ ">>"		, SR		},
	{ ">="		, GE		},
	{ "&="		, BAA		},
	{ "&&"		, AND		},
	{ "|="		, BOA		},
	{ "||"		, OR		},
	{ "=="		, EQ		},
	{ "!="		, NE		},
	{ "?:="		, CONDA		},
	{ ""		, 0		}
};

#define NWORDS (sizeof(words) / sizeof(struct word) - 1)

/* Set up data */
void init_compile()
{
	int i;

	bzero(begin, sizeof(begin));
	bzero(end, sizeof(end));
	for (i = 0; i < NWORDS; i++) {
		begin[*words[i].s] = i;
		while (*words[i + 1].s == *words[i].s)
			i++;
		end[*words[i].s] = i;
	}
	bzero(transtab, sizeof(transtab));
	for (i = 0; ecodes[i]; i++)
		transtab[ecodes[i]] = results[i];
	tokbuf = Newarray(Token, toksize = INIT_TOKENS);
	icode = Newarray(Instr, codesize = INIT_CODE);
	sconsts = Newarray(Cstr, sconstsize = INIT_SCONST);
	idents = Newarray(char *, identsize = INIT_IDENTS);
	jmptab = Newarray(int, jmpsize = INIT_JMP);
	condstack = Newarray(int, condsize = INIT_COND);
	loopstack = Newarray(int, loopsize = INIT_COND);
	sbuf = empty_string;
}

/* Analyze text and place tokens in buffer */

void parse(text)
	char *text;
{
	while (*text) {
		text = parse_token(text);
		if (!text)
			return;
	}
	if (!infunc && !braces && !incomment && !instring && tokpos)
		compile();
}

static char *parse_token(s)
	char *s;
{
	char *ptr, buf[MAXILEN + 1];
	int i;
	void (*bobj)();
	Const *cp;

	if (incomment)
		return read_comment(s);
	if (instring)
		return read_string(s);
	for (; isspace(*s); s++);
	if (!*s || *s == '/' && s[1] == '/')
		return "";
	if (*s == '/' && s[1] == '*')
		return read_comment(s + 2);
	if (*s == '"') {
		s_term(&sbuf, 0);
		return read_string(s + 1);
	}
	if (*s == '\'') {
		s++;
		Add_vtoken(ICONST, num, read_char(&s));
		if (*s++ != '\'')
			lexerror(ERR_UNTERMCHAR);
		return s;
	}
	if (isdigit(*s)) {
		i = 0;
		if (*s == '0' && lcase(s[1]) == 'x' && isxdigit(s[2])) {
			s++;
			while (isxdigit(*++s))
				i = i * 0x10 + Hexdigitvalue(*s);
			Add_vtoken(ICONST, num, i);
			return s;
		}
		if (*s == '0' && s[1] >= '0' && s[1] <= '8') {
			while (*++s >= '0' && *s <= '8')
				i = i * 010 + *s - '0';
			Add_vtoken(ICONST, num, i);
			return s;
		}
		Add_vtoken(ICONST, num, atoi(s));
		while (isdigit(*++s));
		return s;
	}
	if (*s == '\\' && !s[1])
		return NULL;
	if (isalpha(*s) || *s == '_') {
		for (ptr = s; isalnum(*ptr) || *ptr == '_'; ptr++);
		strncpy(buf, s, min(ptr - s, MAXILEN));
		buf[min(ptr - s, MAXILEN)] = '\0';
		if (!(*buf & ~0x7f) && begin[*buf]) {
			for (i = begin[*buf]; i <= end[*buf]; i++) {
				if (streq(buf + 1, words[i].s + 1))
					break;
			}
			if (i <= end[*buf]) {
				if (words[i].val == FUNC) {
					if (tokpos) {
						lexerror(ERR_ILLFUNC);
						braces = 0;
					}
					infunc = 1;
				}
				Add_ntoken(words[i].val);
				return ptr;
			}
		}
		bobj = find_bobj(buf);
		if (bobj) {
			Add_vtoken(BOBJ, bobj, bobj);
			return ptr;
		}
		cp = find_const(buf);
		if (cp) {
			Add_vtoken(ICONST, num, cp->val);
			return ptr;
		}
		Push(idents, char *, identsize, identpos, vtstrdup(buf));
		Add_vtoken(IDENT, s, idents[identpos - 1]);
		return ptr;
	}
	if (!(*s & ~0x7f) && begin[*s]) {
		for (i = begin[*s]; i <= end[*s]; i++) {
			if (!strncmp(s + 1, words[i].s + 1,
				     strlen(words[i].s) - 1))
				break;
		}
		if (i <= end[*s]) {
			Add_ntoken(words[i].val);
			if (words[i].val == FASSIGN)
				infunc = 0;
			return s + strlen(words[i].s);
		}
	}
	Add_ntoken(*s);
	if (*s == '{')
		braces++;
	else if (*s == '}') {
		if (!braces)
			lexerror(ERR_BADBRACE);
		else if (!--braces)
			infunc = 0;
	}
	return s + 1;
}

static int read_char(s)
	char **s;
{
	char c;
	int val = 0, count;

	if (**s != '\\')
		return *(*s)++;
	c = transtab[*++(*s) & 0x7f];
	if (c) {
		(*s)++;
		return c;
	}
	if (**s < '0' || **s > '8')
		return '\\';
	for (count = 0; count < 3 && **s >= '0' && **s <= '8'; (*s)++)
		val = val * 8 + **s - '0';
	return val;
}

static int enter_sconst(c)
	Cstr c;
{
	Push(sconsts, Cstr, sconstsize, sconstpos, cstr_c(c));
	return sconstpos - 1;
}

static char *read_string(s)
	char *s;
{
	while (*s && *s != '"') {
		if (*s == '\\' && !s[1]) {
			instring = 1;
			return "";
		}
		s_fadd(&sbuf, read_char(&s));
	}
	if (!*s) {
		lexerror(ERR_UNTERMSTR);
		return "";
	}
	instring = 0;
	Add_vtoken(SCONST, str, enter_sconst(sbuf.c));
	return s + 1;
}

static char *read_comment(s)
	char *s;
{
	s = strchr(s, '*');
	while (s) {
		if (s[1] == '/') {
			incomment = 0;
			return s + 2;
		}
		s = strchr(s + 1, '*');
	}
	incomment = 1;
	return "";
}

static void compile()
{
	tokindex = 0;
	yyparse();
	if (!errflag) {
		scan();
		return;
	}
	while (yylex());
	condpos = looppos = 0;
	cleanup_parse();
}

static void scan()
{
	Prog *newprog;
	Instr *in, *end;
	char *s;
	Func *func;
	String dtext;

	dtext = empty_string;
	jmptab[0] = loc;
	Code(I_STOP);
	newprog = New(Prog);
	newprog->refs = 0;
	newprog->avarc = avarc;
	newprog->reqargs = reqargs;
	newprog->lvarc = lvarc;
	newprog->code = Newarray(Instr, loc);
	Copy(icode, newprog->code, loc, Instr);
	end = newprog->code + loc;
	for (in = newprog->code; in < end; in += iwidth[in->type]) {
		switch(in->type) {
		    case I_SCONST:
			in[1].sconst = add_sconst(&sconsts[in[1].sindex]);
		    Case I_FCALL:
			s = in[2].ident;
			func = find_func(s);
			if (debug && (!func || !func->cmd)
			    && !strstr(dtext.c.s, s)) {
				s_acat(&dtext, " ");
				s_acat(&dtext, s);
				s_acat(&dtext, "()");
			}
			in[2].func = func ? func : add_func(s, NULL);
		    Case I_FPTR:
			s = in[1].ident;
			func = find_func(s);
			if (debug && (!func || !func->cmd)
			    && !strstr(dtext.c.s, s)) {
				s_acat(&dtext, " .");
				s_acat(&dtext, s);
			}
			in[1].func = func ? func : add_func(s, NULL);
		    Case I_GVAR:
			if (debug && !strstr(dtext.c.s, in[1].ident)) {
				s_acat(&dtext, " ");
				s_acat(&dtext, in[1].ident);
			}
			in[1].tnum = get_vindex(in[1].ident);
		    Case I_JMP:
		    case I_JMPT:
		    case I_JMPF:
		    case I_JMPPT:
		    case I_JMPPF:
			in[1].loc = newprog->code + jmptab[in[1].offset];
		}
	}
	if (debug && *dtext.c.s) {
		if (*curfile)
			outputf("%s ", curfile);
		outputf("%s:%s\n", *curfunc ? curfunc : "Command",
			dtext.c.s);
	}
	s_free(&dtext);
	if (*curfunc) {
		add_func(curfunc, newprog);
		cleanup_parse();
	} else {
		cleanup_parse();
		run_prog(newprog);
	}
}

static void cleanup_parse()
{
	while (identpos--)
		Discardstring(idents[identpos]);
	while (sconstpos--) {
		if (sconsts[sconstpos].s)
			Discardarray(sconsts[sconstpos].s, char,
				     sconsts[sconstpos].l + 1);
	}
	free_labels();
	curfunc = "";
	tokpos = loc = lvarc = avarc = errflag = identpos = sconstpos = 0;
	reqargs = 0;
	jmppos = 1;
}

static void lexerror(s)
	char *s;
{
	if (lexline != -1)
		outputf("%s line %d: ", curfile, lexline);
	outputf("%s\n", s);
	errflag = 1;
}

static void yyerror(msg)
	char *msg;
{
	if (parseline != -1)
		outputf("%s line %d: ", curfile, parseline);
	coutput(msg);
	if (*curfunc)
		outputf(" in function %s", curfunc);
	coutput("\n");
	errflag = 1;
}

static int yylex()
{
	while (tokindex < tokpos && tokbuf[tokindex].type == '\n') {
		tokindex++;
		if (parseline != -1)
			parseline++;
	}
	if (tokindex < tokpos) {
		yylval = tokbuf[tokindex].val;
		return tokbuf[tokindex++].type;
	}
	return 0;
}

int load_file(name)
	char *name;
{
	int olline, opline;
	char *ocfile;
	FILE *fp;
	String freader;

	freader = empty_string;
	fp = fopen(expand(name), "r");
	if (!fp)
		return -1;
	olline = lexline;
	opline = parseline;
	ocfile = curfile;
	lexline = parseline = 1;
	curfile = vtstrdup(name);
	while (s_fget(&freader, fp)) {
		if (freader.c.s[freader.c.l - 1] == '\n')
			freader.c.s[freader.c.l - 1] = '\0';
		parse(freader.c.s);
		if (tokpos)
			Add_ntoken('\n');
		else
			parseline++;
		lexline++;
	}
	lexline = olline;
	parseline = opline;
	Discardstring(curfile);
	curfile = ocfile;
	fclose(fp);
	s_free(&freader);
	return 0;
}