walk.c

早期freebsd实现

/* $RCSfile: walk.c,v $$Revision: 4.0.1.3 $$Date: 92/06/08 17:33:46 $
 *
 *    Copyright (c) 1991, Larry Wall
 *
 *    You may distribute under the terms of either the GNU General Public
 *    License or the Artistic License, as specified in the README file.
 *
 * $Log:	walk.c,v $
 * Revision 4.0.1.3  92/06/08  17:33:46  lwall
 * patch20: in a2p, simplified the filehandle model
 * patch20: in a2p, made RS="" translate to $/ = "\n\n"
 * patch20: in a2p, do {...} while ... was missing some reconstruction code
 * patch20: in a2p, getline should allow variable to be array element
 * 
 * Revision 4.0.1.2  91/11/05  19:25:09  lwall
 * patch11: in a2p, split on whitespace produced extra null field
 * 
 * Revision 4.0.1.1  91/06/07  12:22:04  lwall
 * patch4: new copyright notice
 * patch4: a2p didn't correctly implement -n switch
 * 
 * Revision 4.0  91/03/20  01:58:36  lwall
 * 4.0 baseline.
 * 
 */

#include "handy.h"
#include "EXTERN.h"
#include "util.h"
#include "a2p.h"

bool exitval = FALSE;
bool realexit = FALSE;
bool saw_getline = FALSE;
bool subretnum = FALSE;
bool saw_FNR = FALSE;
bool saw_argv0 = FALSE;
bool saw_fh = FALSE;
int maxtmp = 0;
char *lparen;
char *rparen;
char *limit;
STR *subs;
STR *curargs = Nullstr;

STR *
walk(useval,level,node,numericptr,minprec)
int useval;
int level;
register int node;
int *numericptr;
int minprec;			/* minimum precedence without parens */
{
    register int len;
    register STR *str;
    register int type;
    register int i;
    register STR *tmpstr;
    STR *tmp2str;
    STR *tmp3str;
    char *t;
    char *d, *s;
    int numarg;
    int numeric = FALSE;
    STR *fstr;
    int prec = P_MAX;		/* assume no parens needed */
    char *index();

    if (!node) {
	*numericptr = 0;
	return str_make("");
    }
    type = ops[node].ival;
    len = type >> 8;
    type &= 255;
    switch (type) {
    case OPROG:
	arymax = 0;
	if (namelist) {
	    while (isalpha(*namelist)) {
		for (d = tokenbuf,s=namelist;
		  isalpha(*s) || isdigit(*s) || *s == '_';
		  *d++ = *s++) ;
		*d = '\0';
		while (*s && !isalpha(*s)) s++;
		namelist = s;
		nameary[++arymax] = savestr(tokenbuf);
	    }
	}
	if (maxfld < arymax)
	    maxfld = arymax;
	opens = str_new(0);
	subs = str_new(0);
	str = walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	if (do_split && need_entire && !absmaxfld)
	    split_to_array = TRUE;
	if (do_split && split_to_array)
	    set_array_base = TRUE;
	if (set_array_base) {
	    str_cat(str,"$[ = 1;\t\t\t# set array base to 1\n");
	}
	if (fswitch && !const_FS)
	    const_FS = fswitch;
	if (saw_FS > 1 || saw_RS)
	    const_FS = 0;
	if (saw_ORS && need_entire)
	    do_chop = TRUE;
	if (fswitch) {
	    str_cat(str,"$FS = '");
	    if (index("*+?.[]()|^$\\",fswitch))
		str_cat(str,"\\");
	    sprintf(tokenbuf,"%c",fswitch);
	    str_cat(str,tokenbuf);
	    str_cat(str,"';\t\t# field separator from -F switch\n");
	}
	else if (saw_FS && !const_FS) {
	    str_cat(str,"$FS = ' ';\t\t# set field separator\n");
	}
	if (saw_OFS) {
	    str_cat(str,"$, = ' ';\t\t# set output field separator\n");
	}
	if (saw_ORS) {
	    str_cat(str,"$\\ = \"\\n\";\t\t# set output record separator\n");
	}
	if (saw_argv0) {
	    str_cat(str,"$ARGV0 = $0;\t\t# remember what we ran as\n");
	}
	if (str->str_cur > 20)
	    str_cat(str,"\n");
	if (ops[node+2].ival) {
	    str_scat(str,fstr=walk(0,level,ops[node+2].ival,&numarg,P_MIN));
	    str_free(fstr);
	    str_cat(str,"\n\n");
	}
	fstr = walk(0,level+1,ops[node+3].ival,&numarg,P_MIN);
	if (*fstr->str_ptr) {
	    if (saw_line_op)
		str_cat(str,"line: ");
	    str_cat(str,"while (<>) {\n");
	    tab(str,++level);
	    if (saw_FS && !const_FS)
		do_chop = TRUE;
	    if (do_chop) {
		str_cat(str,"chop;\t# strip record separator\n");
		tab(str,level);
	    }
	    if (do_split)
		emit_split(str,level);
	    str_scat(str,fstr);
	    str_free(fstr);
	    fixtab(str,--level);
	    str_cat(str,"}\n");
	    if (saw_FNR)
		str_cat(str,"continue {\n    $FNRbase = $. if eof;\n}\n");
	}
	else
	    str_cat(str,"while (<>) { }		# (no line actions)\n");
	if (ops[node+4].ival) {
	    realexit = TRUE;
	    str_cat(str,"\n");
	    tab(str,level);
	    str_scat(str,fstr=walk(0,level,ops[node+4].ival,&numarg,P_MIN));
	    str_free(fstr);
	    str_cat(str,"\n");
	}
	if (exitval)
	    str_cat(str,"exit $ExitValue;\n");
	if (subs->str_ptr) {
	    str_cat(str,"\n");
	    str_scat(str,subs);
	}
	if (saw_getline) {
	    for (len = 0; len < 4; len++) {
		if (saw_getline & (1 << len)) {
		    sprintf(tokenbuf,"\nsub Getline%d {\n",len);
		    str_cat(str, tokenbuf);
		    if (len & 2) {
			if (do_fancy_opens)
			    str_cat(str,"    &Pick('',@_);\n");
			else
			    str_cat(str,"    ($fh) = @_;\n");
		    }
		    else {
			if (saw_FNR)
			    str_cat(str,"    $FNRbase = $. if eof;\n");
		    }
		    if (len & 1)
			str_cat(str,"    local($_);\n");
		    if (len & 2)
			str_cat(str,
			  "    if ($getline_ok = (($_ = <$fh>) ne ''))");
		    else
			str_cat(str,
			  "    if ($getline_ok = (($_ = <>) ne ''))");
		    str_cat(str, " {\n");
		    level += 2;
		    tab(str,level);
		    i = 0;
		    if (do_chop) {
			i++;
			str_cat(str,"chop;\t# strip record separator\n");
			tab(str,level);
		    }
		    if (do_split && !(len & 1)) {
			i++;
			emit_split(str,level);
		    }
		    if (!i)
			str_cat(str,";\n");
		    fixtab(str,--level);
		    str_cat(str,"}\n    $_;\n}\n");
		    --level;
		}
	    }
	}
	if (do_fancy_opens) {
	    str_cat(str,"\n\
sub Pick {\n\
    local($mode,$name,$pipe) = @_;\n\
    $fh = $name;\n\
    open($name,$mode.$name.$pipe) unless $opened{$name}++;\n\
}\n\
");
	}
	break;
    case OHUNKS:
	str = walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	str_scat(str,fstr=walk(0,level,ops[node+2].ival,&numarg,P_MIN));
	str_free(fstr);
	if (len == 3) {
	    str_scat(str,fstr=walk(0,level,ops[node+3].ival,&numarg,P_MIN));
	    str_free(fstr);
	}
	else {
	}
	break;
    case ORANGE:
	prec = P_DOTDOT;
	str = walk(1,level,ops[node+1].ival,&numarg,prec+1);
	str_cat(str," .. ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	break;
    case OPAT:
	goto def;
    case OREGEX:
	str = str_new(0);
	str_set(str,"/");
	tmpstr=walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	/* translate \nnn to [\nnn] */
	for (s = tmpstr->str_ptr, d = tokenbuf; *s; s++, d++) {
	    if (*s == '\\' && isdigit(s[1]) && isdigit(s[2]) && isdigit(s[3])){
		*d++ = '[';
		*d++ = *s++;
		*d++ = *s++;
		*d++ = *s++;
		*d++ = *s;
		*d = ']';
	    }
	    else
		*d = *s;
	}
	*d = '\0';
	for (d=tokenbuf; *d; d++)
	    *d += 128;
	str_cat(str,tokenbuf);
	str_free(tmpstr);
	str_cat(str,"/");
	break;
    case OHUNK:
	if (len == 1) {
	    str = str_new(0);
	    str = walk(0,level,oper1(OPRINT,0),&numarg,P_MIN);
	    str_cat(str," if ");
	    str_scat(str,fstr=walk(0,level,ops[node+1].ival,&numarg,P_MIN));
	    str_free(fstr);
	    str_cat(str,";");
	}
	else {
	    tmpstr = walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	    if (*tmpstr->str_ptr) {
		str = str_new(0);
		str_set(str,"if (");
		str_scat(str,tmpstr);
		str_cat(str,") {\n");
		tab(str,++level);
		str_scat(str,fstr=walk(0,level,ops[node+2].ival,&numarg,P_MIN));
		str_free(fstr);
		fixtab(str,--level);
		str_cat(str,"}\n");
		tab(str,level);
	    }
	    else {
		str = walk(0,level,ops[node+2].ival,&numarg,P_MIN);
	    }
	}
	break;
    case OPPAREN:
	str = str_new(0);
	str_set(str,"(");
	str_scat(str,fstr=walk(useval != 0,level,ops[node+1].ival,&numarg,P_MIN));
	str_free(fstr);
	str_cat(str,")");
	break;
    case OPANDAND:
	prec = P_ANDAND;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," && ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec+1));
	str_free(fstr);
	break;
    case OPOROR:
	prec = P_OROR;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," || ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec+1));
	str_free(fstr);
	break;
    case OPNOT:
	prec = P_UNARY;
	str = str_new(0);
	str_set(str,"!");
	str_scat(str,fstr=walk(1,level,ops[node+1].ival,&numarg,prec));
	str_free(fstr);
	break;
    case OCOND:
	prec = P_COND;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," ? ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	str_cat(str," : ");
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec+1));
	str_free(fstr);
	break;
    case OCPAREN:
	str = str_new(0);
	str_set(str,"(");
	str_scat(str,fstr=walk(useval != 0,level,ops[node+1].ival,&numarg,P_MIN));
	str_free(fstr);
	numeric |= numarg;
	str_cat(str,")");
	break;
    case OCANDAND:
	prec = P_ANDAND;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	numeric = 1;
	str_cat(str," && ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec+1));
	str_free(fstr);
	break;
    case OCOROR:
	prec = P_OROR;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	numeric = 1;
	str_cat(str," || ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec+1));
	str_free(fstr);
	break;
    case OCNOT:
	prec = P_UNARY;
	str = str_new(0);
	str_set(str,"!");
	str_scat(str,fstr=walk(1,level,ops[node+1].ival,&numarg,prec));
	str_free(fstr);
	numeric = 1;
	break;
    case ORELOP:
	prec = P_REL;
	str = walk(1,level,ops[node+2].ival,&numarg,prec+1);
	numeric |= numarg;
	tmpstr = walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	tmp2str = walk(1,level,ops[node+3].ival,&numarg,prec+1);
	numeric |= numarg;
	if (!numeric ||
	 (!numarg && (*tmp2str->str_ptr == '"' || *tmp2str->str_ptr == '\''))) {
	    t = tmpstr->str_ptr;
	    if (strEQ(t,"=="))
		str_set(tmpstr,"eq");
	    else if (strEQ(t,"!="))
		str_set(tmpstr,"ne");
	    else if (strEQ(t,"<"))
		str_set(tmpstr,"lt");
	    else if (strEQ(t,"<="))
		str_set(tmpstr,"le");
	    else if (strEQ(t,">"))
		str_set(tmpstr,"gt");
	    else if (strEQ(t,">="))
		str_set(tmpstr,"ge");
	    if (!index(tmpstr->str_ptr,'\'') && !index(tmpstr->str_ptr,'"') &&
	      !index(tmp2str->str_ptr,'\'') && !index(tmp2str->str_ptr,'"') )
		numeric |= 2;
	}
	if (numeric & 2) {
	    if (numeric & 1)		/* numeric is very good guess */
		str_cat(str," ");
	    else
		str_cat(str,"\377");
	    numeric = 1;
	}
	else
	    str_cat(str," ");
	str_scat(str,tmpstr);
	str_free(tmpstr);
	str_cat(str," ");
	str_scat(str,tmp2str);
	str_free(tmp2str);
	numeric = 1;
	break;
    case ORPAREN:
	str = str_new(0);
	str_set(str,"(");
	str_scat(str,fstr=walk(useval != 0,level,ops[node+1].ival,&numarg,P_MIN));
	str_free(fstr);
	numeric |= numarg;
	str_cat(str,")");
	break;
    case OMATCHOP:
	prec = P_MATCH;
	str = walk(1,level,ops[node+2].ival,&numarg,prec+1);
	str_cat(str," ");
	tmpstr = walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	if (strEQ(tmpstr->str_ptr,"~"))
	    str_cat(str,"=~");
	else {
	    str_scat(str,tmpstr);
	    str_free(tmpstr);
	}
	str_cat(str," ");
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec+1));
	str_free(fstr);
	numeric = 1;
	break;
    case OMPAREN:
	str = str_new(0);
	str_set(str,"(");
	str_scat(str,
	  fstr=walk(useval != 0,level,ops[node+1].ival,&numarg,P_MIN));
	str_free(fstr);
	numeric |= numarg;
	str_cat(str,")");
	break;
    case OCONCAT:
	prec = P_ADD;
	type = ops[ops[node+1].ival].ival & 255;
	str = walk(1,level,ops[node+1].ival,&numarg,prec+(type != OCONCAT));
	str_cat(str," . ");
	type = ops[ops[node+2].ival].ival & 255;
	str_scat(str,
	  fstr=walk(1,level,ops[node+2].ival,&numarg,prec+(type != OCONCAT)));
	str_free(fstr);
	break;
    case OASSIGN:
	prec = P_ASSIGN;
	str = walk(0,level,ops[node+2].ival,&numarg,prec+1);
	str_cat(str," ");
	tmpstr = walk(0,level,ops[node+1].ival,&numarg,P_MIN);
	str_scat(str,tmpstr);
	if (str_len(tmpstr) > 1)
	    numeric = 1;
	str_free(tmpstr);
	str_cat(str," ");
	str_scat(str,fstr=walk(1,level,ops[node+3].ival,&numarg,prec));
	str_free(fstr);
	numeric |= numarg;
	if (strEQ(str->str_ptr,"$/ = ''"))
	    str_set(str, "$/ = \"\\n\\n\"");
	break;
    case OADD:
	prec = P_ADD;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," + ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	numeric = 1;
	break;
    case OSUBTRACT:
	prec = P_ADD;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," - ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	numeric = 1;
	break;
    case OMULT:
	prec = P_MUL;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," * ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	numeric = 1;
	break;
    case ODIV:
	prec = P_MUL;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," / ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));
	str_free(fstr);
	numeric = 1;
	break;
    case OPOW:
	prec = P_POW;
	str = walk(1,level,ops[node+1].ival,&numarg,prec+1);
	str_cat(str," ** ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec));
	str_free(fstr);
	numeric = 1;
	break;
    case OMOD:
	prec = P_MUL;
	str = walk(1,level,ops[node+1].ival,&numarg,prec);
	str_cat(str," % ");
	str_scat(str,fstr=walk(1,level,ops[node+2].ival,&numarg,prec+1));