Implementation of the local builtin with support for dynamic local scopes

src/cmd/ksh93/bltins/cflow.c

@@ -44,7 +44,7 @@
 int	b_return(int n, char *argv[],Shbltin_t *context)
 {
 	/* 'return' outside of function, dotscript and profile behaves like 'exit' */
-	char do_exit = **argv=='e' || sh.fn_depth==0 && sh.dot_depth==0 && !sh_isstate(SH_PROFILE);
+	char do_exit = **argv=='e' || !sh.infunction && !sh_isstate(SH_PROFILE);
 	NOT_USED(context);
 	while((n = optget(argv, **argv=='e' ? sh_optexit : sh_optreturn))) switch(n)
 	{

src/cmd/ksh93/bltins/misc.c

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1982-2012 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2023 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2024 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 2.0                  *
 *                                                                      *
@@ -56,8 +56,6 @@
 #include	<times.h>
 #endif
 
-#define DOTMAX	MAXDEPTH	/* maximum level of . nesting */
-
 /*
  * Handler function for nv_scan() that unsets a variable's export attribute
  */
@@ -215,16 +213,17 @@ int    b_eval(int argc,char *argv[], Shbltin_t *context)
 #endif
 int    b_dot_cmd(int n,char *argv[],Shbltin_t *context)
 {
-	char *script;
-	Namval_t *np;
-	int jmpval;
-	struct sh_scoped savst, *prevscope = sh.st.self;
-	char *filename=0, *buffer=0, *tofree;
-	int	fd;
-	struct dolnod   *saveargfor;
-	volatile struct dolnod   *argsave=0;
-	struct checkpt buff;
-	Sfio_t *iop=0;
+	char			*script;
+	Namval_t		*np;
+	struct sh_scoped	savst, *prevscope = sh.st.self;
+	char			*filename=0, *buffer=0, *tofree;
+	int			fd, dtret, jmpval, save_invoc_local;
+	char			save_infunction = -1;
+	struct dolnod		*saveargfor;
+	volatile struct dolnod	*argsave=0;
+	struct checkpt		buff;
+	Sfio_t			*iop=0;
+	Namval_t		*nspace = sh.namespace;
 	NOT_USED(context);
 	while (n = optget(argv,sh_optdot)) switch (n)
 	{
@@ -242,61 +241,61 @@ int    b_dot_cmd(int n,char *argv[],Shbltin_t *context)
 		errormsg(SH_DICT,ERROR_usage(2),"%s",optusage(NULL));
 		UNREACHABLE();
 	}
-	if(sh.dot_depth >= DOTMAX)
+	if(sh.dot_depth >= MAXDEPTH)
 	{
 		errormsg(SH_DICT,ERROR_exit(1),e_toodeep,script);
 		UNREACHABLE();
 	}
-	if(!(np=sh.posix_fun))
+	/* check for KornShell style function first */
+	np = nv_search(script,sh.fun_tree,0);
+	if(np && is_afunction(np) && !nv_isattr(np,NV_FPOSIX) && !(sh_isoption(SH_POSIX) && sh.bltindata.bnode==SYSDOT))
 	{
-		/* check for KornShell style function first */
-		np = nv_search(script,sh.fun_tree,0);
-		if(np && is_afunction(np) && !nv_isattr(np,NV_FPOSIX) && !(sh_isoption(SH_POSIX) && sh.bltindata.bnode==SYSDOT))
+		if(!np->nvalue.ip)
 		{
-			if(!np->nvalue.ip)
+			path_search(script,NULL,0);
+			if(np->nvalue.ip)
 			{
-				path_search(script,NULL,0);
-				if(np->nvalue.ip)
-				{
-					if(nv_isattr(np,NV_FPOSIX))
-						np = 0;
-				}
-				else
-				{
-					errormsg(SH_DICT,ERROR_exit(1),e_found,script);
-					UNREACHABLE();
-				}
+				if(nv_isattr(np,NV_FPOSIX))
+					np = 0;
 			}
-		}
-		else
-			np = 0;
-		if(!np)
-		{
-			if((fd=path_open(script,path_get(script))) < 0)
+			else
 			{
-				errormsg(SH_DICT,ERROR_system(1),e_open,script);
+				errormsg(SH_DICT,ERROR_exit(1),e_found,script);
 				UNREACHABLE();
 			}
-			filename = path_fullname(stkptr(sh.stk,PATH_OFFSET));
 		}
 	}
+	else
+		np = 0;
+	if(!np)
+	{
+		/* Open the dot script */
+		if((fd=path_open(script,path_get(script))) < 0)
+		{
+			errormsg(SH_DICT,ERROR_system(1),e_open,script);
+			UNREACHABLE();
+		}
+		filename = path_fullname(stkptr(sh.stk,PATH_OFFSET));
+	}
+	else
+	{
+		/* We are executing a KornShell function as a dot script */
+		save_infunction = sh.infunction;
+		sh.infunction = FUN_KSHDOT;
+	}
 	*prevscope = sh.st;
-	sh.st.lineno = np?((struct functnod*)nv_funtree(np))->functline:1;
+	sh.st.lineno = np ? ((struct functnod*)nv_funtree(np))->functline : 1;
 	sh.st.save_tree = sh.var_tree;
 	if(filename)
-	{
 		sh.st.filename = filename;
-		sh.st.lineno = 1;
-	}
 	sh.st.prevst = prevscope;
 	sh.st.self = &savst;
 	sh.topscope = (Shscope_t*)sh.st.self;
 	prevscope->save_tree = sh.var_tree;
 	tofree = sh.st.filename;
 	if(np)
 		sh.st.filename = np->nvalue.rp->fname;
-	nv_putval(SH_PATHNAMENOD, sh.st.filename ,NV_NOFREE);
-	sh.posix_fun = 0;
+	nv_putval(SH_PATHNAMENOD,sh.st.filename,NV_NOFREE);
 	if(np || argv[1])
 		argsave = sh_argnew(argv,&saveargfor);
 	sh_pushcontext(&buff,SH_JMPDOT);
@@ -308,9 +307,11 @@ int    b_dot_cmd(int n,char *argv[],Shbltin_t *context)
 		sh.dot_depth++;
 		update_sh_level();
 		if(np)
+			/* Execute the function as though it were a dot script */
 			sh_exec((Shnode_t*)(nv_funtree(np)),sh_isstate(SH_ERREXIT));
 		else
 		{
+			/* Run the dot script */
 			buffer = sh_malloc(IOBSIZE+1);
 			iop = sfnew(NULL,buffer,IOBSIZE,fd,SF_READ);
 			sh_offstate(SH_NOFORK);
@@ -331,12 +332,14 @@ int    b_dot_cmd(int n,char *argv[],Shbltin_t *context)
 		prevscope->dolc = sh.st.dolc;
 		prevscope->dolv = sh.st.dolv;
 	}
-	if (sh.st.self != &savst)
+	if(sh.st.self != &savst)
 		*sh.st.self = sh.st;
-	/* only restore the top Shscope_t portion for POSIX functions */
+	if(save_infunction != -1)
+		sh.infunction = save_infunction;
+	/* Only restore the top Shscope_t portion for functions */
 	memcpy(&sh.st, prevscope, sizeof(Shscope_t));
 	sh.topscope = (Shscope_t*)prevscope;
-	nv_putval(SH_PATHNAMENOD, sh.st.filename ,NV_NOFREE);
+	nv_putval(SH_PATHNAMENOD,sh.st.filename,NV_NOFREE);
 	if(jmpval && jmpval!=SH_JMPFUN)
 		siglongjmp(*sh.jmplist,jmpval);
 	return sh.exitval;

src/cmd/ksh93/bltins/typeset.c

@@ -21,6 +21,8 @@
  * export [-p] [arg...]
  * readonly [-p] [arg...]
  * typeset [options] [arg...]
+ * declare [options] [arg...]
+ * local [options] [arg...]
  * autoload [options] [arg...]
  * compound [options] [arg...]
  * float [options] [arg...]
@@ -208,6 +210,7 @@ int    b_alias(int argc,char *argv[],Shbltin_t *context)
     /* for the dictionary generator */
     int    b_autoload(int argc,char *argv[],Shbltin_t *context){}
     int    b_compound(int argc,char *argv[],Shbltin_t *context){}
+    int    b_declare(int argc,char *argv[],Shbltin_t *context){}
     int    b_float(int argc,char *argv[],Shbltin_t *context){}
     int    b_functions(int argc,char *argv[],Shbltin_t *context){}
     int    b_integer(int argc,char *argv[],Shbltin_t *context){}
@@ -221,17 +224,19 @@ int    b_typeset(int argc,char *argv[],Shbltin_t *context)
 	const char	*optstring = sh_opttypeset;
 	Namdecl_t 	*ntp = (Namdecl_t*)context->ptr;
 	Dt_t		*troot;
-	int		isfloat=0, isadjust=0, shortint=0, sflag=0;
+	int		isfloat=0, isadjust=0, shortint=0, sflag=0, local, declare, scoping_flags = 0;
 
 	memset(&tdata,0,sizeof(tdata));
 	troot = sh.var_tree;
+	declare = argv[0][0] == 'd';
+	local = argv[0][0] == 'l';
 	if(ntp)					/* type declaration command added using 'typeset -T' or 'enum' */
 	{
 		tdata.tp = ntp->tp;
 		opt_info.disc = (Optdisc_t*)ntp->optinfof;
 		optstring = ntp->optstring;
 	}
-	else if(argv[0][0] != 't')		/* not <t>ypeset */
+	else if(argv[0][0] != 't' && !declare && !local) /* not <t>ypeset, <d>eclare or <l>ocal */
 	{
 		char **new_argv = (char **)stkalloc(sh.stk, (argc + 2) * sizeof(char*));
 		error_info.id = new_argv[0] = SYSTYPESET->nvname;
@@ -430,7 +435,19 @@ int    b_typeset(int argc,char *argv[],Shbltin_t *context)
 				flag |= (NV_EXPORT|NV_IDENT);
 				break;
 			case 'g':
+				flag &= ~(NV_SCOPES);
 				flag |= NV_GLOBAL;
+				scoping_flags++;
+				break;
+			case 'D':
+				flag &= ~(NV_SCOPES);
+				flag |= NV_DYNAMIC;
+				scoping_flags++;
+				break;
+			case 'P':
+				flag &= ~(NV_SCOPES);
+				flag |= NV_STATSCOPE;
+				scoping_flags++;
 				break;
 			case ':':
 				errormsg(SH_DICT,2, "%s", opt_info.arg);
@@ -444,6 +461,12 @@ int    b_typeset(int argc,char *argv[],Shbltin_t *context)
 endargs:
 	argv += opt_info.index;
 	opt_info.disc = 0;
+	/* 'local' builtin */
+	if(local && !sh.infunction)
+	{
+		errormsg(SH_DICT,ERROR_exit(1), "can only be used in a function");
+		UNREACHABLE();
+	}
 	/* handle argument of + and - specially */
 	if(*argv && argv[0][1]==0 && (*argv[0]=='+' || *argv[0]=='-'))
 		tdata.aflag = *argv[0];
@@ -466,9 +489,9 @@ int    b_typeset(int argc,char *argv[],Shbltin_t *context)
 		errormsg(SH_DICT,2,e_optincompat1,"-m");
 		error_info.errors++;
 	}
-	if((flag&NV_REF) && (flag&~(NV_REF|NV_IDENT|NV_ASSIGN|NV_GLOBAL)))
+	if((flag&NV_REF) && (flag&~(NV_REF|NV_IDENT|NV_ASSIGN|NV_SCOPES)))
 	{
-		errormsg(SH_DICT,2,e_optincompat2,"-n","other options except -g");
+		errormsg(SH_DICT,2,e_optincompat2,"-n","other options except -P, -D and -g");
 		error_info.errors++;
 	}
 	if((flag&NV_TYPE) && (flag&~(NV_TYPE|NV_VARNAME|NV_ASSIGN)))
@@ -497,11 +520,23 @@ int    b_typeset(int argc,char *argv[],Shbltin_t *context)
 		errormsg(SH_DICT,ERROR_exit(2),"option argument cannot be greater than %d",SHRT_MAX);
 		UNREACHABLE();
 	}
-	if((flag&NV_GLOBAL) && sh.mktype)
+	if((flag&NV_SCOPES) && sh.mktype)
 	{
-		errormsg(SH_DICT,ERROR_exit(2),"-g: type members cannot be global");
+		errormsg(SH_DICT,ERROR_exit(2),"type members cannot use the scoping flags -P, -D and -g");
 		UNREACHABLE();
 	}
+	if(scoping_flags > 1)
+	{
+		errormsg(SH_DICT,ERROR_exit(2),"the scoping flags -P, -D and -g cannot be combined");
+		UNREACHABLE();
+	}
+	if(troot==sh.var_tree && !sh.mktype && sh.infunction && !(flag&(NV_SCOPES)))
+	{
+		if(local || declare)
+			flag |= NV_DYNAMIC;
+		else if(sh.infunction==FUN_POSIX)
+			flag |= NV_GLOBAL;
+	}
 	if(isfloat)
 		flag |= NV_DOUBLE;
 	if(sflag)
@@ -511,7 +546,7 @@ int    b_typeset(int argc,char *argv[],Shbltin_t *context)
 		else if(!sh.typeinit)
 			flag |= NV_STATIC|NV_IDENT;
 	}
-	if(sh.fn_depth && !tdata.pflag)
+	if(sh.infunction < FUN_KSHDOT && !tdata.pflag)
 		flag |= NV_NOSCOPE;
 	if(tdata.help)
 		tdata.help = sh_strdup(tdata.help);
@@ -645,7 +680,7 @@ static int     setall(char **argv,int flag,Dt_t *troot,struct tdata *tp)
 {
 	char *name;
 	char *last = 0;
-	int nvflags=(flag&(NV_ARRAY|NV_NOARRAY|NV_VARNAME|NV_IDENT|NV_ASSIGN|NV_STATIC|NV_MOVE));
+	int nvflags=(flag&(NV_ARRAY|NV_NOARRAY|NV_VARNAME|NV_IDENT|NV_ASSIGN|NV_STATIC|NV_MOVE|NV_DYNAMIC));
 	int r=0, ref=0, comvar=(flag&NV_COMVAR),iarray=(flag&NV_IARRAY);
 	Dt_t *save_vartree = NULL;
 	Namval_t *save_namespace = NULL;

src/cmd/ksh93/data/builtins.c

@@ -70,6 +70,8 @@ const struct shtable3 shtab_builtins[] =
 	"functions",	NV_BLTIN|BLT_ENV,		bltin(typeset),
 	"integer",	NV_BLTIN|BLT_ENV|BLT_DCL,	bltin(typeset),
 	"nameref",	NV_BLTIN|BLT_ENV|BLT_DCL,	bltin(typeset),
+	"local",	NV_BLTIN|BLT_ENV|BLT_DCL,	bltin(typeset),
+	"declare",	NV_BLTIN|BLT_ENV|BLT_DCL,	bltin(typeset),
 	"test",		NV_BLTIN|BLT_ENV,		bltin(test),
 	"[",		NV_BLTIN|BLT_ENV,		bltin(test),
 	"let",		NV_BLTIN|BLT_ENV,		bltin(let),
@@ -729,7 +731,7 @@ const char sh_optexport[] =
         "[+>0?An error occurred.]"
 "}"
 
-"[+SEE ALSO?\bsh\b(1), \btypeset\b(1)]"
+"[+SEE ALSO?\bsh\b(1), \btypeset\b(1), \blocal\b(1)]"
 ;
 
 const char sh_optgetopts[] =
@@ -1541,7 +1543,7 @@ const char sh_optreadonly[] =
         "[+>0?An error occurred.]"
 "}"
 
-"[+SEE ALSO?\bsh\b(1), \btypeset\b(1)]"
+"[+SEE ALSO?\bsh\b(1), \btypeset\b(1), \blocal\b(1)]"
 ;
 
 const char sh_optredirect[] =
@@ -1691,6 +1693,7 @@ const char sh_optksh[] =
 
 "[+SEE ALSO?\bset\b(1), \bbuiltin\b(1)]"
 ;
+
 const char sh_optset[] =
 "+[-1c?\n@(#)$Id: set (ksh 93u+m) 2023-05-18 $\n]"
 "[--catalog?" SH_DICT "]"
@@ -1727,11 +1730,9 @@ const char sh_optset[] =
         "[+>0?An error occurred.]"
 "}"
 
-"[+SEE ALSO?\btypeset\b(1), \bshift\b(1)]"
+"[+SEE ALSO?\btypeset\b(1), \blocal\b(1), \bshift\b(1)]"
 ;
 
-
-
 const char sh_optshift[] =
 "[-1c?\n@(#)$Id: shift (AT&T Research) 1999-07-07 $\n]"
 "[--catalog?" SH_DICT "]"
@@ -1856,7 +1857,11 @@ const char sh_opttypeset[] =
 "[+?When \btypeset\b is called inside a function defined with the "
 	"\bfunction\b reserved word, and \aname\a does not contain a "
 	"\b.\b, then a local variable statically scoped to that function "
-	"will be created.]"
+	"will be created. If \btypeset\b is used in a POSIX function, a "
+	"variable is created in the global scope.]"
+"[+?\btypeset\b can also be invoked as \bdeclare\b, or (in functions "
+	"only) as \blocal\b. A variable created or modified by either \bdeclare\b "
+	"or \blocal\b is given a dynamic scope.]"
 "[+?Not all option combinations are possible. For example, the numeric "
 	"options \b-i\b, \b-E\b, and \b-F\b cannot be specified with "
 	"the justification options \b-L\b, \b-R\b, and \b-Z\b.]"
@@ -1912,7 +1917,10 @@ const char sh_opttypeset[] =
 "[n?Name reference. The value is the name of a variable that \aname\a "
 	"references. \aname\a cannot contain a \b.\b.]"
 "[p?Causes the output to be in a format that can be used as input to the "
-	"shell to recreate the attributes for variables.]"
+	"shell to recreate the attributes for variables. If this flag "
+	"is used by \btypeset\b in a POSIX function without also passing "
+	"\b-D\b or \b-P\b, the local scope is ignored and \btypeset\b will "
+	"only use the global scope.]"
 "[r?Enables readonly. Once enabled it cannot be disabled. See "
 	"\breadonly\b(1).]"
 "[s?Used with \b-i\b to restrict integer size to short.]"
@@ -1962,6 +1970,8 @@ const char sh_opttypeset[] =
 	"unset prior to processing the assignment list.]"
 "[T]:?[tname?\atname\a is the name of a type name given to each \aname\a.]"
 "[Z]#?[n?Zero fill. If \an\a is given it represents the field width.]"
+"[D?Modifies variables using a dynamic local scope in functions.]"
+"[P?Modifies variables using a static local scope in functions.]"
 "\n"
 "\n[name[=value]...]\n"
 " -f [-tu] [name...]\n"
@@ -2075,7 +2085,7 @@ const char sh_optunset[] =
 	"or an error occurred.]"
 "}"
 
-"[+SEE ALSO?\btypeset\b(1)]"
+"[+SEE ALSO?\btypeset\b(1), \blocal\b(1)]"
 ;
 
 const char sh_optunalias[] =