From: ceriel <none@none>
Date: Thu, 3 Apr 1986 00:44:39 +0000 (+0000)
Subject: Newer version, safety commit
X-Git-Tag: release-5-5~5325
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=52d743f22396a5d3f055bd9df2ee4160d218554f;p=ack.git

Newer version, safety commit
---

diff --git a/lang/m2/comp/Makefile b/lang/m2/comp/Makefile
index ef03535ec..b88cbb48a 100644
--- a/lang/m2/comp/Makefile
+++ b/lang/m2/comp/Makefile
@@ -14,7 +14,7 @@ LFLAGS =	-p
 LOBJ =	tokenfile.o program.o declar.o expression.o statement.o
 COBJ =	LLlex.o LLmessage.o char.o error.o main.o \
 	symbol2str.o tokenname.o idf.o input.o type.o def.o \
-	scope.o misc.o print.o enter.o
+	scope.o misc.o print.o enter.o defmodule.o
 OBJ =	$(COBJ) $(LOBJ) Lpars.o
 GENFILES=	tokenfile.c \
 	program.c declar.c expression.c statement.c \
@@ -69,18 +69,19 @@ LLlex.o: LLlex.h Lpars.h class.h f_info.h idf.h input.h
 LLmessage.o: LLlex.h Lpars.h idf.h
 char.o: class.h
 error.o: LLlex.h f_info.h input.h
-main.o: LLlex.h Lpars.h debug.h def.h f_info.h idf.h input.h main.h standards.h type.h
+main.o: LLlex.h Lpars.h debug.h def.h f_info.h idf.h input.h main.h scope.h standards.h type.h
 symbol2str.o: Lpars.h
 tokenname.o: Lpars.h idf.h tokenname.h
 idf.o: idf.h
 input.o: f_info.h input.h
 type.o: Lpars.h def.h def_sizes.h idf.h misc.h type.h
-def.o: Lpars.h debug.h def.h idf.h main.h misc.h scope.h
+def.o: Lpars.h debug.h def.h idf.h main.h misc.h scope.h type.h
 scope.o: LLlex.h debug.h def.h idf.h scope.h type.h
 misc.o: LLlex.h f_info.h idf.h misc.h
 enter.o: def.h idf.h misc.h scope.h type.h
+defmodule.o: LLlex.h def.h f_info.h idf.h input.h scope.h
 tokenfile.o: Lpars.h
-program.o: LLlex.h Lpars.h def.h idf.h main.h misc.h scope.h type.h
+program.o: LLlex.h Lpars.h debug.h def.h idf.h main.h misc.h scope.h type.h
 declar.o: LLlex.h Lpars.h def.h idf.h misc.h scope.h type.h
 expression.o: LLlex.h Lpars.h def.h idf.h scope.h
 statement.o: Lpars.h
diff --git a/lang/m2/comp/declar.g b/lang/m2/comp/declar.g
index 48a715dfb..b773b6cce 100644
--- a/lang/m2/comp/declar.g
+++ b/lang/m2/comp/declar.g
@@ -37,7 +37,7 @@ ProcedureHeading(struct def **pdf; int type;)
 				open_scope(OPENSCOPE, 0);
 			  }
 			}
-	FormalParameters(type, &params, &tp)?
+	FormalParameters(type == D_PROCEDURE, &params, &tp)?
 			{
 			  (*pdf)->df_type = tp = construct_type(PROCEDURE, tp);
 			  tp->prc_params = params;
@@ -133,8 +133,14 @@ TypeDeclaration
 			{ df->df_type = tp;
 			  if ((df->df_flags&D_EXPORTED) &&
 			      tp->tp_fund == ENUMERATION) {
-				exprt_literals(tp->enm_enums, enclosing(currscope));
+				exprt_literals(tp->enm_enums,
+						enclosing(CurrentScope));
 			  }
+			  if (df->df_kind == D_HTYPE &&
+			      tp->tp_fund != POINTER) {
+error("Opaque type \"%s\" is not a pointer type", df->df_idf->id_text);
+			  }
+				
 			}
 ;
 
@@ -246,27 +252,29 @@ ArrayType(struct type **ptp;)
 
 RecordType(struct type **ptp;)
 {
-	int scopenr;
+	struct scope scope;
 }
 :
 	RECORD
-			{ scopenr = uniq_scope(); }
-	FieldListSequence(scopenr)
+			{ scope.sc_scope = uniq_scope();
+			  scope.next = CurrentScope;
+			}
+	FieldListSequence(&scope)
 			{
 			  *ptp = standard_type(RECORD, record_align, (arith) 0 /* ???? */);
-			  (*ptp)->rec_scopenr = scopenr;
+			  (*ptp)->rec_scope = scope.sc_scope;
 			}
 	END
 ;
 
-FieldListSequence(int scopenr;):
-	FieldList(scopenr)
+FieldListSequence(struct scope *scope;):
+	FieldList(scope)
 	[
-		';' FieldList(scopenr)
+		';' FieldList(scope)
 	]*
 ;
 
-FieldList(int scopenr;)
+FieldList(struct scope *scope;)
 {
 	struct id_list *FldList;
 	struct idf *id;
@@ -283,21 +291,21 @@ FieldList(int scopenr;)
 				{ id = gen_anon_idf(); }
 	]			/* Changed rule in new modula-2 */
 	':' qualident(D_TYPE|D_HTYPE, &df, "type")
-				{ df1 = define(id, scopenr, D_FIELD);
+				{ df1 = define(id, scope, D_FIELD);
 				  df1->df_type = df->df_type;
 				}
-	OF variant(scopenr)
+	OF variant(scope)
 	[
-		'|' variant(scopenr)
+		'|' variant(scope)
 	]*
-	[ ELSE FieldListSequence(scopenr)
+	[ ELSE FieldListSequence(scope)
 	]?
 	END
 ]?
 ;
 
-variant(int scopenr;):
-	[ CaseLabelList ':' FieldListSequence(scopenr) ]?
+variant(struct scope *scope;):
+	[ CaseLabelList ':' FieldListSequence(scope) ]?
 					/* Changed rule in new modula-2 */
 ;
 
@@ -330,7 +338,7 @@ PointerType(struct type **ptp;)
 	struct def *lookfor();
 } :
 	POINTER TO
-	[ %if ( (df = lookup(dot.TOK_IDF, CurrentScope)))
+	[ %if ( (df = lookup(dot.TOK_IDF, CurrentScope->sc_scope)))
 		/* Either a Module or a Type, but in both cases defined
 		   in this scope, so this is the correct identification
 		*/
@@ -343,7 +351,8 @@ PointerType(struct type **ptp;)
 				  }
 				  else	tp = df->df_type;
 				}
-	| %if (df = lookfor(dot.TOK_IDF, currscope, 0), df->df_kind == D_MODULE)
+	| %if (df = lookfor(dot.TOK_IDF, CurrentScope, 0),
+	       df->df_kind == D_MODULE)
 		type(&tp)
 	|
 		IDENT
diff --git a/lang/m2/comp/def.c b/lang/m2/comp/def.c
index df198a824..9a51998fe 100644
--- a/lang/m2/comp/def.c
+++ b/lang/m2/comp/def.c
@@ -25,6 +25,7 @@ struct def *ill_df = &illegal_def;
 struct def *
 define(id, scope, kind)
 	register struct idf *id;
+	struct scope *scope;
 {
 	/*	Declare an identifier in a scope, but first check if it
 		already has been defined. If so, error message.
@@ -32,14 +33,14 @@ define(id, scope, kind)
 	register struct def *df;
 	register struct scope *sc;
 
-	DO_DEBUG(debug(4,"Defining identifier %s in scope %d", id->id_text, scope));
-	df = lookup(id, scope);
+	DO_DEBUG(debug(4,"Defining identifier %s in scope %d", id->id_text, scope->sc_scope));
+	df = lookup(id, scope->sc_scope);
 	if (	/* Already in this scope */
 		df
 	   ||	/* A closed scope, and id defined in the pervasive scope */
 		( CurrentScope == scope 
 		&&
-		  scopeclosed(currscope)
+		  scopeclosed(CurrentScope)
 		&&
 		  (df = lookup(id, 0)))
 	   ) {
@@ -68,19 +69,14 @@ define(id, scope, kind)
 	}
 	df = new_def();
 	df->df_idf = id;
-	df->df_scope = scope;
+	df->df_scope = scope->sc_scope;
 	df->df_kind = kind;
 	df->next = id->id_def;
 	id->id_def = df;
 
 	/* enter the definition in the list of definitions in this scope */
-	sc = currscope;
-	while (sc->sc_scope != scope) {
-		sc = sc->next;
-		assert(sc != 0);
-	}
-	df->df_nextinscope = sc->sc_def;
-	sc->sc_def = df;
+	df->df_nextinscope = scope->sc_def;
+	scope->sc_def = df;
 	return df;
 }
 
@@ -135,7 +131,7 @@ Export(ids, qualified)
 		}
 		else {
 			df->df_flags |= D_EXPORTED;
-			df = define(ids->id_ptr, enclosing(currscope)->sc_scope,
+			df = define(ids->id_ptr, enclosing(CurrentScope),
 					D_IMPORT);
 		}
 		ids = ids->next;
@@ -164,55 +160,56 @@ Import(ids, id, local)
 	int imp_kind;
 #define FROM_MODULE	0
 #define FROM_ENCLOSING	1
-	struct def *lookfor();
+	struct def *lookfor(), *GetDefinitionModule();
 
-	if (local) {
-		kind = D_IMPORT;
-		scope = enclosing(currscope)->sc_scope;
-		if (!id) imp_kind = FROM_ENCLOSING;
-		else {
-			imp_kind = FROM_MODULE;
-			df = lookfor(id, enclosing(currscope), 1);
-			if (df->df_kind != D_MODULE) {
-				/* enter all "ids" with type D_ERROR */
-				kind = D_ERROR;
-				if (df->df_kind != D_ERROR) {
+	kind = D_IMPORT;
+	scope = enclosing(CurrentScope)->sc_scope;
+	if (!id) imp_kind = FROM_ENCLOSING;
+	else {
+		imp_kind = FROM_MODULE;
+		if (local) df = lookfor(id, enclosing(CurrentScope), 1);
+		else df = GetDefinitionModule(id);
+		if (df->df_kind != D_MODULE) {
+			/* enter all "ids" with type D_ERROR */
+			kind = D_ERROR;
+			if (df->df_kind != D_ERROR) {
 error("identifier \"%s\" does not represent a module", id->id_text);
-				}
 			}
-			else	scope = df->mod_scope;
 		}
-		while (ids) {
-			if (imp_kind == FROM_MODULE) {
-				if (!(df = lookup(ids->id_ptr, scope))) {
+		else	scope = df->mod_scope;
+	}
+	while (ids) {
+		if (imp_kind == FROM_MODULE) {
+			if (!(df = lookup(ids->id_ptr, scope))) {
 error("identifier \"%s\" not declared in qualifying module",
 ids->id_ptr->id_text);
-					df = ill_df;
-				}
-				else 
-				if (!(df->df_flags&(D_EXPORTED|D_QEXPORTED))) {
+				df = ill_df;
+			}
+			else 
+			if (!(df->df_flags&(D_EXPORTED|D_QEXPORTED))) {
 error("identifier \"%s\" not exported from qualifying module",
 ids->id_ptr->id_text);
-				}
 			}
-			else {
-				df = lookfor(ids->id_ptr, enclosing(currscope), 0);
-				if (df->df_kind == D_ERROR) {
+		}
+		else {
+			if (local) {
+				df = lookfor(ids->id_ptr,
+					     enclosing(CurrentScope), 0);
+			} else df = GetDefinitionModule(ids->id_ptr);
+			if (df->df_kind == D_ERROR) {
 error("identifier \"%s\" not visible in enclosing scope",
 ids->id_ptr->id_text);
-				}
-			}
-			define(ids->id_ptr, CurrentScope, kind)->imp_def = df;
-			if (df->df_kind == D_TYPE &&
-			    df->df_type->tp_fund == ENUMERATION) {
-				/* Also import all enumeration literals */
-				exprt_literals(df->df_type->enm_enums, currscope);
 			}
-			ids = ids->next;
 		}
-		return;
+		define(ids->id_ptr, CurrentScope, kind)->imp_def = df;
+		if (df->df_kind == D_TYPE &&
+		    df->df_type->tp_fund == ENUMERATION) {
+			/* Also import all enumeration literals */
+			exprt_literals(df->df_type->enm_enums,
+					CurrentScope);
+		}
+		ids = ids->next;
 	}
-	/* ???? */
 }
 
 exprt_literals(df, toscope)
@@ -223,7 +220,7 @@ exprt_literals(df, toscope)
 		as an import from the scope "toscope".
 	*/
 	while (df) {
-		define(df->df_idf, toscope->sc_scope, D_IMPORT)->imp_def = df;
+		define(df->df_idf, toscope, D_IMPORT)->imp_def = df;
 		df = df->enm_next;
 	}
 }
diff --git a/lang/m2/comp/defmodule.c b/lang/m2/comp/defmodule.c
new file mode 100644
index 000000000..b007705dc
--- /dev/null
+++ b/lang/m2/comp/defmodule.c
@@ -0,0 +1,66 @@
+/* D E F I N I T I O N   M O D U L E S */
+
+#include	<assert.h>
+#include	<em_arith.h>
+#include	<em_label.h>
+#include	"idf.h"
+#include	"input.h"
+#include	"scope.h"
+#include	"def.h"
+#include	"LLlex.h"
+#include	"f_info.h"
+
+GetFile(name)
+	char *name;
+{
+	/*	Try to find a file with basename "name" and extension ".def",
+		in the directories mentioned in "DEFPATH".
+	*/
+	extern char *DEFPATH[];
+	char buf[256];
+
+	(void) strcpy(buf, name);
+	if (strlen(buf) > 10) {
+		(void) strcpy(&buf[10], ".def");
+	}
+	else	(void) strcat(buf, ".def");
+	if (! InsertFile(buf, DEFPATH, &(FileName))) {
+		fatal("Could'nt find a DEFINITION MODULE for \"%s\"", name);
+	}
+	LineNumber = 1;
+}
+
+struct def *
+GetDefinitionModule(id)
+	struct idf *id;
+{
+	/*	Return a pointer to the "def" structure of the definition
+		module indicated by "id".
+		We may have to read the definition module itself.
+	*/
+	struct def *df;
+
+	df = lookup(id, GlobalScope->sc_scope);
+	if (!df) {
+		/* Read definition module. Make an exception for SYSTEM.
+		*/
+		if (!strcmp(id->id_text, "SYSTEM")) {
+			do_SYSTEM();
+		}
+		else {
+			GetFile(id->id_text);
+			DefModule();
+		}
+		df = lookup(id, GlobalScope->sc_scope);
+	}
+	assert(df != 0 && df->df_kind == D_MODULE);
+	return df;
+}
+
+AtEoIF()
+{
+	/*	Make the unstacking of input streams noticable by the
+	   	lexical analyzer
+	*/
+	return 1;
+}
diff --git a/lang/m2/comp/enter.c b/lang/m2/comp/enter.c
index 5c37e1eea..1912eabd0 100644
--- a/lang/m2/comp/enter.c
+++ b/lang/m2/comp/enter.c
@@ -11,9 +11,6 @@ static char *RcsId = "$Header$";
 #include	"scope.h"
 #include	"misc.h"
 
-extern struct idf *str2idf();
-extern struct def *define();
-
 struct def *
 Enter(name, kind, type, pnam)
 	char *name;
@@ -35,6 +32,7 @@ Enter(name, kind, type, pnam)
 EnterIdList(idlist, kind, flags, type, scope)
 	register struct id_list *idlist;
 	struct type *type;
+	struct scope *scope;
 {
 	register struct def *df;
 	struct def *first = 0, *last = 0;
@@ -78,6 +76,6 @@ lookfor(id, scope, give_error)
 		if (df) return df;
 		sc = nextvisible(sc);
 	}
-	if (give_error) error("Identifier \"%s\" not declared", id->id_text);
-	return define(id, scope->sc_scope, D_ERROR);
+	if (give_error) error("identifier \"%s\" not declared", id->id_text);
+	return define(id, scope, D_ERROR);
 }
diff --git a/lang/m2/comp/expression.g b/lang/m2/comp/expression.g
index c46119156..7f1c3ca38 100644
--- a/lang/m2/comp/expression.g
+++ b/lang/m2/comp/expression.g
@@ -26,7 +26,8 @@ qualident(int types; struct def **pdf; char *str;)
 	struct def *lookfor();
 } :
 	IDENT		{ if (types) {
-				*pdf = df = lookfor(dot.TOK_IDF, currscope, 1);
+				df = lookfor(dot.TOK_IDF, CurrentScope, 1);
+				*pdf = df;
 				if (df->df_kind == D_ERROR) types = 0;
 			  }
 			}
diff --git a/lang/m2/comp/input.h b/lang/m2/comp/input.h
index aa28ffc1a..550cdc501 100644
--- a/lang/m2/comp/input.h
+++ b/lang/m2/comp/input.h
@@ -5,5 +5,5 @@
 #define INP_NPUSHBACK 2
 #define INP_TYPE	struct f_info
 #define INP_VAR		file_info
-#define INP_READ_IN_ONE
+
 #include <inp_pkg.spec>
diff --git a/lang/m2/comp/main.c b/lang/m2/comp/main.c
index 2bd33a04b..8cccad745 100644
--- a/lang/m2/comp/main.c
+++ b/lang/m2/comp/main.c
@@ -14,12 +14,15 @@ static char *RcsId = "$Header$";
 #include	"debug.h"
 #include	"type.h"
 #include	"def.h"
+#include	"scope.h"
 #include	"standards.h"
 
 char options[128];
 char *ProgName;
 int state;
 extern int err_occurred;
+char *DEFPATH[128];
+char *getenv();
 
 main(argc, argv)
 	char *argv[];
@@ -53,12 +56,13 @@ Compile(src)
 	extern struct tokenname tkidf[];
 
 	DO_DEBUG(debug(1,"Filename : %s", src));
-	if (! InsertFile(src, (char **) 0)) {
+	if (! InsertFile(src, (char **) 0, &src)) {
 		fprintf(STDERR,"%s: cannot open %s\n", ProgName, src);
 		return 0;
 	}
 	LineNumber = 1;
 	FileName = src;
+	init_DEFPATH();
 	init_idf();
 	reserve(tkidf);
 	init_scope();
@@ -69,10 +73,13 @@ Compile(src)
 		LexScan();
 	else if (options['T'])
 		TimeScan();
-	else
+	else {
 #endif DEBUG
+		(void) open_scope(CLOSEDSCOPE, 0);
+		GlobalScope = CurrentScope;
 		CompUnit();
 #ifdef DEBUG
+	}
 	if (options['h']) hash_stat();
 #endif DEBUG
 	if (err_occurred) return 0;
@@ -169,3 +176,33 @@ add_standards()
 	df->df_value.df_enum.en_val = 1;
 	df->df_value.df_enum.en_next = 0;
 }
+
+init_DEFPATH()
+{
+	register char *p = getenv("M2path");
+	register int i = 0;
+
+	if (p) {
+		while (*p) {
+			DEFPATH[i++] = p;
+			while (*p && *p != ':') p++;
+			if (*p) *p++ = '\0';
+		}
+	}
+	DEFPATH[i] = 0;
+}
+
+do_SYSTEM()
+{
+	/*	Simulate the reading of the SYSTEM definition module
+	*/
+	struct def *df;
+	struct idf *sys_id;
+
+	sys_id = str2idf("SYSTEM", 0);
+	df = define(sys_id, GlobalScope, D_MODULE);
+	open_scope(CLOSEDSCOPE, 0);
+	df->mod_scope = CurrentScope->sc_scope;
+	/* ???? */
+	close_scope();
+}
diff --git a/lang/m2/comp/program.g b/lang/m2/comp/program.g
index c4c7b3d57..68c5be233 100644
--- a/lang/m2/comp/program.g
+++ b/lang/m2/comp/program.g
@@ -13,6 +13,7 @@ static  char *RcsId = "$Header$";
 #include	"scope.h"
 #include	"def.h"
 #include	"type.h"
+#include	"debug.h"
 }
 /*
 	The grammar as given by Wirth is already almost LL(1); the
@@ -31,6 +32,7 @@ static  char *RcsId = "$Header$";
 %lexical LLlex;
 
 %start	CompUnit, CompilationUnit;
+%start	DefModule, DefinitionModule;
 
 ModuleDeclaration
 {
@@ -41,11 +43,11 @@ ModuleDeclaration
 				  id = dot.TOK_IDF;
 				  df = define(id, CurrentScope, D_MODULE);
 				  open_scope(CLOSEDSCOPE, 0);
-				  df->mod_scope = CurrentScope;
+				  df->mod_scope = CurrentScope->sc_scope;
 				}
 	priority? ';'
 	import(1)*
-	export?
+	export(0)?
 	block
 	IDENT			{ close_scope();
 				  match_id(id, dot.TOK_IDF);
@@ -56,7 +58,7 @@ priority:
 	'[' ConstExpression ']'
 ;
 
-export
+export(int def;)
 {
 	struct id_list *ExportList;
 	int QUALflag = 0;
@@ -67,7 +69,8 @@ export
 	]?
 	IdentList(&ExportList) ';'
 			{
-			  Export(ExportList, QUALflag);
+			  if (!def) Export(ExportList, QUALflag);
+			  else warning("export list in definition module ignored");
 			  FreeIdList(ExportList);
 			}
 ;
@@ -95,23 +98,31 @@ import(int local;)
 
 DefinitionModule
 {
-	struct def *df;
+	register struct def *df;
 	struct idf *id;
 } :
 	DEFINITION	{ state = DEFINITION; }
 	MODULE IDENT	{ id = dot.TOK_IDF;
-			  df = define(id, CurrentScope, D_MODULE);
+			  df = define(id, GlobalScope, D_MODULE);
 			  open_scope(CLOSEDSCOPE, 0);
-			  df->mod_scope = CurrentScope;
+			  df->mod_scope = CurrentScope->sc_scope;
+			  DO_DEBUG(debug(1, "Definition module \"%s\"", id->id_text));
 			}
 	';'
 	import(0)* 
-	/*	export?
+	export(1)?
 
-	   	New Modula-2 does not have export lists in definition modules.
+	/*	New Modula-2 does not have export lists in definition modules.
 	*/
 	definition* END IDENT '.'
-			{ close_scope();
+			{
+			  df = CurrentScope->sc_def;
+			  while (df) {
+				/* Make all definitions "QUALIFIED EXPORT" */
+				df->df_flags |= D_QEXPORTED;
+				df = df->df_nextinscope;
+			  }
+			  close_scope();
 			  match_id(id, dot.TOK_IDF);
 			}
 ;
@@ -124,7 +135,7 @@ definition
 	CONST [ ConstantDeclaration ';' ]*
 |
 	TYPE
-	[ IDENT 
+	[ IDENT 	{ df = define(dot.TOK_IDF, CurrentScope, D_TYPE); }
 	  [ '=' type(&tp)
 	  | /* empty */
 	    /*
@@ -132,6 +143,7 @@ definition
 	       The export is said to be opaque.
 	       It is restricted to pointer types.
 	    */
+	    		{ df->df_kind = D_HIDDEN; }
 	  ]
 	  ';'
 	]*
@@ -141,19 +153,20 @@ definition
 	ProcedureHeading(&df, D_PROCHEAD) ';'
 ;
 
-ProgramModule {
+ProgramModule
+{
 	struct idf *id;
+	struct def *df, *GetDefinitionModule();
+	int scope = 0;
 } :
 	MODULE		{ if (state != IMPLEMENTATION) state = PROGRAM; }
-	IDENT		{ if (state == IMPLEMENTATION) {
-				/* ????
-				   Read definition module,
-				   Look for current identifier,
-				   and find out its scope number
-				*/
-			  }
+	IDENT		{ 
 			  id = dot.TOK_IDF;
-			  open_scope(CLOSEDSCOPE, 0);
+			  if (state == IMPLEMENTATION) {
+				   df = GetDefinitionModule(id);
+				   scope = df->mod_scope;
+			  }
+			  open_scope(CLOSEDSCOPE, scope);
 			}
 	priority?
 	';' import(0)*
diff --git a/lang/m2/comp/scope.C b/lang/m2/comp/scope.C
index ef2080d4a..1a2badcd5 100644
--- a/lang/m2/comp/scope.C
+++ b/lang/m2/comp/scope.C
@@ -15,41 +15,44 @@ static char *RcsId = "$Header$";
 
 static int maxscope;		/* maximum assigned scope number */
 
-struct scope *currscope;
+struct scope *CurrentScope, *GlobalScope;
 
 /* STATICALLOCDEF "scope" */
 
-/*	Open a scope that is either open (automatic imports) or closed.
-	A closed scope is handled by adding an extra entry to the list
-	with scope number 0. This has two purposes: it makes scope 0
-	visible, and it marks the end of a visibility list.
-	Scope 0 is the pervasive scope, the one that is always visible.
-	A disadvantage of this method is that we cannot open scope 0
-	explicitly.
-*/
-open_scope(scopetype, scopenr)
+open_scope(scopetype, scope)
 {
+	/*	Open a scope that is either open (automatic imports) or closed.
+		A closed scope is handled by adding an extra entry to the list
+		with scope number 0. This has two purposes: it makes scope 0
+		visible, and it marks the end of a visibility list.
+		Scope 0 is the pervasive scope, the one that is always visible.
+		A disadvantage of this method is that we cannot open scope 0
+		explicitly.
+	*/
 	register struct scope *sc = new_scope();
 	register struct scope *sc1;
 
-	sc->sc_scope = scopenr == 0 ? ++maxscope : scopenr;
+	sc->sc_scope = scope == 0 ? ++maxscope : scope;
+	sc->sc_forw = 0; sc->sc_def = 0;
 	assert(scopetype == OPENSCOPE || scopetype == CLOSEDSCOPE);
-	DO_DEBUG(debug(1, "Opening a %s scope", scopetype == OPENSCOPE ? "open" : "closed"));
-	sc1 = currscope;
+	DO_DEBUG(debug(1, "Opening a %s scope",
+			scopetype == OPENSCOPE ? "open" : "closed"));
+	sc1 = CurrentScope;
 	if (scopetype == CLOSEDSCOPE) {
 		sc1 = new_scope();
 		sc1->sc_scope = 0;		/* Pervasive scope nr */
-		sc1->next = currscope;
+		sc1->sc_forw = 0; sc1->sc_def = 0;
+		sc1->next = CurrentScope;
 	}
 	sc->next = sc1;
-	currscope = sc;
+	CurrentScope = sc;
 }
 
 static rem_forwards();
 
 close_scope()
 {
-	register struct scope *sc = currscope;
+	register struct scope *sc = CurrentScope;
 
 	assert(sc != 0);
 	DO_DEBUG(debug(1, "Closing a scope"));
@@ -60,7 +63,7 @@ close_scope()
 		sc = sc->next;
 		free_scope(sc1);
 	}
-	currscope = sc->next;
+	CurrentScope = sc->next;
 	free_scope(sc);
 }
 
@@ -69,8 +72,9 @@ init_scope()
 	register struct scope *sc = new_scope();
 
 	sc->sc_scope = 0;
-	sc->next = 0;
-	currscope = sc;
+	sc->sc_forw = 0;
+	sc->sc_def = 0;
+	CurrentScope = sc;
 }
 
 int
@@ -87,29 +91,29 @@ struct forwards {
 
 /* STATICALLOCDEF "forwards" */
 
-/*	Enter a forward reference into a list belonging to the
-	current scope. This is used for POINTER declarations, which
-	may have forward references that must howewer be declared in the
-	same scope.
-*/
 Forward(tk, ptp)
 	struct token *tk;
 	struct type **ptp;
 {
+	/*	Enter a forward reference into a list belonging to the
+		current scope. This is used for POINTER declarations, which
+		may have forward references that must howewer be declared in the
+		same scope.
+	*/
 	register struct forwards *f = new_forwards();
 
 	f->fo_tok = *tk;
 	f->fo_ptyp = ptp;
-	f->next = currscope->sc_forw;
-	currscope->sc_forw = f;
+	f->next = CurrentScope->sc_forw;
+	CurrentScope->sc_forw = f;
 }
 
-/*	When closing a scope, all forward references must be resolved
-*/
 static
 rem_forwards(fo)
 	struct forwards *fo;
 {
+	/*	When closing a scope, all forward references must be resolved
+	*/
 	register struct forwards *f;
 	struct token savetok;
 	register struct def *df;
@@ -118,9 +122,10 @@ rem_forwards(fo)
 	savetok = dot;
 	while (f = fo) {
 		dot = f->fo_tok;
-		df = lookfor(dot.TOK_IDF, currscope, 1);
+		df = lookfor(dot.TOK_IDF, CurrentScope, 1);
 		if (!(df->df_kind & (D_TYPE | D_HTYPE | D_ERROR))) {
-			error("identifier \"%s\" not a type", df->df_idf->id_text);
+			error("identifier \"%s\" not a type",
+			      df->df_idf->id_text);
 		}
 		*(f->fo_ptyp) = df->df_type;
 		fo = f->next;
diff --git a/lang/m2/comp/scope.h b/lang/m2/comp/scope.h
index 35253bec8..c8e6d9c92 100644
--- a/lang/m2/comp/scope.h
+++ b/lang/m2/comp/scope.h
@@ -16,9 +16,9 @@ struct scope {
 };
 
 extern struct scope
-	*currscope;
+	*CurrentScope,
+	*GlobalScope;
 
 #define nextvisible(x)	((x)->sc_scope ? (x)->next : (struct scope *) 0)
 #define scopeclosed(x)	((x)->next->sc_scope == 0)
 #define enclosing(x)	(scopeclosed(x) ? (x)->next->next : (x)->next)
-#define CurrentScope	(currscope->sc_scope)
diff --git a/lang/m2/comp/type.H b/lang/m2/comp/type.H
index 0f2a2ee40..f2ebb8022 100644
--- a/lang/m2/comp/type.H
+++ b/lang/m2/comp/type.H
@@ -38,9 +38,9 @@ struct array {
 };
 
 struct record {
-	int rc_scopenr;		/* Scope number of this record */
+	int rc_scope;		/* Scope number of this record */
 				/* Members are in the symbol table */
-#define rec_scopenr	tp_value.tp_record.rc_scopenr
+#define rec_scope	tp_value.tp_record.rc_scope
 };
 
 struct proc {
diff --git a/lang/m2/comp/type.c b/lang/m2/comp/type.c
index ae9aa6fb6..3d5fe9090 100644
--- a/lang/m2/comp/type.c
+++ b/lang/m2/comp/type.c
@@ -144,7 +144,7 @@ has_selectors(df)
 		register struct type *tp = df->df_type;
 
 		if (tp->tp_fund == RECORD) {
-			return tp->rec_scopenr;
+			return tp->rec_scope;
 		}
 		break;
 		}