Now detects use before declaration, f.i. in

VAR k: REAL;
REAL : INTEGER;

diff --git a/lang/m2/comp/Version.c b/lang/m2/comp/Version.c
index ff5e11d..1fa3d2a 100644 (file)
--- a/lang/m2/comp/Version.c
+++ b/lang/m2/comp/Version.c
@@ -1 +1 @@
-static char Version[] = "ACK Modula-2 compiler Version 0.24";
+static char Version[] = "ACK Modula-2 compiler Version 0.25";

diff --git a/lang/m2/comp/def.H b/lang/m2/comp/def.H
index abe0901..b9c4903 100644 (file)
--- a/lang/m2/comp/def.H
+++ b/lang/m2/comp/def.H
@@ -98,9 +98,11 @@ struct def   {               /* list of definitions for a name */
 #define D_ERROR                0x4000  /* a compiler generated definition for an
                                   undefined variable
                                */
+#define D_INUSE                0x8000  /* identification in this scope (like D_IMPORT)
+                               */
 #define D_VALUE        (D_PROCEDURE|D_VARIABLE|D_FIELD|D_ENUM|D_CONST|D_PROCHEAD)
 #define D_ISTYPE       (D_HIDDEN|D_TYPE|D_FTYPE)
-#define D_IMPORTED     (D_IMPORT)
+#define D_IMPORTED     (D_IMPORT|D_INUSE)
 #define is_type(dfx)   ((dfx)->df_kind & D_ISTYPE)
        unsigned short  df_flags;
 #define D_NOREG                0x01    /* set if it may not reside in a register */

diff --git a/lang/m2/comp/def.c b/lang/m2/comp/def.c
index 613af6b..1c3e633 100644 (file)
--- a/lang/m2/comp/def.c
+++ b/lang/m2/comp/def.c
@@ -96,16 +96,22 @@ define(id, scope, kind)
        */
        register t_def *df;
 
-       df = lookup(id, scope, 1, 0);
+       df = lookup(id, scope, 2, 0);
        if (    /* Already in this scope */
                df
           ||   /* A closed scope, and id defined in the pervasive scope */
                ( 
                  scopeclosed(scope)
                &&
-                 (df = lookup(id, PervasiveScope, 1, 0)))
+                 (df = lookup(id, PervasiveScope, 2, 0)))
           ) {
                switch(df->df_kind) {
+               case D_INUSE:
+                       if (kind != D_INUSE) {
+                               error("identifier \"%s\" already used; may not be redefined in this scope", df->df_idf->id_text);
+                       }
+                       return df;
+
                case D_HIDDEN:
                        /* An opaque type. We may now have found the
                           definition of this type.

diff --git a/lang/m2/comp/lookup.c b/lang/m2/comp/lookup.c
index 6656ea1..8375aac 100644 (file)
--- a/lang/m2/comp/lookup.c
+++ b/lang/m2/comp/lookup.c
@@ -23,6 +23,8 @@
 #include       "type.h"
 #include       "misc.h"
 
+extern int     pass_1;
+
 t_def *
 lookup(id, scope, import, flags)
        register t_idf *id;
@@ -55,6 +57,7 @@ lookup(id, scope, import, flags)
                df->df_flags |= flags;
                if (import) {
                        while (df->df_kind & D_IMPORTED) {
+                               if (df->df_kind == D_INUSE && import != 1) break;
                                assert(df->imp_def != 0);
                                df = df->imp_def;
                        }
@@ -66,23 +69,31 @@ lookup(id, scope, import, flags)
 t_def *
 lookfor(id, vis, message, flags)
        register t_node *id;
-       t_scopelist *vis;
+       register t_scopelist *vis;
 {
        /*      Look for an identifier in the visibility range started by "vis".
                If it is not defined create a dummy definition and,
                if message is set, give an error message
        */
-       register t_def *df;
        register t_scopelist *sc = vis;
+       t_def *df;
 
        while (sc) {
                df = lookup(id->nd_IDF, sc->sc_scope, 1, flags);
-               if (df) return df;
+               if (df) {
+                       if (pass_1 &&
+                           message && 
+                           sc->sc_scope->sc_level < vis->sc_scope->sc_level &&
+                           ! scopeclosed(vis->sc_scope)) {
+                               define(id->nd_IDF, vis->sc_scope, D_INUSE)->
+                                       imp_def = df;
+                       }
+                       return df;
+               }
                sc = nextvisible(sc);
        }
 
        if (message) id_not_declared(id);
 
-       df = MkDef(id->nd_IDF, vis->sc_scope, D_ERROR);
-       return df;
+       return MkDef(id->nd_IDF, vis->sc_scope, D_ERROR);
 }

diff --git a/lang/m2/comp/scope.C b/lang/m2/comp/scope.C
index 70eb52d..4e92c40 100644 (file)
--- a/lang/m2/comp/scope.C
+++ b/lang/m2/comp/scope.C
@@ -188,7 +188,7 @@ Reverse(pdf)
                from this list.
        */
        register t_def *df, *df1;
-#define INTERESTING D_MODULE|D_PROCEDURE|D_PROCHEAD|D_VARIABLE
+#define INTERESTING (D_MODULE|D_PROCEDURE|D_PROCHEAD|D_VARIABLE|D_IMPORTED)
 
        df = 0;
        df1 = *pdf;

diff --git a/lang/m2/comp/walk.c b/lang/m2/comp/walk.c
index 49e8e3c..46b3c68 100644 (file)
--- a/lang/m2/comp/walk.c
+++ b/lang/m2/comp/walk.c
@@ -860,8 +860,8 @@ UseWarnings(df)
                        register t_def *df1 = df->imp_def;
 
                        df1->df_flags |= df->df_flags & (D_USED|D_DEFINED);
-                       if (df->df_kind == D_IMPORT &&
-                           !(df->df_flags & D_IMP_BY_EXP)) {
+                       if (df->df_kind == D_INUSE) return;
+                       if ( !(df->df_flags & D_IMP_BY_EXP)) {
                                if (! (df->df_flags & (D_USED | D_DEFINED))) {
                                        node_warning(
                                                df->df_scope->sc_end,