oceani: add comments to var_block_close() and remove dead code.

[ocean] / csrc / oceani.mdc

diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index af24d9becd86326c48633e66cd0718a5510479da..7e1f2ac788117dddae2f9e2529e3d34ec8389aac 100644 (file)
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -953,13 +953,13 @@ Each variable records a scope depth and is in one of four states:
   enclosed the declaration, and that has closed.
 
 - "conditionally in scope".  The "in scope" block and all parallel
-  scopes have closed, and no further mention of the name has been
-  seen.  This state includes a secondary nest depth which records the
-  outermost scope seen since the variable became conditionally in
-  scope.  If a use of the name is found, the variable becomes "in
-  scope" and that secondary depth becomes the recorded scope depth.
-  If the name is declared as a new variable, the old variable becomes
-  "out of scope" and the recorded scope depth stays unchanged.
+  scopes have closed, and no further mention of the name has been seen.
+  This state includes a secondary nest depth (`min_depth`) which records
+  the outermost scope seen since the variable became conditionally in
+  scope.  If a use of the name is found, the variable becomes "in scope"
+  and that secondary depth becomes the recorded scope depth.  If the
+  name is declared as a new variable, the old variable becomes "out of
+  scope" and the recorded scope depth stays unchanged.
 
 - "out of scope".  The variable is neither in scope nor conditionally
   in scope.  It is permanently out of scope now and can be removed from
@@ -1141,7 +1141,14 @@ all pending-scope variables become conditionally scoped.
 
        static void var_block_close(struct parse_context *c, enum closetype ct)
        {
-               /* Close off all variables that are in_scope */
+               /* Close off all variables that are in_scope.
+                * Some variables in c->scope may already be not-in-scope,
+                * such as when a PendingScope variable is hidden by a new
+                * variable with the same name.
+                * So we check for v->name->var != v and drop them.
+                * If we choose to make a variable OutScope, we drop it
+                * immediately too.
+                */
                struct variable *v, **vp, *v2;
 
                scope_pop(c);
@@ -1150,12 +1157,12 @@ all pending-scope variables become conditionally scoped.
                     (v->scope == OutScope || v->name->var != v)
                     ? (*vp =  v->in_scope, 0)
                     : ( vp = &v->in_scope, 0)) {
-                       if (v->name->var != v) {
+                       v->min_depth = c->scope_depth;
+                       if (v->name->var != v)
                                /* This is still in scope, but we haven't just
                                 * closed the scope.
                                 */
                                continue;
-                       }
                        switch (ct) {
                        case CloseElse:
                        case CloseParallel: /* handle PendingScope */
@@ -1163,14 +1170,15 @@ all pending-scope variables become conditionally scoped.
                                case InScope:
                                case CondScope:
                                        if (c->scope_stack->child_count == 1)
+                                               /* first among parallel branches */
                                                v->scope = PendingScope;
                                        else if (v->previous &&
                                                 v->previous->scope == PendingScope)
+                                               /* all previous branches used name */
                                                v->scope = PendingScope;
                                        else if (v->type == Tlabel)     // UNTESTED
+                                               /* Labels remain pending even when not used */
                                                v->scope = PendingScope;        // UNTESTED
-                                       else if (v->name->var == v)     // UNTESTED
-                                               v->scope = OutScope;    // UNTESTED
                                        if (ct == CloseElse) {
                                                /* All Pending variables with this name
                                                 * are now Conditional */
@@ -1181,13 +1189,16 @@ all pending-scope variables become conditionally scoped.
                                        }
                                        break;
                                case PendingScope:
-                                       for (v2 = v;
-                                            v2 && v2->scope == PendingScope;
-                                            v2 = v2->previous)
-                                               if (v2->type != Tlabel)
-                                                       v2->scope = OutScope;
-                                       break;
-                               case OutScope: break;   // UNTESTED
+                                       /* Not possible as it would require
+                                        * parallel scope to be nested immediately
+                                        * in a parallel scope, and that never
+                                        * happens.
+                                        */
+                               case OutScope:
+                                       /* Not possible as we already tested for
+                                        * OutScope
+                                        */
+                                       abort();                // NOTEST
                                }
                                break;
                        case CloseSequential:
@@ -1208,7 +1219,6 @@ all pending-scope variables become conditionally scoped.
                                             v2 = v2->previous)
                                                if (v2->type == Tlabel) {
                                                        v2->scope = CondScope;
-                                                       v2->min_depth = c->scope_depth;
                                                } else
                                                        v2->scope = OutScope;
                                        break;