[COMMITTED] pkl: allow re-definition of variables, functions and units

[Jose E. Marchesi]

In order to ease interactive usage of poke, this patch makes it
possible to re-define variables, functions and units at the toplevel.

So this is now allowed:

(poke) var foo = 10;
(poke) var foo = 20;

But this of course is not:

fun f = void:
{
  var foo = 10;
  var foo = 20;
  ...
}

2020-11-18  Jose E. Marchesi  <jemarch@gnu.org>

        * libpoke/pkl-env.c (pkl_env_register): Adjust call to
        register_decl accordingly.
        (register_decl): Allow "redefining" variables, functions and
        types.
        * testsuite/poke.pkl/redef-1.pk: New test.
        * testsuite/poke.pkl/redef-2.pk: Likewise.
        * testsuite/poke.pkl/redef-3.pk: Likewise.
        * testsuite/poke.pkl/redef-diag-1.pk: Likewise.
        * testsuite/poke.pkl/redef-diag-2.pk: Likewise.
        * testsuite/poke.pkl/redef-diag-3.pk: Likewise.
        * testsuite/Makefile.am (EXTRA_DIST): Add new tests.
        * etc/poke.rec (Allow re-definitions of variables and units at the
        top-level): Remove as done.
---
 ChangeLog                          | 16 +++++++++++++++
 etc/poke.rec                       |  9 --------
 libpoke/pkl-env.c                  | 33 +++++++++++++++++++++++++-----
 testsuite/Makefile.am              |  6 ++++++
 testsuite/poke.pkl/redef-1.pk      | 11 ++++++++++
 testsuite/poke.pkl/redef-2.pk      | 14 +++++++++++++
 testsuite/poke.pkl/redef-3.pk      |  9 ++++++++
 testsuite/poke.pkl/redef-diag-1.pk |  8 ++++++++
 testsuite/poke.pkl/redef-diag-2.pk |  8 ++++++++
 testsuite/poke.pkl/redef-diag-3.pk |  8 ++++++++
 10 files changed, 108 insertions(+), 14 deletions(-)
 create mode 100644 testsuite/poke.pkl/redef-1.pk
 create mode 100644 testsuite/poke.pkl/redef-2.pk
 create mode 100644 testsuite/poke.pkl/redef-3.pk
 create mode 100644 testsuite/poke.pkl/redef-diag-1.pk
 create mode 100644 testsuite/poke.pkl/redef-diag-2.pk
 create mode 100644 testsuite/poke.pkl/redef-diag-3.pk

diff --git a/ChangeLog b/ChangeLog
index 6dcfbd59..29b83483 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2020-11-18  Jose E. Marchesi  <jemarch@gnu.org>
+
+       * libpoke/pkl-env.c (pkl_env_register): Adjust call to
+       register_decl accordingly.
+       (register_decl): Allow "redefining" variables, functions and
+       types.
+       * testsuite/poke.pkl/redef-1.pk: New test.
+       * testsuite/poke.pkl/redef-2.pk: Likewise.
+       * testsuite/poke.pkl/redef-3.pk: Likewise.
+       * testsuite/poke.pkl/redef-diag-1.pk: Likewise.
+       * testsuite/poke.pkl/redef-diag-2.pk: Likewise.
+       * testsuite/poke.pkl/redef-diag-3.pk: Likewise.
+       * testsuite/Makefile.am (EXTRA_DIST): Add new tests.
+       * etc/poke.rec (Allow re-definitions of variables and units at the
+       top-level): Remove as done.
+
 2020-11-18  Jose E. Marchesi  <jemarch@gnu.org>
 
        * etc/poke.rec (Allow re-definitions of variables and units at the
diff --git a/etc/poke.rec b/etc/poke.rec
index 5212de4a..ec2558d4 100644
--- a/etc/poke.rec
+++ b/etc/poke.rec
@@ -2252,15 +2252,6 @@ Description:
 + Support for mapping functions is a requirement for this.
 Requires: Support mapping and constructing functions
 
-Summary: Allow re-definitions of variables and units at the top-level
-Component: Compiler
-Kind: ENH
-Priority: 3
-Description:
-+ Re-defining variable and units at the top-level will ease interactive
-+ usage of poke by a lot.
-Target: 1.0
-
 Summary: Factorize promotion of expressions in promo
 Component: Compiler
 Kind: ENH
diff --git a/libpoke/pkl-env.c b/libpoke/pkl-env.c
index d8a3a8c6..00486b4b 100644
--- a/libpoke/pkl-env.c
+++ b/libpoke/pkl-env.c
@@ -118,15 +118,38 @@ get_registered (pkl_hash hash_table, const char *name)
 }
 
 static int
-register_decl (pkl_hash hash_table,
+register_decl (int top_level_p,
+               pkl_hash hash_table,
                const char *name,
                pkl_ast_node decl)
 {
   int hash;
+  pkl_ast_node found_decl;
 
-  if (get_registered (hash_table, name) != NULL)
-    /* Already registered.  */
-    return 0;
+  /* Check if DECL is already registered in the given hash table.
+
+     If we are in the global environment and the declaration is for a
+     variable, funcion, or an unit, then we allow "redefining" by
+     changing the name of the previous declaration to "".
+
+     Otherwise we don't register DECL, as it is already defined.  */
+
+  found_decl = get_registered (hash_table, name);
+  if (found_decl != NULL)
+    {
+      int decl_kind = PKL_AST_DECL_KIND (decl);
+
+      if (top_level_p
+          && (decl_kind == PKL_AST_DECL_KIND_VAR
+              || decl_kind == PKL_AST_DECL_KIND_FUNC
+              || decl_kind == PKL_AST_DECL_KIND_UNIT))
+        {
+          pkl_ast_node_free (PKL_AST_DECL_NAME (found_decl));
+          PKL_AST_DECL_NAME (found_decl) = NULL;
+        }
+      else
+        return 0;
+    }
 
   /* Add the declaration to the hash table.  */
   hash = hash_string (name);
@@ -206,7 +229,7 @@ pkl_env_register (pkl_env env,
 {
   pkl_hash *table = get_ns_table (env, namespace);
 
-  if (register_decl (*table, name, decl))
+  if (register_decl (env->up == NULL, *table, name, decl))
     {
       switch (PKL_AST_DECL_KIND (decl))
         {
diff --git a/testsuite/Makefile.am b/testsuite/Makefile.am
index c4fbb11a..f2c1d065 100644
--- a/testsuite/Makefile.am
+++ b/testsuite/Makefile.am
@@ -1285,6 +1285,12 @@ EXTRA_DIST = \
   poke.pkl/raise-6.pk \
   poke.pkl/raise-diag-1.pk \
   poke.pkl/rand-1.pk \
+  poke.pkl/redef-diag-1.pk \
+  poke.pkl/redef-diag-2.pk \
+  poke.pkl/redef-diag-3.pk \
+  poke.pkl/redef-1.pk \
+  poke.pkl/redef-2.pk \
+  poke.pkl/redef-3.pk \
   poke.pkl/return-1.pk \
   poke.pkl/return-2.pk \
   poke.pkl/return-diag-1.pk \
diff --git a/testsuite/poke.pkl/redef-1.pk b/testsuite/poke.pkl/redef-1.pk
new file mode 100644
index 00000000..2240ff70
--- /dev/null
+++ b/testsuite/poke.pkl/redef-1.pk
@@ -0,0 +1,11 @@
+/* { dg-do run } */
+
+var N = 2;
+fun f = int: { return N + 1; }
+
+/* { dg-command { var N = 10; } } */
+/* { dg-command { f } } */
+/* { dg-output "3" } */
+/* { dg-command { N + 1 } } */
+/* { dg-output "\n11" } */
+               
diff --git a/testsuite/poke.pkl/redef-2.pk b/testsuite/poke.pkl/redef-2.pk
new file mode 100644
index 00000000..42545b29
--- /dev/null
+++ b/testsuite/poke.pkl/redef-2.pk
@@ -0,0 +1,14 @@
+/* { dg-do run } */
+
+var N = 2;
+fun f = int: { return N + 1; }
+
+/* { dg-command { var oldf = f } } */
+/* { dg-command { fun f = int: { return 60 + N; } } } */
+/* { dg-command { f } } */
+/* { dg-output "62" } */
+/* { dg-command {fun f = int: { return 666; } } } */
+/* { dg-command {f} } */
+/* { dg-output "\n666" } */
+/* { dg-command { oldf } } */
+/* { dg-output "\n3" } */
diff --git a/testsuite/poke.pkl/redef-3.pk b/testsuite/poke.pkl/redef-3.pk
new file mode 100644
index 00000000..11c31489
--- /dev/null
+++ b/testsuite/poke.pkl/redef-3.pk
@@ -0,0 +1,9 @@
+/* { dg-do run } */
+
+unit Foo = 5;
+
+/* { dg-command { 2#Foo } } */
+/* { dg-output "2#5" } */
+/* { dg-command {unit Foo = 666} } */
+/* { dg-command {3#Foo} } */
+/* { dg-output "\n3#666" } */
diff --git a/testsuite/poke.pkl/redef-diag-1.pk 
b/testsuite/poke.pkl/redef-diag-1.pk
new file mode 100644
index 00000000..3e484e78
--- /dev/null
+++ b/testsuite/poke.pkl/redef-diag-1.pk
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+
+fun foo = void:
+{
+  var a = 10;
+  var b = 20;
+  var a = 30; /* { dg-error "" } */
+}
diff --git a/testsuite/poke.pkl/redef-diag-2.pk 
b/testsuite/poke.pkl/redef-diag-2.pk
new file mode 100644
index 00000000..aef2fe2f
--- /dev/null
+++ b/testsuite/poke.pkl/redef-diag-2.pk
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+
+fun foo = void:
+{
+  unit a = 10;
+  unit b = 20;
+  unit a = 30; /* { dg-error "" } */
+}
diff --git a/testsuite/poke.pkl/redef-diag-3.pk 
b/testsuite/poke.pkl/redef-diag-3.pk
new file mode 100644
index 00000000..60590a3f
--- /dev/null
+++ b/testsuite/poke.pkl/redef-diag-3.pk
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+
+fun foo = void:
+{
+  fun a = void: {}
+  fun b = void: {}
+  fun a = void: {} ; /* { dg-error "" } */
+}
-- 
2.25.0.2.g232378479e