* libguile/eval.c (s_expression): Added comment.

(s_empty_combination, error_unbound_variable): New static
	identifiers.

	(SCM_VALIDATE_NON_EMPTY_COMBINATION, SCM_EVALIM2, scm_lookupcar1):
	Use ASSERT_SYNTAX, syntax_error or error_unbound_variable to
	signal syntax errors.

	(SCM_CEVAL): Separated handling of evaluator bytecodes and other
	scheme objects.

	* test-suite/tests/syntax.test (exception:missing/extra-expr-misc):
	Removed.

	(exception:illegal-empty-combination): New.

	(exception:missing/extra-expr): Unified capitalization.

	Adapted test for '()' to the new way of error reporting.

libguile/ChangeLog

@@ -1,3 +1,17 @@
+2003-11-01  Dirk Herrmann  <D.Herrmann@tu-bs.de>
+
+	* eval.c (s_expression): Added comment.
+
+	(s_empty_combination, error_unbound_variable): New static
+	identifiers.
+
+	(SCM_VALIDATE_NON_EMPTY_COMBINATION, SCM_EVALIM2, scm_lookupcar1):
+	Use ASSERT_SYNTAX, syntax_error or error_unbound_variable to
+	signal syntax errors.
+
+	(SCM_CEVAL): Separated handling of evaluator bytecodes and other
+	scheme objects.
+
 2003-10-25  Dirk Herrmann  <D.Herrmann@tu-bs.de>
 
 	* eval.c (unmemocar, sym_three_question_marks, scm_unmemocar):

libguile/eval.c

@@ -101,6 +101,11 @@ char *alloca ();
  * expression is expected, a 'Bad expression' error is signalled.  */
 static const char s_bad_expression[] = "Bad expression";
 
+/* If a form is detected that holds a different number of expressions than are
+ * required in that context, a 'Missing or extra expression' error is
+ * signalled.  */
+static const char s_expression[] = "Missing or extra expression in";
+
 /* If a form is detected that holds less expressions than are required in that
  * context, a 'Missing expression' error is signalled.  */
 static const char s_missing_expression[] = "Missing expression in";
@@ -109,6 +114,13 @@ static const char s_missing_expression[] = "Missing expression in";
  * context, an 'Extra expression' error is signalled.  */
 static const char s_extra_expression[] = "Extra expression in";
 
+/* The empty combination '()' is not allowed as an expression in scheme.  If
+ * it is detected in a place where an expression is expected, an 'Illegal
+ * empty combination' error is signalled.  Note: If you encounter this error
+ * message, it is very likely that you intended to denote the empty list.  To
+ * do so, you need to quote the empty list like (quote ()) or '().  */
+static const char s_empty_combination[] = "Illegal empty combination";
+
 /* Case or cond expressions must have at least one clause.  If a case or cond
  * expression without any clauses is detected, a 'Missing clauses' error is
  * signalled.  */
@@ -327,10 +339,7 @@ SCM_DEFINE (scm_dbg_iloc_p, "dbg-iloc?", 1, 0, 0,
 
 
 #define SCM_VALIDATE_NON_EMPTY_COMBINATION(x) \
-  do { \
+  ASSERT_SYNTAX (!SCM_EQ_P ((x), SCM_EOL), s_empty_combination, x)
-    if (SCM_EQ_P ((x), SCM_EOL)) \
-      scm_misc_error (NULL, s_expression, SCM_EOL); \
-  } while (0)
 
 
 
@@ -367,7 +376,7 @@ SCM_DEFINE (scm_dbg_iloc_p, "dbg-iloc?", 1, 0, 0,
 
 #define SCM_EVALIM2(x) \
   ((SCM_EQ_P ((x), SCM_EOL) \
-    ? scm_misc_error (NULL, s_expression, SCM_EOL), 0 \
+    ? syntax_error (s_empty_combination, (x), SCM_UNDEFINED), 0 \
     : 0), \
    (x))
 
@@ -394,7 +403,6 @@ SCM_DEFINE (scm_dbg_iloc_p, "dbg-iloc?", 1, 0, 0,
 SCM_REC_MUTEX (source_mutex);
 
 
-static const char s_expression[] = "missing or extra expression";
 static const char s_test[] = "bad test";
 static const char s_body[] = "bad body";
 static const char s_bindings[] = "bad bindings";
@@ -431,6 +439,18 @@ scm_ilookup (SCM iloc, SCM env)
 }
 
 
+SCM_SYMBOL (scm_unbound_variable_key, "unbound-variable");
+
+static void error_unbound_variable (SCM symbol) SCM_NORETURN;
+static void
+error_unbound_variable (SCM symbol)
+{
+  scm_error (scm_unbound_variable_key, NULL,
+	     "Unbound variable: ~S",
+	     scm_list_1 (symbol), SCM_BOOL_F);
+}
+
+
 /* The Lookup Car Race
     - by Eva Luator
 
@@ -504,8 +524,6 @@ scm_ilookup (SCM iloc, SCM env)
    for NULL.  I think I've found the only places where this
    applies. */
 
-SCM_SYMBOL (scm_unbound_variable_key, "unbound-variable");
-
 static SCM *
 scm_lookupcar1 (SCM vloc, SCM genv, int check)
 {
@@ -568,9 +586,7 @@ scm_lookupcar1 (SCM vloc, SCM genv, int check)
 	if (check)
 	  {
 	    if (SCM_NULLP (env))
-	      scm_error (scm_unbound_variable_key, NULL,
+              error_unbound_variable (var);
-			 "Unbound variable: ~S",
-			 scm_list_1 (var), SCM_BOOL_F);
 	    else
 	      scm_misc_error (NULL, "Damaged environment: ~S",
 			      scm_list_1 (var));
@@ -1840,6 +1856,7 @@ scm_m_expand_body (SCM xorig, SCM env)
   return xorig;
 }
 
+
 SCM
 scm_macroexp (SCM x, SCM env)
 {
@@ -2602,11 +2619,6 @@ dispatch:
   SCM_TICK;
   switch (SCM_TYP7 (x))
     {
-    case scm_tc7_symbol:
-      /* Only happens when called at top level.  */
-      x = scm_cons (x, SCM_UNDEFINED);
-      RETURN (*scm_lookupcar (x, env, 1));
-
     case SCM_BIT7 (SCM_IM_AND):
       x = SCM_CDR (x);
       while (!SCM_NULLP (SCM_CDR (x)))
@@ -3286,10 +3298,12 @@ dispatch:
 	  goto evapply;
 	}
 
+
     default:
       proc = x;
       goto evapply;
 
+
     case scm_tc7_vector:
     case scm_tc7_wvect:
 #if SCM_HAVE_ARRAYS
@@ -3315,6 +3329,11 @@ dispatch:
     case scm_tcs_struct:
       RETURN (x);
 
+    case scm_tc7_symbol:
+      /* Only happens when called at top level.  */
+      x = scm_cons (x, SCM_UNDEFINED);
+      RETURN (*scm_lookupcar (x, env, 1));
+
     case scm_tc7_variable:
       RETURN (SCM_VARIABLE_REF(x));
 

test-suite/ChangeLog

@@ -1,3 +1,13 @@
+2003-11-01  Dirk Herrmann  <D.Herrmann@tu-bs.de>
+
+	* tests/syntax.test (exception:missing/extra-expr-misc): Removed.
+
+	(exception:illegal-empty-combination): New.
+
+	(exception:missing/extra-expr): Unified capitalization.
+
+	Adapted test for '()' to the new way of error reporting.
+
 2003-10-19  Kevin Ryde  <user42@zip.com.au>
 
 	* tests/numbers.test: Use define-module to hide helper defines.

test-suite/tests/syntax.test

@@ -24,14 +24,14 @@
 (define exception:bad-expression
   (cons 'syntax-error "Bad expression"))
 
-(define exception:missing/extra-expr-misc
-  (cons 'misc-error "^missing or extra expression"))
 (define exception:missing/extra-expr
-  (cons 'syntax-error "missing or extra expression"))
+  (cons 'syntax-error "Missing or extra expression"))
 (define exception:missing-expr
   (cons 'syntax-error "Missing expression"))
 (define exception:extra-expr
   (cons 'syntax-error "Extra expression"))
+(define exception:illegal-empty-combination
+  (cons 'syntax-error "Illegal empty combination"))
 
 (define exception:bad-bindings
   (cons 'syntax-error "Bad bindings"))
@@ -86,7 +86,7 @@
 
     ;; Fixed on 2001-3-3
     (pass-if-exception "empty parentheses \"()\""
-      exception:missing/extra-expr-misc
+      exception:illegal-empty-combination
       (eval '()
 	    (interaction-environment)))))