Fix: nits; Catch EXTERN PRAGMA parse error and rethrow warning

src/ast.lisp

@@ -439,7 +439,7 @@ compilation passes."))
   ((name :reader extern-name
          :initarg :name
          :documentation "The name of the function."))
-  (:documentation "A function that operates on classical memory and values, declared to
+  (:documentation "A procedure that operates on classical memory and values, declared to
 be available in the underlying system."))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Definitions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -1126,17 +1126,21 @@ Each addressing mode will be a vector of symbols:
 (defclass call (classical-instruction)
   ((extern
     :initarg :extern
-    :reader call-extern)
+    :reader call-extern
+    :type extern
+    :documentation "The extern to be called.")
    (arguments
     :initarg :arguments
-    :reader call-arguments)))
+    :reader call-arguments
+    :documentation "A list of memory refs and constant values"))
+  (:documentation "A call to an EXTERN function."))
 
 (defmethod mnemonic ((call call))
   (declare (ignore call))
   (values "CALL" 'call))
 
 (defmethod arguments ((call call))
-  (map 'vector #'identity (cons (call-extern call) (call-arguments call))))
+  (coerce (cons (call-extern call) (call-arguments call)) 'vector))
 
 (defclass jump (instruction)
   ((label :initarg :label