Removing 'begin' as a macro, doing it as a special form

extra/lisp/lisp-tests.factor

@@ -67,14 +67,6 @@ IN: lisp.test
         "(list 1 2 (list 3 (list 4) 5))" lisp-eval cons>seq
     ] unit-test
     
-    { T{ lisp-symbol f "begin" } } [
-        "(defmacro begin (&rest body) (list (cons (quote lambda) (cons (list) body))))" lisp-eval
-    ] unit-test
-    
-    { t } [
-        T{ lisp-symbol f "begin" } lisp-macro?
-    ] unit-test
-    
     { 5 } [
         "(begin (+ 1 4))" lisp-eval
     ] unit-test
@@ -84,7 +76,7 @@ IN: lisp.test
     ] unit-test
     
     { T{ lisp-symbol f "if" } } [
-        "(defmacro if (pred tr fl) (list (list (quote cond) (list pred tr) (list (quote #t) fl))))" lisp-eval
+        "(defmacro if (pred tr fl) (list (quote cond) (list pred tr) (list (quote #t) fl)))" lisp-eval
     ] unit-test
     
     { t } [

extra/lisp/lisp.factor

@@ -64,12 +64,17 @@ PRIVATE>
 : macro-expand ( cons -- quot )
     uncons [ list>seq >quotation ] [ lookup-macro ] bi* call convert-form ;
     
+: convert-begin ( cons -- quot )    
+    cdr [ convert-form ] [ ] lmap-as [ 1 tail* ] [ but-last ] bi
+    [ [ drop ] compose ] map prepend '[ , [ call ] each ] ;
+
 : form-dispatch ( cons lisp-symbol -- quot )
     name>>
     { { "lambda" [ convert-lambda ] }
       { "defmacro" [ convert-defmacro ] }
       { "quote" [ convert-quoted ] }
       { "cond" [ convert-cond ] }
+      { "begin" [ convert-begin ] }
      [ drop convert-general-form ]
     } case ;