Macro expansion working properly.

[scheme.forth.jl.git] / src / scheme.4th

diff --git a/src/scheme.4th b/src/scheme.4th
index 1068229..ec97f09 100644 (file)
--- a/src/scheme.4th
+++ b/src/scheme.4th
@@ -10,6 +10,7 @@ include float.4th
 include debugging.4th
 
 defer read
+defer expand
 defer eval
 defer print
 
@@ -261,8 +262,8 @@ create-symbol ok                ok-symbol
 create-symbol if                if-symbol
 create-symbol lambda            lambda-symbol
 create-symbol λ                 λ-symbol
-create-symbol begin             begin-symbol
 create-symbol eof               eof-symbol
+create-symbol no-match          no-match-symbol
 
 \ Symbol to be bound to welcome message procedure by library
 create-symbol welcome           welcome-symbol
@@ -1403,34 +1404,21 @@ defer eval-quasiquote-item
 : definition? ( obj -- obj bool )
     define-symbol tagged-list? ;
 
-: make-lambda ( params body -- lambda-exp )
-    lambda-symbol -2rot cons cons ;
-
-( Handles iterative expansion of defines in
-  terms of nested lambdas. Most Schemes only
-  handle one iteration of expansion! )
-: definition-var-val ( obj -- var val )
-
-    cdr 2dup cdr 2swap car ( val var )
-
-    begin
-        symbol-type istype? false =
-    while
-        2dup cdr 2swap car ( val formals var' )
-        -2rot 2swap ( var' formals val )
-        make-lambda nil cons ( var' val' )
-        2swap ( val' var' )
-    repeat
+: definition-var ( obj -- var )
+    cdr car ;
 
-    2swap car
-;
+: definition-val ( obj -- val )
+    cdr cdr car ;
 
 : eval-definition ( obj env -- res )
-    2dup 2rot ( env env obj )
-    definition-var-val ( env env var val )
-    2rot eval  ( env var val )
+    2swap
+    2over 2over
+    definition-val 2swap
+    eval
 
-    2rot ( var val env )
+    2swap definition-var 2swap
+
+    2rot
     define-var
 
     ok-symbol
@@ -1524,12 +1512,6 @@ hide env
 : lambda-body ( obj -- body )
     cdr cdr ;
 
-: begin? ( obj -- obj bool )
-    begin-symbol tagged-list? ;
-
-: begin-actions ( obj -- actions )
-    cdr ;
-
 : eval-sequence ( explist env -- finalexp env )
     ( Evaluates all bar the final expressions in
       an an expression list. The final expression
@@ -1724,12 +1706,6 @@ hide env
         exit
     then
 
-    begin? if
-        begin-actions 2swap
-        eval-sequence
-        ['] eval goto-deferred
-    then
-
     application? if
 
         2over 2over ( env exp env exp )
@@ -1766,7 +1742,119 @@ hide env
     extend-env eval-sequence eval
 ;
 
+: expand-macro ( exp -- result )
+    pair-type istype? invert if exit then
+    2dup car symbol-type istype? invert if 2drop exit then
+    
+    lookup-macro nil? if
+        2drop exit then
+
+    2over cdr macro-eval
+
+    2dup no-match-symbol objeq? if
+        2drop exit
+    else
+        2swap 2drop
+    then
+
+    R> drop ['] expand goto-deferred
+;
+
+: expand-quasiquote-item ( exp -- result )
+    nil? if exit then
+
+    unquote? if
+        unquote-symbol 2swap cdr car expand nil cons cons
+        exit
+    then
+
+    unquote-splicing? if
+        unquote-splicing-symbol 2swap cdr car expand nil cons cons
+        exit
+    then
+    
+    pair-type istype? if
+        2dup car recurse
+        2swap cdr recurse
+        cons
+    then
+;
+
+: expand-quasiquote ( exp -- result )
+    quasiquote-symbol 2swap cdr
+
+    expand-quasiquote-item
+
+    cons ;
+
+: expand-definition ( exp -- result )
+    define-symbol 2swap
+
+    2dup definition-var
+    2swap definition-val expand
+    nil ( define var val' nil )
+
+    cons cons cons ;
+
+: expand-assignment ( exp -- result )
+    set!-symbol 2swap
+
+    2dup assignment-var
+    2swap assignment-val expand
+    nil ( define var val' nil )
+
+    cons cons cons ;
+
+: expand-list ( exp -- res )
+    nil? if exit then
+
+    2dup car expand
+    2swap cdr recurse
+
+    cons ;
+
+: macro-definition-nameparams
+    cdr car ;
+
+: expand-define-macro ( exp -- res )
+    define-macro-symbol 2swap
+    2dup macro-definition-nameparams
+    2swap macro-definition-body expand-list
+
+    cons cons ;
+
+: expand-lambda ( exp -- res )
+    lambda-symbol 2swap
+    2dup lambda-parameters
+    2swap lambda-body expand-list
+
+    cons cons ;
+
+: expand-if ( exp -- res )
+    if-symbol 2swap
+    
+    2dup if-predicate expand
+    2swap 2dup if-consequent expand
+    2swap if-alternative none? if
+        2drop nil
+    else
+        expand nil cons
+    then
+
+    cons cons cons ;
+
+: expand-application ( exp -- res )
+    2dup operator expand
+    2swap operands expand-list
+
+    cons ;
+
 :noname ( exp -- result )
+    expand-macro
+
+    self-evaluating? if exit then
+
+    quote? if exit then
 
     quasiquote? if expand-quasiquote exit then
 
@@ -1776,13 +1864,11 @@ hide env
 
     macro-definition? if expand-define-macro exit then
 
-    if? if expand-if exit then
-
     lambda? if expand-lambda exit then
 
-    begin? if expand-sequence exit then
+    if? if expand-if exit then
 
-    application? if expand-apply exit then
+    application? if expand-application exit then
 
 ; is expand
 
@@ -2024,7 +2110,7 @@ variable gc-stack-depth
 
     include scheme-primitives.4th
 
-\    s" scheme-library.scm" load 2drop
+    s" scheme-library.scm" load 2drop
     
 \ }}}
 
@@ -2057,7 +2143,7 @@ variable gc-stack-depth
     enable-gc
 
     \ Display welcome message
-    \ welcome-symbol nil cons global-env obj@ eval 2drop
+    welcome-symbol nil cons global-env obj@ eval 2drop
 
     begin
         ['] repl-body catch