From: Tim Vaughan <tgvaughan@gmail.com>
Date: Mon, 19 Jun 2017 09:32:43 +0000 (+1200)
Subject: Macro expansion working properly.
X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=commitdiff_plain;h=724ff46a1b082bef48b310a85d5a82037c2a914c;p=scheme.forth.jl.git

Macro expansion working properly.

begin is now a library form too.
---

diff --git a/src/scheme-derived-forms.scm b/src/scheme-derived-forms.scm
deleted file mode 100644
index 010519d..0000000
--- a/src/scheme-derived-forms.scm
+++ /dev/null
@@ -1,14 +0,0 @@
-;; define (procedural syntax)
-
-; Due to recursive macro expansion, this definition also allows
-; for curried function definitions.
-
-(define-macro (define args . body)
-              (if (pair? args)
-                `(define ,(car args) (lambda ,(cdr args) ,@body))
-                'no-match))
-
-;; Macro expansion test code
-
-(define-macro (test)
-              '(begin (display "Hello!") (newline)))
diff --git a/src/scheme-library.scm b/src/scheme-library.scm
index a420c70..67ab483 100644
--- a/src/scheme-library.scm
+++ b/src/scheme-library.scm
@@ -1,26 +1,127 @@
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Standard Library Procedures and Macros ;; 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; DERIVED FORMS
 
-;; MISC
+;; define (procedural syntax)
+
+(define-macro (define args . body)
+              (if (pair? args)
+                `(define ,(car args) (lambda ,(cdr args) ,@body))
+                'no-match))
+
+;; begin
+
+(define-macro (begin . sequence)
+              `((lambda () ,@sequence)))
+
+;; caddr etc.
+
+(define-macro (caar l) `(car (car ,l)))
+(define-macro (cadr l) `(car (cdr ,l)))
+(define-macro (cdar l) `(cdr (car ,l)))
+(define-macro (cddr l) `(cdr (cdr ,l)))
+(define-macro (caaar l) `(car (car (car ,l))))
+(define-macro (caadr l) `(car (car (cdr ,l))))
+(define-macro (cadar l) `(car (cdr (car ,l))))
+(define-macro (caddr l) `(car (cdr (cdr ,l))))
+(define-macro (cdaar l) `(cdr (car (car ,l))))
+(define-macro (cdadr l) `(cdr (car (cdr ,l))))
+(define-macro (cddar l) `(cdr (cdr (car ,l))))
+(define-macro (cdddr l) `(cdr (cdr (cdr ,l))))
+(define-macro (cadddr l) `(car (cdr (cdr (cdr ,l)))))
+
+
+;; Methods used in remaining macro definitions:
+
+(define (map proc l)
+  (if (null? l)
+    '()
+    (cons (proc (car l)) (map proc (cdr l)))))
+
+;; let
+
+(define-macro (let args . body)
+              `((lambda ,(map (lambda (x) (car x)) args)
+                 ,@body) ,@(map (lambda (x) (cadr x)) args)))
+
+;; let*
+
+(define-macro (let* args . body)
+              (if (null? args)
+                `(let () ,@body)
+                `(let (,(car args))
+                   (let* ,(cdr args) ,@body))))
+
+;; while
+
+(define-macro (while condition . body)
+              (let ((loop (gensym)))
+                `(begin
+                   (define (,loop)
+                     (if ,condition
+                       (begin ,@body (,loop))))
+                   (,loop))))
+
+;; cond
+
+((lambda ()
+   (define (cond-predicate clause) (car clause))
+   (define (cond-actions clause) (cdr clause))
+   (define (cond-else-clause? clause)
+     (eq? (cond-predicate clause) 'else))
+
+   (define (expand-clauses clauses)
+     (if (null? clauses)
+       (none)
+       (let ((first (car clauses))
+             (rest (cdr clauses)))
+         (if (cond-else-clause? first)
+           (if (null? rest)
+             `(begin ,@(cond-actions first))
+             (error "else clause isn't last in cond expression."))
+           `(if ,(cond-predicate first)
+              (begin ,@(cond-actions first))
+              ,(expand-clauses rest))))))
 
-(define (not x) (if x #f #t))
+   (define-macro (cond . clauses)
+                 (if (null? clauses)
+                   (error "cond requires at least one clause.")
+                   (expand-clauses clauses)))))
+
+;; and
+
+((lambda ()
+   (define (expand-and-expressions expressions)
+     (let ((first (car expressions))
+           (rest (cdr expressions)))
+       (if (null? rest)
+         first
+         `(if ,first
+            ,(expand-and-expressions rest)
+            #f))))
 
-(define (list . args) args)
+   (define-macro (and . expressions)
+                 (if (null? expressions)
+                   #t
+                   (expand-and-expressions expressions)))
+   ))
+
+;; or
+
+((lambda ()
+   (define (expand-or-expressions expressions)
+     (if (null? expressions)
+       #f
+       (let ((first (car expressions))
+             (rest (cdr expressions))
+             (val (gensym)))
+         `(let ((,val ,first))
+            (if ,val
+              ,val
+              ,(expand-or-expressions rest))))))
+
+   (define-macro (or . expressions)
+                 (expand-or-expressions expressions))
+   ))
 
-(define (caar l) (car (car l)))
-(define (cadr l) (car (cdr l)))
-(define (cdar l) (cdr (car l)))
-(define (cddr l) (cdr (cdr l)))
-(define (caaar l) (car (car (car l))))
-(define (caadr l) (car (car (cdr l))))
-(define (cadar l) (car (cdr (car l))))
-(define (caddr l) (car (cdr (cdr l))))
-(define (cdaar l) (cdr (car (car l))))
-(define (cdadr l) (cdr (car (cdr l))))
-(define (cddar l) (cdr (cdr (car l))))
-(define (cdddr l) (cdr (cdr (cdr l))))
-(define (cadddr l) (car (cdr (cdr (cdr l)))))
 
 ;; FUNCTIONAL PROGRAMMING
 
@@ -36,10 +137,6 @@
       (car l)
       (fold-left proc (proc (car l) (car (cdr l))) (cdr (cdr l))))))
 
-(define (map proc l)
-  (if (null? l)
-    '()
-    (cons (proc (car l)) (map proc (cdr l)))))
 
 ;; NUMBERS
 
@@ -214,6 +311,7 @@
     (if (flonum? x) #t
       (if (ratnum? x) #t #f))))
 
+
 ;; LISTS
 
 ; Return number of items in list
@@ -245,101 +343,8 @@
     (append (reverse (cdr l)) (list (car l)))))
 
 
-;; LIBRARY SPECIAL FORMS
-
-; let
-
-(define-macro (let args . body)
-              `((lambda ,(map (lambda (x) (car x)) args)
-                 ,@body) ,@(map (lambda (x) (cadr x)) args)))
-
-; let*
-
-(define-macro (let* args . body)
-              (if (null? args)
-                `(let () ,@body)
-                `(let (,(car args))
-                   (let* ,(cdr args) ,@body))))
-
-; while
-
-(define-macro (while condition . body)
-              (let ((loop (gensym)))
-                `(begin
-                   (define (,loop)
-                     (if ,condition
-                       (begin ,@body (,loop))))
-                   (,loop))))
-
-; cond
-
-((lambda ()
-   (define (cond-predicate clause) (car clause))
-   (define (cond-actions clause) (cdr clause))
-   (define (cond-else-clause? clause)
-     (eq? (cond-predicate clause) 'else))
-
-   (define (expand-clauses clauses)
-     (if (null? clauses)
-       (none)
-       (let ((first (car clauses))
-             (rest (cdr clauses)))
-         (if (cond-else-clause? first)
-           (if (null? rest)
-             `(begin ,@(cond-actions first))
-             (error "else clause isn't last in cond expression."))
-           `(if ,(cond-predicate first)
-              (begin ,@(cond-actions first))
-              ,(expand-clauses rest))))))
-
-   (define-macro (cond . clauses)
-                 (if (null? clauses)
-                   (error "cond requires at least one clause.")
-                   (expand-clauses clauses)))
-   ))
-
-; and
-
-((lambda ()
-   (define (expand-and-expressions expressions)
-     (let ((first (car expressions))
-           (rest (cdr expressions)))
-       (if (null? rest)
-         first
-         `(if ,first
-            ,(expand-and-expressions rest)
-            #f))))
-
-   (define-macro (and . expressions)
-                 (if (null? expressions)
-                   #t
-                   (expand-and-expressions expressions)))
-   ))
-
-; or
-
-((lambda ()
-   (define (expand-or-expressions expressions)
-     (if (null? expressions)
-       #f
-       (let ((first (car expressions))
-             (rest (cdr expressions))
-             (val (gensym)))
-         `(let ((,val ,first))
-            (if ,val
-              ,val
-              ,(expand-or-expressions rest))))))
-
-   (define-macro (or . expressions)
-                 (expand-or-expressions expressions))
-   ))
-
-
 ;; TESTING
 
-(define-macro (backwards . body)
-              (cons 'begin (reverse body)))
-
 ; Test for the while macro.
 (define (count)
   (define counter 10)
@@ -365,6 +370,8 @@
     0
     (fix:+ n (sum-recurse (fix:- n 1)))))
 
+
+
 ;; MISC
 
 (define (license)
diff --git a/src/scheme.4th b/src/scheme.4th
index 9b5eb27..ec97f09 100644
--- 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
 
@@ -261,7 +262,6 @@ 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
 
@@ -1512,12 +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
@@ -1712,12 +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 )
@@ -1754,8 +1742,6 @@ hide env
     extend-env eval-sequence eval
 ;
 
-defer expand
-
 : expand-macro ( exp -- result )
     pair-type istype? invert if exit then
     2dup car symbol-type istype? invert if 2drop exit then
@@ -1778,11 +1764,16 @@ defer expand
     nil? if exit then
 
     unquote? if
-        unquote-symbol 2swap cdr expand nil cons cons
+        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? if
+    pair-type istype? if
         2dup car recurse
         2swap cdr recurse
         cons
@@ -1847,25 +1838,18 @@ defer expand
     2swap if-alternative none? if
         2drop nil
     else
-        nil cons
+        expand nil cons
     then
 
     cons cons cons ;
 
-: expand-begin ( exp -- res )
-    begin-symbol 2swap
-    begin-actions expand-list
-
-    cons ;
-
 : expand-application ( exp -- res )
-    2dup operator
+    2dup operator expand
     2swap operands expand-list
 
     cons ;
 
 :noname ( exp -- result )
-
     expand-macro
 
     self-evaluating? if exit then
@@ -1884,8 +1868,6 @@ defer expand
 
     if? if expand-if exit then
 
-    begin? if expand-begin exit then
-
     application? if expand-application exit then
 
 ; is expand
@@ -2128,9 +2110,7 @@ variable gc-stack-depth
 
     include scheme-primitives.4th
 
-    s" scheme-derived-forms.scm" load 2drop
-
-\    s" scheme-library.scm" load 2drop
+    s" scheme-library.scm" load 2drop
     
 \ }}}
 
@@ -2163,7 +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