From d917f41beca176b8f2b682ac3a2c25b148752b71 Mon Sep 17 00:00:00 2001
From: Thomas Albers Raviola <thomas@thomaslabs.org>
Date: Wed, 15 May 2024 16:21:29 +0200
Subject: Add syntax form for writing macros

* src/core.lisp (syntax): Change evaluation rules to replace arguments inside
macro expansion.
* src/eval.lisp (tree-eval): Add Evaluation route for chains with a syntax
closure.
* t/test4.chn: New file.
---
 src/core.lisp | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

(limited to 'src/core.lisp')

diff --git a/src/core.lisp b/src/core.lisp
index 6c151ce..d3c396b 100644
--- a/src/core.lisp
+++ b/src/core.lisp
@@ -16,7 +16,9 @@
                        ,@body)
                    ',args
                    nil
-                   (complement #'identity))))
+                   (complement #'identity)
+                   nil
+                   :function)))
 
 (defmacro define-function* (name (&rest args) (siblings group-predicate)
                             &body body)
@@ -24,14 +26,18 @@
                      ,@body)
                  ',args
                  nil
-                 ,group-predicate))
+                 ,group-predicate
+                 nil
+                 :function))
 
 (defmacro define-syntax (name (&rest args) &body body)
   `(make-closure #'(lambda (environment siblings ,@args)
                      ,@body)
                  ',args
                  t
-                 (complement #'identity)))
+                 (complement #'identity)
+                 nil
+                 :special))
 
 (defmacro define-syntax* (name (&rest args) (siblings group-predicate)
                           &body body)
@@ -39,7 +45,9 @@
                      ,@body)
                  ',args
                  t
-                 ,group-predicate))
+                 ,group-predicate
+                 nil
+                 :special))
 
 (defparameter *lambda*
   (define-syntax lambda (arglist body)
@@ -52,8 +60,9 @@
                                             env
                                             environment)
                                     body))
-                     arglist nil (complement #'identity) env))))
+                     arglist nil (complement #'identity) env :function))))
 
+;; Is this basically quasiquote?
 (defparameter *syntax*
   (define-syntax syntax (arglist body)
     (setf arglist (remove-if #'whitespace-text-p arglist))
@@ -61,11 +70,14 @@
     (setf arglist (mapcar #'cdr arglist))
     (let ((env environment))
       (make-closure  #'(lambda (environment siblings &rest args)
-                         (tree-eval (append (pairlis arglist args)
-                                            env
-                                            environment)
-                                    body))
-                     arglist t (complement #'identity) env))))
+                         (mapc #'(lambda (pair)
+                                   (setf body (nsubst (cdr pair)
+                                                      `((symbol . ,(car pair)))
+                                                      body
+                                                      :test #'equal)))
+                               (pairlis arglist args))
+                         body)
+                     arglist t (complement #'identity) env :syntax))))
 
 (defparameter *define*
   (define-syntax* define (name value) (siblings #'identity)
-- 
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