From 6ffa3538cfeb5a97e967544bfbbcf907f4aa565f Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rhogenson@posteo.net>
Date: Sat, 30 Jul 2022 13:31:05 -0700
Subject: Add call-builtin syntax.

This syntax allows calling opcodes directly from scheme code.
Very powerful technique.
---
 csc/macros.csc | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

(limited to 'csc/macros.csc')

diff --git a/csc/macros.csc b/csc/macros.csc
index 288865d..4559991 100644
--- a/csc/macros.csc
+++ b/csc/macros.csc
@@ -32,6 +32,7 @@
             library-ref-name
             library-ref?
             make-call
+            make-call-builtin
             make-constant
             make-define-syntax
             make-lambda
@@ -748,6 +749,24 @@
             (_ (raise-syntax-error "unexpected form in builtin-define-syntax" x))))))
 
 
+    (define builtin-call-builtin
+      (make-macro-transformer
+        (lambda (x)
+          (syntax-case x
+            ((_ op . args) when (identifier? op)
+              (make-call-builtin (identifier-name op)
+                                 (let loop ((args args)
+                                            (expanded-args '()))
+                                   (syntax-case args
+                                     ('() (reverse expanded-args))
+                                     ((head . tail)
+                                       (loop tail
+                                             (cons (expand-syntax-object head)
+                                                   expanded-args)))
+                                     (_ (raise-syntax-error "unexpected form in call-builtin"))))))
+            (_ (raise-syntax-error "unexpected form in call-builtin" x))))))
+
+
     (define builtins-environment
       (alist->substitutions
         (list (cons 'syntax-rules builtin-syntax-rules)
@@ -757,7 +776,8 @@
               (cons 'quote builtin-quote)
               (cons 'lambda builtin-lambda)
               (cons 'builtin-define builtin-define)
-              (cons 'define-syntax builtin-define-syntax))))
+              (cons 'define-syntax builtin-define-syntax)
+              (cons 'call-builtin builtin-call-builtin))))
 
 
     ; Expands the body of a library, or top level. expand-body can be thought
-- 
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