From 70455ed3f8ae3423d4403351558476197e090447 Mon Sep 17 00:00:00 2001
From: Daphne Preston-Kendal <git@dpk.io>
Date: Tue, 15 Mar 2022 09:07:11 +0100
Subject: [PATCH] Revert "Implement identifier-syntax in init-7.scm"

This reverts commit d55d6c619c23c46a9c18b148f2702d283f55d1ea.
---
 lib/init-7.scm | 74 ++++++++------------------------------------------
 1 file changed, 12 insertions(+), 62 deletions(-)

diff --git a/lib/init-7.scm b/lib/init-7.scm
index c84b1ce0..d465bbbb 100644
--- a/lib/init-7.scm
+++ b/lib/init-7.scm
@@ -849,12 +849,12 @@
       (lambda () (current-output-port old-out)))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; syntax-rules and identifier-syntax
+;; syntax-rules
 
-(define (syntax-template-transformer rename compare id-syntax? ellipsis ellipsis-specified? lits forms)
-  (let ((count 0)
+(define (syntax-rules-transformer expr rename compare)
+  (let ((ellipsis-specified? (identifier? (cadr expr)))
+        (count 0)
         (_er-macro-transformer (rename 'er-macro-transformer))
-        (_er-macro-transformer* (rename 'er-macro-transformer*))
         (_lambda (rename 'lambda))      (_let (rename 'let))
         (_begin (rename 'begin))        (_if (rename 'if))
         (_and (rename 'and))            (_or (rename 'or))
@@ -874,12 +874,15 @@
         (_list->vector (rename 'list->vector))
         (_cons3 (rename 'cons-source))
         (_underscore (rename '_)))
+    (define ellipsis (if ellipsis-specified? (cadr expr) (rename '...)))
+    (define lits (if ellipsis-specified? (car (cddr expr)) (cadr expr)))
+    (define forms (if ellipsis-specified? (cdr (cddr expr)) (cddr expr)))
     (define (next-symbol s)
       (set! count (+ count 1))
       (rename (string->symbol (string-append s (%number->string count)))))
     (define (expand-pattern pat tmpl)
-      (let lp ((p (if id-syntax? pat (cdr pat)))
-               (x (if id-syntax? _expr (list _cdr _expr)))
+      (let lp ((p (cdr pat))
+               (x (list _cdr _expr))
                (dim 0)
                (vars '())
                (k (lambda (vars)
@@ -1069,7 +1072,7 @@
          ((null? t) (list _quote '()))
          (else t))))
     (list
-     (if id-syntax? _er-macro-transformer* _er-macro-transformer)
+     _er-macro-transformer
      (list _lambda (list _expr _rename _compare)
            (list
             _car
@@ -1080,7 +1083,7 @@
                (lambda (clause)
                  (if (and (list? clause) (= (length clause) 2))
                      (expand-pattern (car clause) (cadr clause))
-                     (error "invalid syntax rule, which must be of the form (pattern template) (note fenders are not supported)"
+                     (error "invalid syntax-rules clause, which must be of the form (pattern template) (note fenders are not supported)"
                             clause)))
                forms)
               (list
@@ -1092,60 +1095,7 @@
 (define-syntax syntax-rules
   (er-macro-transformer
    (lambda (expr rename compare)
-     (let ((ellipsis-specified? (identifier? (cadr expr))))
-       (let ((ellipsis (if ellipsis-specified? (cadr expr) (rename '...)))
-             (lits (if ellipsis-specified? (car (cddr expr)) (cadr expr)))
-             (forms (if ellipsis-specified? (cdr (cddr expr)) (cddr expr))))
-         (syntax-template-transformer rename compare
-                                      #f  ; not id-syntax?
-                                      ellipsis ellipsis-specified?
-                                      lits forms))))))
-
-(define-syntax identifier-syntax
-  (er-macro-transformer
-   (lambda (expr rename compare)
-     (let ((template (cadr expr))
-           (_er-macro-transformer* (rename 'er-macro-transformer*))
-           (_lambda (rename 'lambda)) (_expr (rename 'expr))
-           (_rename (rename 'rename)) (_compare (rename 'compare))
-           (_if (rename 'if))         (_pair? (rename 'pair?))
-           (_cons (rename 'cons))     (_cdr (rename 'cdr))
-           (_quote (rename 'syntax-quote))
-           (_make-variable-transformer (rename 'make-variable-transformer))
-           (_set! (rename 'set!))     (_o (rename 'o)))
-       (cond ((= (length expr) 2)
-              (list
-               _er-macro-transformer*
-               (list _lambda (list _expr _rename _compare)
-                     (list _if (list _pair? _expr)
-                           (list _cons
-                                 (list _quote template)
-                                 (list _cdr _expr))
-                           (list _quote template)))))
-             (else
-              (let* ((ellipsis-specified? (identifier? (cadr expr)))
-                     (ellipsis (if ellipsis-specified? (cadr expr) (rename '...)))
-                     (forms (if ellipsis-specified? (cddr expr) (cdr expr))))
-                (if (not (and (= (length forms) 2)
-                              (identifier? (caar forms))
-                              (compare (caar (cadr forms)) _set!)
-                              (identifier? (car (cdar (cadr forms))))))
-                    (error "invalid identifier-syntax clauses" forms)
-                    (list
-                     _make-variable-transformer
-                     (syntax-template-transformer
-                      rename compare
-                      #t     ; id-syntax?
-                      ellipsis ellipsis-specified?
-                      (list  ; lits, i.e. (set!)
-                       (caar (cadr forms))) 
-                      (list  ; forms
-                       (cadr forms)  ; set! form
-                       (list         ; application form
-                        (cons (caar forms) _o)
-                        (cons (cadr (car forms)) _o))
-                       (car forms))  ; bare identifier form
-                      ))))))))))
+     (syntax-rules-transformer expr rename compare))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; let(rec)-syntax and datum->syntax