add reader syntax for []

Now [...] reads to (¤ ...) for easy semantic processing

sex-reader.scm

@@ -2,9 +2,15 @@
 
 (include "utils.macros.scm")
 
-(import (chicken pathname)
-        brev-separate
-        fmt)
+(import
+  (chicken base)
+  (chicken io)
+  (chicken pathname)
+  (chicken port)
+  (chicken read-syntax)
+  (chicken string)
+  brev-separate
+  fmt)
 
 (define (read-forms acc)
   (let ((r (read)))
@@ -16,7 +22,41 @@
     (with-input-from-file (pathname-strip-directory file)
       (fn (read-forms (list))))))
 
+(define (read-bracket port)
+  (let loop ((c (read-char port))
+             (str (string)))
+    (cond ((char=? c #\])
+           (cons '¤
+                 (with-input-from-string str
+                   (fn (port-map identity read)))))
+          ((char=? c #\[)
+           (loop port (conc )))
+          (else
+           (loop (read-char port)
+                 (conc str c))))))
+
+(define open-bracket-counter (make-parameter 0))
+
 (define (read-raw-forms input-source)
+  (let ((bracket-end (gensym)))
+   (set-read-syntax!
+    #\]
+    (lambda (port)
+      (when (= 0 (open-bracket-counter))
+        (error "Unmatched closing bracket"))
+      (open-bracket-counter (- (open-bracket-counter) 1))
+      bracket-end))
+
+   (set-read-syntax!
+    #\[
+    (lambda (port)
+      (open-bracket-counter (+ (open-bracket-counter) 1))
+      (let loop ((r (read port))
+                 (acc (list)))
+        (if (eq? r bracket-end)
+            (cons '¤ (reverse acc))
+            (loop (read port)
+                  (cons r acc)))))))
   (if (eq? input-source 'stdin)
       (read-forms (list))
       (read-from-file input-source)))