[honu] add assignment operator

collects/honu/core/private/honu2.rkt

@@ -136,6 +136,13 @@
                   [right right])
       #'(right left))))
 
+(provide honu-assignment)
+(define-honu-operator/syntax honu-assignment 0.0001 'left
+  (lambda (left right)
+    (with-syntax ([left left]
+                  [right right])
+      #'(set! left right))))
+
 (define-binary-operator honu-+ 1 'left +)
 (define-binary-operator honu-- 1 'left -)
 (define-binary-operator honu-* 2 'left *)

collects/honu/core/read.rkt

@@ -34,7 +34,7 @@
                                          (:~ #\")))
 (define-lex-abbrev string (:: #\" (:* string-character) #\"))
 (define-lex-abbrev operator (:or "+" "=" "*" "/" "-" "^" "||" "|" "&&" "<="
-                                 ">=" "<-" "<" ">" "!" "::"))
+                                 ">=" "<-" "<" ">" "!" "::" ":="))
 (define-lex-abbrev block-comment (:: "/*"
                                      (complement (:: any-string "*/" any-string))
                                      "*/"))