Add SRFI 89 reader directives

reader-directive.scm

@@ -10,10 +10,18 @@
 (purpose "change to case insensitive identifiers")
 (rnrs r7rs)
 
+(directive "#!key")
+(purpose "start keyword arguments in lambda list")
+(srfi 89)
+
 (directive "#!no-fold-case")
 (purpose "change to case sensitive identifiers")
 (rnrs r7rs)
 
+(directive "#!optional")
+(purpose "start optional arguments in lambda list")
+(srfi 89)
+
 (directive "#!r6rs")
 (purpose "change to R6RS read syntax")
 (rnrs r6rs)
@@ -21,3 +29,7 @@
 (directive "#!r7rs")
 (purpose "change to R7RS read syntax")
 (implementations gauche)
+
+(directive "#!rest")
+(purpose "start rest argument in lambda list")
+(srfi 89)