update repl handling

beautiful-racket-demo/basic-demo-3/misc.rkt

@@ -1,6 +1,6 @@
 #lang br
-(require "struct.rkt")
+(require "struct.rkt" "expr.rkt")
-(provide b-rem b-print b-let b-input b-statements b-require)
+(provide b-rem b-print b-let b-input b-repl b-require)
 
 (define (b-rem val) (void))
 
@@ -14,6 +14,10 @@
                      [num (string->number (string-trim str))])
                 (or num str))))
 
-(define-macro (b-statements STMT ...) #'(begin STMT ...))
+(define-macro (b-repl . ARGS)
+  (with-pattern ([STMTS (pattern-case-filter #'ARGS
+                          [(b-expr . EXPR-ARGS) #'(b-print (b-expr . EXPR-ARGS))]
+                          [OTHER-STMT #'OTHER-STMT])])
+    #'(begin . STMTS)))
 
 (define-macro (b-require ID) #'(void))

beautiful-racket-demo/basic-demo-3/parser.rkt

@@ -1,13 +1,12 @@
 #lang brag
 b-program : [b-line] (/NEWLINE [b-line])* | b-statement /NEWLINE
-b-line : b-line-num b-statements [b-rem]
+b-line : b-line-num [b-statement] (/":" [b-statement])* [b-rem]
 @b-line-num : INTEGER
 b-rem : REM
-@b-statements : [b-statement] (/":" [b-statement])*
 @b-statement : b-end | b-print | b-goto
              | b-let | b-input | b-if
              | b-gosub | b-return | b-for | b-next
-             | b-def | b-require | b-expr
+             | b-def | b-require
 b-end : /"end"
 b-print : /"print" [b-printable] (/";" [b-printable])*
 @b-printable : STRING | b-expr
@@ -38,3 +37,4 @@ b-expt : [b-expt ("^")] b-value
 b-func : ID /"(" b-input-list /")"
 @b-input-list : (ID | b-expr) [/"," (ID | b-expr)]*
 @b-number : INTEGER | DECIMAL
+b-repl : (b-statement | b-expr) (/":" [b-repl])*

beautiful-racket-demo/basic-demo-3/runtime.rkt

@@ -4,7 +4,7 @@
 
 (define basic-output-port (make-parameter (open-output-nowhere)))
 
-(define statement-parser (make-rule-parser b-statements))
+(define repl-parser (make-rule-parser b-repl))
 
 (define (configure-this!)
   (basic-output-port (current-output-port))
@@ -13,7 +13,7 @@
     (define one-line (read-line port))
     (if (eof-object? one-line)
         eof
-        (statement-parser (make-tokenizer (open-input-string one-line)))))
+        (repl-parser (make-tokenizer (open-input-string one-line)))))
   (current-read-interaction read-one-line))