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#lang br
( require " goto.rkt " )
( provide b-if b-comp-expr b-logic-expr )
;; b-if : /"if" b-expr /"then" b-expr [/"else" b-expr]
( define ( b-if cond-expr then-expr [ else-expr #f ] )
( cond
[ ( not ( zero? cond-expr ) ) ( b-goto then-expr ) ]
[ else-expr => b-goto ] ) )
( define bool-int ( λ ( val ) ( if val 1 0 ) ) )
( define bi= ( compose1 bool-int = ) )
( define bi< ( compose1 bool-int < ) )
( define bi> ( compose1 bool-int > ) )
;; b-comp-expr : b-cond-expr [("and" | "or") b-cond-expr]
( define-macro-cases b-logic-expr
[ ( _ ARG ) #' ARG ]
[ ( _ LEFT " and " RIGHT ) #' ( and LEFT RIGHT ) ]
[ ( _ LEFT " or " RIGHT ) #' ( or LEFT RIGHT ) ] )
;; b-cond-expr : b-expr [("=" | "<" | ">") b-expr]
( define-macro-cases b-comp-expr
[ ( _ ARG ) #' ARG ]
[ ( _ LEFT " = " RIGHT ) #' ( bi= LEFT RIGHT ) ]
[ ( _ LEFT " < " RIGHT ) #' ( bi< LEFT RIGHT ) ]
[ ( _ LEFT " > " RIGHT ) #' ( bi> LEFT RIGHT ) ] )