parser.rkt

#lang brag

i-program : (i-statement)*

; statements syntax

@i-statement : i-assign | i-if | i-skip | i-while | i-print
i-assign     : i-id /"=" i-exp /";"
@i-block     : /"{" (i-statement)* /"}"
i-condition  : /"(" i-exp /")" 
i-if         : /"if" i-condition i-block /"else" i-block
i-skip       : /"skip" /";"
i-while      : /"while" /"(" i-exp /")" i-block
i-print      : /"print" i-exp /";"

; expression syntax

i-exp      : @i-or-exp
i-or-exp   : [i-or-exp "||"] @i-and-exp
i-and-exp  : [i-and-exp "&&"] @i-not-exp
i-not-exp  : ["!"] @i-comp-exp
i-comp-exp : [i-comp-exp ("=" | "<")] @i-sum
i-sum      : [i-sum ("+" | "-")] @i-product
i-product  : [i-product ("*" | "/" | "%")] @i-neg
i-neg      : ["-"] @i-expt
i-expt     : [i-expt ("^")] i-value
@i-value   : i-number | i-id | /"(" i-exp /")"
@i-number  : INTEGER
@i-id      : ID