grammar

public <top> = (<request> | <response>) [<polite>]

<request> = [<greeting>] (<navigate> | <browse>)
<response> = <confirm> | [(Which | Where) <aux_verb> | Show me] [<det>] <proximity> | <item> | <food_drink_desc>

<navigate> = (I <want> to <buy> [<det>] <item> | <way> <place>) {command = direction}
<browse> = (What | How many) [<shop_type>] shops are (there | available) {command = browse}

<greeting> = Hello | Hi | Hey 
<confirm> = <yes> | <no>
<yes> = Yes | Yeah | Yep | Okay {confirm = yes}
<no> = No | Nope | Nah | Not really {confirm = no}
<aux_verb> = is
<det> = a | an | the | some
<proximity> = <close_by> | <far_away>
<close_by> = closest | nearest {proximity = close}
<far_away> = furthest {proximity = far}
<item> = coffee | clothes | sandwiches | toys | music | jewellery | sports equipment
<food_drink_desc> = hot | cold | fast | cooked
<want> = want | would like | wish
<buy> = buy | purchase | get 
<place> = <det> (<shop> | <amenity> | <proximity>)
<shop_type> = coffee | clothes | sandwich | toy | book | music | sport | jewellery | department
<amenity> = ([mens | womens] toilet) | exit
<direction> = how to get | the (way | direction) 
<explain> = (explain to | tell) me
<polite> =  kindly | thank you | please
<shop> = [<shop_type>] shop
<way> = ([(Can | Could) you] <explain> <direction> to) | Where <aux_verb>