34 lines
600 B
Standard ML
34 lines
600 B
Standard ML
|
structure BraceDfa =
|
||
|
|
struct
|
||
|
|
val dead = 0
|
||
|
|
val start = 1
|
||
|
|
val final = 2
|
||
|
|
|
||
|
|
fun makeStart i =
|
||
|
|
let
|
||
|
|
val chr = Char.chr i
|
||
|
|
in
|
||
|
|
if chr = #"{" orelse chr = #"}" then
|
||
|
|
final
|
||
|
|
else
|
||
|
|
dead
|
||
|
|
end
|
||
|
|
|
||
|
|
val deadTable = SpaceDfa.deadTable
|
||
|
|
val startTable = Vector.tabulate (255, makeStart)
|
||
|
|
val finalTable = deadTable
|
||
|
|
|
||
|
|
val tables = #[deadTable, startTable, finalTable]
|
||
|
|
|
||
|
|
fun isFinal state =
|
||
|
|
state = final
|
||
|
|
|
||
|
|
fun next (state, chr) =
|
||
|
|
let
|
||
|
|
val table = Vector.sub (tables, state)
|
||
|
|
val idx = Char.ord chr
|
||
|
|
in
|
||
|
|
Vector.sub (table, idx)
|
||
|
|
end
|
||
|
|
end
|