29 lines
818 B
Standard ML
29 lines
818 B
Standard ML
|
structure Scanner =
|
||
|
|
struct
|
||
|
|
structure Dfa = CaseSesitiveDfa
|
||
|
|
|
||
|
|
val intDfa = Dfa.fromString "[0-9]+"
|
||
|
|
val wordDfa = Dfa.fromString "0w[0-9]+"
|
||
|
|
val realDfa = "[0-9]+.[0-9]+"
|
||
|
|
val idDfa = Dfa.fromString "[a-zA-Z][a-zA-Z0-9_']*"
|
||
|
|
|
||
|
|
fun helpExtractString (pos, str, acc) =
|
||
|
|
if pos >= String.size str then
|
||
|
|
raise Fail ("unterminated string: [" ^ acc ^ "]\n")
|
||
|
|
else
|
||
|
|
case String.sub (str, pos) of
|
||
|
|
#"\"" => (pos + 1, acc)
|
||
|
|
| #"\\" =>
|
||
|
|
if pos + 1 >= String.size str then
|
||
|
|
raise Fail ("unterminated string: [" ^ acc ^ "\\]\n")
|
||
|
|
else
|
||
|
|
(
|
||
|
|
case String.sub (str, pos + 1) of
|
||
|
|
|
||
|
|
)
|
||
|
|
| chr =>
|
||
|
|
helpExtractString (pos + 1, str, acc ^ String.implode [chr])
|
||
|
|
|
||
|
|
fun extractString (pos, str) = helpExtractString (pos. str, "")
|
||
|
|
end
|