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|
structure Stream :> STREAM = struct
type fileId = int
type fileOffset = int
type pos = fileId * fileOffset
type convPos = string * int * int option
type filesInfo = (fileId * string * string) list
exception EndOfStream
exception EndOfFile
(* unreachable *)
exception InvalidStream
exception InvalidStreamAdvance
exception LineWithoutNl
fun pos2str (pos, line, col) =
let
val % = Int.toString
in
case col of
SOME col => pos ^ ":" ^ %line ^ ":" ^ %col
| NONE => pos ^ ":" ^ %line
end
type t = {
(* stack of file ids, file offsets and file contents *)
stack: (fileId * fileOffset * string) list,
(* list of file ids, file names and file contents *)
allFiles: filesInfo
}
fun extractFilesInfo (s: t) = #allFiles s
fun calcFilePos s offset =
let
fun calc s cur offset (line, col) =
if cur = offset then
(line, col)
else
calc s (cur + 1) offset
(if String.sub (s, cur) = #"\n" then (line + 1, 1)
else (line, col + 1))
in
calc s 0 offset (1, 1)
end
fun printPos fileList (id, pos) =
let
val triple = List.find (fn (fid, _, _) => fid = id) fileList
in
case triple of
NONE => raise InvalidStream
| SOME (_, fname, contents) =>
let
val (line, col) = calcFilePos contents pos
val line = Int.toString line
val col = Int.toString col
in
print $ fname ^ ":" ^ line ^ ":" ^ col ^ ": "
end
end
fun readFile fname =
let
open TextIO
val h = openIn fname
val s = inputAll h
val () = closeIn h
in
s
end
fun getchar
({ stack = (id, off, contents) :: rest, allFiles }: t)
: (char * t) =
if off < String.size contents then
(String.sub (contents, off),
{ stack = (id, off + 1, contents) :: rest, allFiles })
else
raise EndOfFile
| getchar _ = raise EndOfStream
fun ungetc
({ stack = (id, off, contents) :: rest, allFiles }) =
if off = 0 then
raise InvalidStream
else
{ stack = (id, off - 1, contents) :: rest, allFiles }
| ungetc _ = raise InvalidStream
fun readline { stack = (fid, off, contents) :: rest, allFiles } =
let
val prevIsSlash =
off > 0 andalso String.sub (contents, off - 1) = #"\\"
open String
fun read prevIsSlash offset acc =
let
val c = sub (contents, offset)
in
if offset = size contents then
raise LineWithoutNl
else if c = #"\n" then
if prevIsSlash then
read (c = #"\\") (offset + 1) (#" " :: tl acc)
else
(implode $ rev acc, offset + 1)
else
read (c = #"\\") (offset + 1) (c :: acc)
end
val (arg, newOffset) = read prevIsSlash off []
in
(arg, { stack = (fid, newOffset, contents) :: rest, allFiles })
end
| readline _ = raise InvalidStream
fun getOffset ({ stack = (_, off, _) :: _, ... }: t) = off
| getOffset _ = raise InvalidStream
fun getPosAfterCharRead
({ stack = (id, off, _) :: _, ... }: t) = (id, off - 1)
| getPosAfterCharRead _ = raise InvalidStream
fun getPposFromPos (id, pos)
{ stack = (_, _, _) :: _, allFiles} =
let
val (fname, contents) =
case List.find (fn (fid, _, _) => fid = id) allFiles of
NONE => raise InvalidStream
| SOME (_, fname, contents) => (fname, contents)
val (line, col) = calcFilePos contents pos
in
(fname, line, SOME col)
end
| getPposFromPos _ _ = raise InvalidStream
fun getPos ({ stack = (id, off, _) :: _, ... }: t) = (id, off)
| getPos _ = raise InvalidStream
fun getSubstr startOff endOff
({ stack = (_, _, contents) :: _, ... }: t) =
String.substring (contents, startOff, endOff - startOff)
| getSubstr _ _ _ = raise InvalidStream
fun advanceToNewFile
({ stack = (_, off, contents) :: rest, allFiles }: t) =
if off = String.size contents then
{ stack = rest, allFiles }
else
raise InvalidStreamAdvance
| advanceToNewFile _ = raise InvalidStreamAdvance
fun streamInit fname =
let
val contents = readFile fname
in
{ allFiles = [(0, fname, contents)], stack = [(0, 0, contents)] }
end
fun isFirstOnLine (id, offset) (stream: t) =
case List.find (fn (fid, _, _) => id = fid) (#allFiles stream) of
NONE => raise InvalidStream
| SOME (_, _, contents) =>
let
fun returnToNL ~1 = true
| returnToNL offset =
let
val chr = String.sub (contents, offset)
in
if chr = #"\n" then
true
else if Char.isSpace chr then
returnToNL (offset - 1)
else
false
end
in
returnToNL (offset - 1)
end
end
|
