Moved qparser and syntax in the library folder

1 files changed, 212 insertions, 0 deletions

diff --git a/lib/qparser/lexer.ml b/lib/qparser/lexer.ml
new file mode 100644
index 0000000..c643577
--- /dev/null
+++ b/lib/qparser/lexer.ml
@@ -0,0 +1,212 @@
+(** 
+    Lexer using sedlex
+ *)
+
+open Tokens
+
+exception UnclosedQuote of { content : string; line : int }
+exception LexError of Lexing.position * string
+exception EOF
+
+let pp_pos out { Lexing.pos_lnum; pos_cnum; pos_bol; _ } =
+  Format.fprintf out "line %d:%d" pos_lnum (pos_cnum - pos_bol)
+
+(* Extract the location name from the pattern *)
+let location_name = Str.regexp {|.* \(.*\)|}
+
+let build_ident buffer =
+  let id = Lexbuf.content buffer |> String.uppercase_ascii in
+  try
+    let value = Hashtbl.find Idents.keyword_table id in
+    let _ =
+      match value with IF | ELIF -> Lexbuf.incr_level buffer | _ -> ()
+    in
+    value
+  with Not_found -> IDENT id
+
+let wait_balance : (Buffer.t -> Lexbuf.t -> 'a) -> Lexbuf.t -> 'a =
+ fun rule lexbuf ->
+  let _, position = Lexbuf.positions lexbuf in
+  Lexbuf.set_start_position lexbuf position;
+
+  try[@warning "-52"]
+    let token = rule (Buffer.create 256) lexbuf in
+    token
+  with Failure "lexing: empty token" ->
+    let position, _ = Lexbuf.positions lexbuf in
+    let line = position.Lexing.pos_lnum and content = Lexbuf.content lexbuf in
+    (raise (UnclosedQuote { line; content }) [@warning "+52"])
+
+let space = [%sedlex.regexp? ' ' | '\t']
+let eol = [%sedlex.regexp? '\r' | '\n' | "\r\n"]
+let coma = [%sedlex.regexp? ',']
+let digit = [%sedlex.regexp? '0' .. '9']
+let letters = [%sedlex.regexp? 'a' .. 'z' | 'A' .. 'Z' | '_']
+let spaces = [%sedlex.regexp? Plus space]
+let ident = [%sedlex.regexp? ('$' | letters), Star (digit | letters)]
+let location_ident = [%sedlex.regexp? letters | digit]
+let location_prefix = [%sedlex.regexp? '!' | '$' | '#' | '^']
+let location = [%sedlex.regexp? Opt location_prefix, Plus location_ident]
+
+let rec read_long_string level buf buffer =
+  let lexbuf = Lexbuf.buffer buffer in
+  match%sedlex lexbuf with
+  | '{' ->
+      Buffer.add_string buf (Sedlexing.Utf8.lexeme lexbuf);
+      read_long_string (level + 1) buf buffer
+  | '}' -> (
+      match level with
+      | 0 -> Buffer.contents buf
+      | _ ->
+          Buffer.add_string buf (Sedlexing.Utf8.lexeme lexbuf);
+          read_long_string (level - 1) buf buffer)
+  | eol ->
+      Buffer.add_string buf (Lexbuf.content buffer);
+      read_long_string level buf buffer
+  | any ->
+      Buffer.add_string buf (Lexbuf.content buffer);
+      read_long_string level buf buffer
+  | _ -> raise Not_found
+
+let rec read_dquoted_string buf buffer =
+  let lexbuf = Lexbuf.buffer buffer in
+  match%sedlex lexbuf with
+  | "\"\"" ->
+      Buffer.add_char buf '"';
+      read_dquoted_string buf buffer
+  | '"' -> Buffer.contents buf
+  | any ->
+      Buffer.add_string buf (Sedlexing.Utf8.lexeme lexbuf);
+      read_dquoted_string buf buffer
+  | _ -> raise Not_found
+
+let rec read_quoted_string buf buffer =
+  let lexbuf = Lexbuf.buffer buffer in
+  match%sedlex lexbuf with
+  | "''" ->
+      Buffer.add_char buf '\'';
+      read_quoted_string buf buffer
+  | '\'' -> Buffer.contents buf
+  | eol ->
+      Buffer.add_string buf (Lexbuf.content buffer);
+      read_quoted_string buf buffer
+  | any ->
+      Buffer.add_string buf (Lexbuf.content buffer);
+      read_quoted_string buf buffer
+  | _ -> raise Not_found
+
+let rec skip_comment buffer =
+  let lexbuf = Lexbuf.buffer buffer in
+  match%sedlex lexbuf with
+  | '{' ->
+      let _ = wait_balance (read_long_string 0) buffer in
+      skip_comment buffer
+  | '\'' ->
+      let _ = wait_balance read_quoted_string buffer in
+      skip_comment buffer
+  | '"' ->
+      let _ = wait_balance read_dquoted_string buffer in
+      skip_comment buffer
+  | eol ->
+      (* Ugly hack used in order to put the eol in the front of the next
+         parsing. *)
+      Sedlexing.rollback lexbuf;
+      COMMENT
+  | any -> skip_comment buffer
+  | _ -> raise Not_found
+
+(** Main lexer *)
+let rec token : Lexbuf.t -> token =
+ fun buffer ->
+  let lexbuf = Lexbuf.buffer buffer in
+  match%sedlex lexbuf with
+  | 0Xfeff ->
+      (* Ignore the BOM *)
+      token buffer
+  | '#', Star space, location ->
+      (* Extract the location name *)
+      let ident = Lexbuf.content buffer in
+      let () =
+        match Str.string_match location_name ident 0 with
+        | false -> ()
+        | true -> Sedlexing.set_filename lexbuf (Str.matched_group 1 ident)
+      in
+
+      (* Restart the line number (new location here) *)
+      Lexbuf.start buffer;
+
+      LOCATION_START ident
+  | '-', Plus '-', Star (Sub (any, ('\r' | '\n'))) ->
+      Lexbuf.reset_level buffer;
+      LOCATION_END
+  | Plus digit -> INTEGER (Lexbuf.content buffer)
+  | '+' -> PLUS
+  | '-' -> MINUS
+  | "+=" -> INCR
+  | "-=" -> DECR
+  | "*=" -> MULT_EQUAL
+  | '/' -> DIV
+  | '*' -> STAR
+  | ':' ->
+      (* We are leaving the block, the comment will be handled again *)
+      Lexbuf.decr_level buffer;
+
+      COLUMN
+  | '[' -> L_BRACKET
+  | ']' -> R_BRACKET
+  | '(' ->
+      Lexbuf.incr_level buffer;
+      L_PAREN
+  | ')' ->
+      Lexbuf.decr_level buffer;
+      R_PAREN
+  | '<' -> LT
+  | '>' -> GT
+  | coma -> COMA
+  | '=' ->
+      Lexbuf.incr_level buffer;
+      EQUAL
+  | ident -> build_ident buffer
+  | eol ->
+      Lexbuf.reset_level buffer;
+      EOL
+  | '&' ->
+      Lexbuf.reset_level buffer;
+      AMPERSAND
+  | '!' -> if Lexbuf.level buffer > 0 then EXCLAMATION else skip_comment buffer
+  | spaces -> token buffer
+  | '\'' -> LITERAL (wait_balance read_quoted_string buffer)
+  | '"' -> LITERAL (wait_balance read_dquoted_string buffer)
+  | '{' -> LITERAL (wait_balance (read_long_string 0) buffer)
+  | eof -> raise EOF
+  | _ ->
+      let position = fst @@ Sedlexing.lexing_positions lexbuf in
+      let tok = Lexbuf.content buffer in
+
+      let msg =
+        Format.asprintf "Unexpected character %S at %a" tok pp_pos position
+      in
+
+      raise @@ LexError (position, msg)
+
+let rec discard buffer =
+  let lexbuf = Lexbuf.buffer buffer in
+  match%sedlex lexbuf with
+  | '\'' ->
+      ignore (wait_balance read_quoted_string buffer);
+      discard buffer
+  | '"' ->
+      ignore (wait_balance read_dquoted_string buffer);
+      discard buffer
+  | '{' ->
+      ignore (wait_balance (read_long_string 0) buffer);
+      discard buffer
+  | eof -> raise EOF
+  | '-', Plus '-', Star (Sub (any, ('\r' | '\n'))) ->
+      Lexbuf.reset_level buffer;
+      ()
+  | '!' ->
+      ignore @@ skip_comment buffer;
+      discard buffer
+  | any -> discard buffer
+  | _ -> raise EOF