1 files changed, 75 insertions, 0 deletions
diff --git a/stdlib/lexing.ml b/stdlib/lexing.ml
new file mode 100644
index 000000000..07bb7b5df
--- /dev/null
+++ b/stdlib/lexing.ml
@@ -0,0 +1,75 @@
+(* The run-time library for lexers generated by camllex *)
+
+type lexbuf =
+  { refill_buff : lexbuf -> unit;
+    lex_buffer : string;
+    mutable lex_abs_pos : int;
+    mutable lex_start_pos : int;
+    mutable lex_curr_pos : int;
+    mutable lex_last_pos : int;
+    mutable lex_last_action : lexbuf -> Obj.t }
+
+let lex_aux_buffer = String.create 1024
+
+let lex_refill read_fun lexbuf =
+  let read =
+    read_fun lex_aux_buffer 1024 in
+  let n =
+    if read > 0
+    then read
+    else (String.unsafe_set lex_aux_buffer 0 '\000'; 1) in
+  String.unsafe_blit lexbuf.lex_buffer n lexbuf.lex_buffer 0 (2048 - n);
+  String.unsafe_blit lex_aux_buffer 0 lexbuf.lex_buffer (2048 - n) n;
+  lexbuf.lex_abs_pos <- lexbuf.lex_abs_pos + n;
+  lexbuf.lex_curr_pos <- lexbuf.lex_curr_pos - n;
+  lexbuf.lex_start_pos <- lexbuf.lex_start_pos - n;
+  lexbuf.lex_last_pos <- lexbuf.lex_last_pos - n;
+  if lexbuf.lex_start_pos < 0 then failwith "lexing: token too long"
+
+let dummy_action x = failwith "lexing: empty token"
+
+let from_function f =
+  { refill_buff = lex_refill f;
+    lex_buffer = String.create 2048;
+    lex_abs_pos = - 2048;
+    lex_start_pos = 2048;
+    lex_curr_pos = 2048;
+    lex_last_pos = 2048;
+    lex_last_action = dummy_action }
+
+let from_channel ic =
+  from_function (fun buf n -> input ic buf 0 n)
+
+let from_string s =
+  { refill_buff =
+      (fun lexbuf -> lexbuf.lex_curr_pos <- lexbuf.lex_curr_pos - 1);
+    lex_buffer = s ^ "\000";
+    lex_abs_pos = 0;
+    lex_start_pos = 0;
+    lex_curr_pos = 0;
+    lex_last_pos = 0;
+    lex_last_action = dummy_action }
+
+external get_next_char : lexbuf -> char = "get_next_char"
+
+let lexeme lexbuf =
+  let len = lexbuf.lex_curr_pos - lexbuf.lex_start_pos in
+  let s = String.create len in
+  String.unsafe_blit lexbuf.lex_buffer lexbuf.lex_start_pos s 0 len; s
+
+let lexeme_char lexbuf i =
+  String.get lexbuf.lex_buffer (lexbuf.lex_start_pos + i)
+
+let start_lexing lexbuf =
+  lexbuf.lex_start_pos <- lexbuf.lex_curr_pos;
+  lexbuf.lex_last_action <- dummy_action
+
+let backtrack lexbuf =
+  lexbuf.lex_curr_pos <- lexbuf.lex_last_pos;
+  Obj.magic(lexbuf.lex_last_action lexbuf)
+
+let lexeme_start lexbuf =
+  lexbuf.lex_abs_pos + lexbuf.lex_start_pos
+and lexeme_end lexbuf =
+  lexbuf.lex_abs_pos + lexbuf.lex_curr_pos
+