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(* Printing a location in the source program *)
(* inspired from the source of the Caml Light 0.73 compiler *)
open Lexing
open Parsing
open Format
(* two important global variables: [input_name] and [input_chan] *)
type location =
Loc of position (* Position of the first character *)
* position (* Position of the next character following the last one *)
let input_name = ref "" (* Input file name. *)
let input_chan = ref stdin (* The channel opened on the input. *)
let initialize iname ic =
input_name := iname;
input_chan := ic
let no_location = Loc (dummy_pos, dummy_pos)
let error_prompt = ">"
(** Prints [n] times char [c] on [oc]. *)
let prints_n_chars ff n c = for i = 1 to n do pp_print_char ff c done
(** Prints out to [oc] a line designed to be printed under [line] from file [ic]
underlining from char [first] to char [last] with char [ch].
[line] is the index of the first char of line. *)
let underline_line ic ff ch line first last =
let c = ref ' '
and f = ref first
and l = ref (last-first) in
( try
seek_in ic line;
pp_print_string ff error_prompt;
while c := input_char ic; !c != '\n' do
if !f > 0 then begin
f := !f - 1;
pp_print_char ff (if !c == '\t' then !c else ' ')
end
else if !l > 0 then begin
l := !l - 1;
pp_print_char ff (if !c == '\t' then !c else ch)
end
else ()
done
with End_of_file ->
if !f = 0 && !l > 0 then prints_n_chars ff 5 ch )
let copy_lines nl ic ff prompt =
for i = 1 to nl do
pp_print_string ff prompt;
(try pp_print_string ff (input_line ic)
with End_of_file -> pp_print_string ff "<EOF>");
fprintf ff "@\n"
done
let copy_chunk p1 p2 ic ff =
try for i = p1 to p2 - 1 do pp_print_char ff (input_char ic) done
with End_of_file -> pp_print_string ff "<EOF>"
let skip_lines n ic =
try for i = 1 to n do
let _ = input_line ic in ()
done
with End_of_file -> ()
let print_location ff (Loc(p1,p2)) =
let n1 = p1.pos_cnum - p1.pos_bol in (* character number *)
let n2 = p2.pos_cnum - p2.pos_bol in
let np1 = p1.pos_cnum in (* character position *)
let np2 = p2.pos_cnum in
let l1 = p1.pos_lnum in (* line number *)
let l2 = p2.pos_lnum in
let lp1 = p1.pos_bol in (* line position *)
let lp2 = p2.pos_bol in
let f1 = p1.pos_fname in (* file name *)
let f2 = p2.pos_fname in
if f1 != f2 then (* Strange case *)
fprintf ff
"File \"%s\" line %d, character %d, to file \"%s\" line %d, character %d@."
f1 l1 n1 f2 l2 n2
else begin (* Same file *)
if l2 > l1 then
fprintf ff
"File \"%s\", line %d-%d, characters %d-%d:@\n" f1 l1 l2 n1 n2
else
fprintf ff "File \"%s\", line %d, characters %d-%d:@\n" f1 l1 n1 n2;
(* Output source code *)
try
let ic = open_in f1 in
if l1 == l2 then (
(* Only one line : copy full line and underline *)
seek_in ic lp1;
copy_lines 1 ic ff ">";
underline_line ic ff '^' lp1 n1 n2 )
else (
underline_line ic ff '.' lp1 0 n1; (* dots until n1 *)
seek_in ic np1;
(* copy the end of the line l1 after the dots *)
copy_lines 1 ic ff "";
if l2 - l1 <= 8 then
(* copy the 6 or less middle lines *)
copy_lines (l2-l1-1) ic ff ">"
else (
(* sum up the middle lines to 6 *)
copy_lines 3 ic ff ">";
fprintf ff "..........@\n";
skip_lines (l2-l1-7) ic; (* skip middle lines *)
copy_lines 3 ic ff ">"
);
fprintf ff ">";
copy_chunk lp2 np2 ic ff; (* copy interesting begining of l2 *)
)
with Sys_error _ -> ();
end;
fprintf ff "@."
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