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|
(* Parsing configuration files *)
type value =
| Bool of bool ref
| String of string ref
| Int of int ref
| Float of float ref
| Regexp of Str.regexp ref
| OptBool of bool option ref
| OptString of string option ref
| OptInt of int option ref
| OptFloat of float option ref
| OptRegexp of Str.regexp option ref
exception Error of string
let re_bool_yes = Str.regexp_case_fold "\\(on\\|yes\\|true\\|1\\)[ \t\r]*$"
let re_bool_no = Str.regexp_case_fold "\\(off\\|no\\|false\\|0\\)[ \t\r]*$"
let parse_bool data =
if Str.string_match re_bool_yes data 0 then true
else if Str.string_match re_bool_no data 0 then false
else raise (Error "invalid boolean value")
let trim_spaces s =
let i = ref (String.length s - 1) in
while !i >= 0 && (let c = s.[!i] in c = ' ' || c = '\t' || c = '\r')
do decr i done;
String.sub s 0 (!i + 1)
let parse_string data =
try
Scanf.sscanf data "%S" (fun s -> s)
with Scanf.Scan_failure _ ->
trim_spaces data
let parse_int data =
try
Scanf.sscanf data "%i" (fun n -> n)
with Scanf.Scan_failure _ | Failure _ ->
raise (Error ("invalid integer value"))
let parse_float data =
try
Scanf.sscanf data "%f" (fun n -> n)
with Scanf.Scan_failure _ | Failure _ ->
raise (Error ("invalid floating-point value"))
let parse_regexp data =
try
Str.regexp_case_fold (trim_spaces data)
with Failure msg ->
raise (Error ("invalid regular expression: " ^ msg))
let parse_data valuedesc data =
match valuedesc with
| Bool r -> r := parse_bool data
| String r -> r := parse_string data
| Int r -> r := parse_int data
| Float r -> r := parse_float data
| Regexp r -> r := parse_regexp data
| OptBool r -> r := Some(parse_bool data)
| OptString r -> r := Some(parse_string data)
| OptInt r -> r := Some(parse_int data)
| OptFloat r -> r := Some(parse_float data)
| OptRegexp r -> r := Some(parse_regexp data)
let re_line =
Str.regexp "[ \t]*\\([A-Za-z][A-Za-z0-9_]*\\)[ \t]*=[ \t]*\\(.*\\)"
let re_skip =
Str.regexp "#\\|[ \t\r]*$"
let parse_line opts s =
if Str.string_match re_line s 0 then begin
let key = Str.matched_group 1 s and data = Str.matched_group 2 s in
try
parse_data (List.assoc key opts) data
with Not_found ->
raise (Error ("unknown variable " ^ key))
end
else if not (Str.string_match re_skip s 0) then
raise (Error "ill-formed line")
let parse opts filename =
let ic = open_in filename in
let lineno = ref 1 in
let errors = ref [] in
begin try
while true do
let s = input_line ic in
begin try
parse_line opts s
with Error msg ->
errors := (!lineno, msg) :: !errors
end;
incr lineno
done
with End_of_file ->
close_in ic
end;
!errors
|
