(** Configuration repository for HELM applications.
*
- * key ::= path
- * path ::= component ( '.' component )*
- * component ::= ( alpha | num | '_' )+
+ * ++ Keys format ++
*
- * Suggested usage <application>.<setting>:
- * e.g. gTopLevel.prooffile, http_getter.port, ...
+ * key ::= path
+ * path ::= component ( '.' component )*
+ * component ::= ( lowercase_alpha | num | '_' )+
+ * # with the only exception that sequences of '_' longer than 1 aren't valid
+ * # components
*
- * Configuration file example:
+ * Suggested usage <application>.<setting>:
+ * e.g. gTopLevel.prooffile, http_getter.port, ...
+ *
+ * ++ Configuration file example ++
*
* gTopLevel.prooffile = "/home/zack/prooffile"
* http_getter.port = "58080"
+ *
+ * ++ Environment variable override ++
+ *
+ * each key has an associated environment variable name. At runtime (i.e. when
+ * "get" requests are performed) a variable with this name will be looked for,
+ * if it's defined it will override the value present (or absent) in the
+ * registry.
+ * Environment variables are _not_ considered when saving the configuration to
+ * a configuration file (via "save_to" function below) .
+ *
+ * Mapping between keys and environment variables is as follows:
+ * - the whole key is uppercased
+ * - each "." is converted to "__"
+ * E.g.: my.foo_ish.application -> MY__FOO_ISH__APPLICATION
+ *
+ * ++ Variable interpolation ++
+ *
+ * Interpolation is supported with the following syntax:
+ *
+ * foo.bar = "quux"
+ * foo.baz = $(foo.bar)/baz
*)
(** raised when a looked up key can't be found
* @param key looked up key *)
exception Key_not_found of string
+ (** raised when a cyclic definitions is found, e.g. after
+ * Helm_registry.set "a" "$b"
+ * Helm_registry.set "b" "$a"
+ * @param msg brief description of the definition cycle *)
+exception Cyclic_definition of string
+
(** raised when a looked up key doesn't have the required type
* @param expected_type
* @param value
(** raised when an error is encountered while parsing a configuration file
* @param fname file name
- * @param lno line number *)
-exception Parse_error of string * int
+ * @param line line number
+ * @param col column number
+ * @param msg error description
+ *)
+exception Parse_error of string * int * int * string
(** raised when a given <key,value> pair fails validity test(s)
* @param pair <key,value> pair
* Using the functions below this module could be used as a repository of
* key/value pairs *)
+ (** lookup key in registry with environment variable override *)
val get: string -> string
val set: key:string -> value:string -> unit
+ (** remove a key from the current environment, next get over this key will
+ * raise Key_not_found until the key will be redefined *)
+val unset: string -> unit
+
(** {2 Typed interface}
* Three basic types are supported: strings, int and strings list. Strings
* correspond literally to what is written inside double quotes; int to the
* parsing of an integer number from ; strings list to the splitting at blanks
* of it (heading and trailing blanks are removed before splitting) *)
-val get_int: string -> int
-val get_float: string -> float
-val get_string_list: string -> string list
+val get_string: string -> string (* alias for bare "get" above *)
+val get_int: string -> int
+val get_float: string -> float
+val get_bool: string -> bool
+val get_string_list: string -> string list
+
+ (* alias for bare "set" above *)
+val set_string: key:string -> value:string -> unit
+val set_int: key:string -> value:int -> unit
+val set_float: key:string -> value:float -> unit
+val set_bool: key:string -> value:bool -> unit
+val set_string_list: key:string -> value:string list -> unit
+
+(** {3 Optional values interface}
+ * Functions below took as first argument respectively a "getter" and a "setter"
+ * function. A getter is one of the get_* function above, a setter is one of the
+ * set_* function above. Returned value is a get (set) function typed as the
+ * given getter (setter) whith optional values. None is returned for missing
+ * keys and None can be assigned to a key removing it from the registry.
+ *)
-val set_int: key:string -> value:int -> unit
-val set_float: key:string -> value:float -> unit
-val set_string_list: key:string -> value:string list -> unit
+val get_opt:
+ (string -> 'a) (* getter *) ->
+ string -> 'a option
+val set_opt:
+ (key:string -> value:'a -> unit) (* setter *) ->
+ key:string -> value:'a option -> unit
(** {2 Validators}
* Each key may have zero or more associated validators, that are predicates
* Validators aren't saved. load_from/save_to sequences don't preserve comments
*)
- (** @param fname file to which save current configuration *)
+ (** @param fname file to which save current configuration
+ * If xmllint is available then it will be used for pretty printing fname,
+ * otherwise fname will be in the usual pxp ugly format *)
val save_to: string -> unit
- (** @param fname file from which load new configuration *)
-val load_from: string -> unit
+ (** @param fname file from which load new configuration. If it's an absolute
+ * file name "path" argument is ignored.
+ * Otherwise given file name is looked up in each directory member of the
+ * given path. Each matching file is loaded overriding previous settings. If
+ * no path is given a default path composed of just the current working
+ * directory is used.
+ *)
+val load_from: ?path:string list -> string -> unit
-(*
(* DEBUGGING *)
-val dump: unit -> unit
-*)
+(* val dump: unit -> unit *)
projects / helm.git / blobdiff