package bos
Library
Module
Module type
Parameter
Class
Class type
include module type of struct include Bos.Pat end
Named string patterns.
Named string patterns are strings with variables of the form "$(VAR)"
where VAR
is any (possibly empty) sequence of bytes except ')'
or ','
. In a named string pattern a "$"
literal must be escaped by "$$"
.
Named string patterns can be used to format strings or to match data.
Patterns
type t = Bos.Pat.t
The type for patterns.
val v : string -> t
v s
is a pattern from the string s
.
val empty : t
empty
is an empty pattern.
val dom : t -> Astring.String.Set.t
dom p
is the set of variables in p
.
compare p p'
is Pervasives.compare
p p'
.
val of_string : string -> (t, [> Rresult.R.msg ]) Result.result
of_string s
parses s
according to the pattern syntax (i.e. a literal '$'
must be represented by "$$"
in s
).
val to_string : t -> string
to_string p
converts p
to a string according to the pattern syntax (i.e. a literal '$'
will be represented by "$$"
).
val pp : Format.formatter -> t -> unit
pp ppf p
prints p
on ppf
according to the pattern syntax.
val dump : Format.formatter -> t -> unit
dump ppf p
prints p
as a syntactically valid OCaml string on ppf
.
Substitution
Note. Substitution replaces variables with data, i.e. strings. It cannot substitute variables with variables.
type defs = string Astring.String.Map.t
Type type for variable definitions. Maps pattern variable names to strings.
subst ~undef defs p
tries to substitute variables in p
by their value. First a value is looked up in defs
and if not found in undef
. undef
defaults to (fun _ -> None)
.
format ~undef defs p
substitutes all variables in p
with data. First a value is looked up in defs
and if not found in undef
(defaults to fun _ -> ""
). The resulting string is not in pattern syntax (i.e. a literal '$'
is represented by '$'
in the result).
Matching
Pattern variables greedily match from zero to more bytes from left to right. This is .*
in regexp speak.
val matches : t -> string -> bool
matches p s
is true
iff the string s
matches p
. Here are a few examples:
matches (v "$(mod).mli") "string.mli"
istrue
.matches (v "$(mod).mli") "string.mli "
isfalse
.matches (v "$(mod).mli") ".mli"
istrue
.matches (v "$(mod).$(suff)") "string.mli"
istrue
.matches (v "$(mod).$(suff)") "string.mli "
istrue
.
query ~init p s
is like matches
except that a matching string returns a map from each pattern variable to its matched part in the string (mappings are added to init
, defaults to String.Map.empty
) or None
if s
doesn't match p
. If a variable appears more than once in pat
the first match is returned in the map.