The plists Module¶
Overview¶
Property lists associate values with keys, but without the overhead of a
<table>. These are generally useful for a small number of keys or
where memory usage is a concern.
This implementation allows plists to be stored in either a <list>
or a <vector>. The keys are commonly called indicators and are
typically a <symbol>. The values can be any <object>.
In memory, the plist is arranged with keys and values alternating in a single sequence:
#[key1:, 1, key2:, 2]
Conveniently, this is the same layout as a sequence of arguments when
using #rest in conjunction with keyword arguments and #all-keys
as can be seen in the example using with-keywords-removed.
Reading¶
Modifying¶
Iterating¶
Reference¶
- get-property Generic function¶
Return the value for an indicator, with a default should it not exist.
- Signature:
get-property plist indicator #key default => property
- Parameters:
plist – An instance of
<sequence>.indicator – An instance of
<object>.default (#key) – An instance of
<object>.
- Values:
property – An instance of
<object>.
- keyword-sequence Generic function¶
Returns a sequence containing the indicators in the plist.
- Signature:
keyword-sequence plist => keywords
- Parameters:
plist – An instance of
<sequence>.
- Values:
keywords – An instance of
<sequence>.
- See also:
- put-property! Statement Macro¶
Modify the plist, adding indicator with the given value.
- Macro Call:
put-property!(plist, indicator, value)
- Parameters:
plist – An instance of
<sequence>.indicator – An instance of
<object>.value – An instance of
<object>.
- Example:
put-property!(buffer-contents-properties(buffer), #"optimization-colors", #f)
- See also:
- remove-keywords Generic function¶
Returns a copy of the plist with keywords removed.
- Signature:
remove-keywords plist keywords => plist
- Parameters:
plist – An instance of
<sequence>.keywords – An instance of
<sequence>.
- Values:
plist – An instance of
<sequence>.
- See also:
- remove-property! Statement Macro¶
Modify the plist, removing indicator, returning the old value, if any.
- Macro Call:
remove-property!(plist, indicator)
- Parameters:
plist – An instance of
<sequence>.indicator – An instance of
<object>.
- Values:
value – An instance of
<object>.
- Example:
remove-property!(buffer-properties(buffer), #"project");
- See also:
- value-sequence Generic function¶
Returns a sequence containing the values in the plist.
- Signature:
value-sequence plist => values
- Parameters:
plist – An instance of
<sequence>.
- Values:
values – An instance of
<sequence>.
- See also:
- with-keywords-removed Statement Macro¶
- Macro Call:
with-keywords-removed(var = plist, keywords) body end
- Parameters:
var – A Dylan name BNF.
plist – An instance of
<sequence>.keywords – An instance of
<sequence>.body – A Dylan body BNF.
- Discussion:
Executes the body, with the keywords removed from plist and the modified plist available as var.
- Example:
define sealed method make (class == <interval-stream>, #rest initargs, #key buffer, interval, direction, #all-keys) => (stream :: <interval-stream>) ignore(direction); let (start-bp, end-bp) = values(interval-start-bp(buffer | interval), interval-end-bp(buffer | interval)); let buffer = buffer | select (interval by instance?) <buffer> => interval; otherwise => bp-buffer(start-bp); end; with-keywords-removed (initargs = initargs, #[interval:]) apply(next-method, class, start-bp: start-bp, end-bp: end-bp, buffer: buffer, initargs) end end method make;
- See also: