55 lines
1.2 KiB
Lua
55 lines
1.2 KiB
Lua
--- MultiMap, a Map which has multiple values per key.
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--
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-- Dependencies: `pl.utils`, `pl.class`, `pl.List`, `pl.Map`
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-- @classmod pl.MultiMap
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local utils = require 'pl.utils'
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local class = require 'pl.class'
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local List = require 'pl.List'
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local Map = require 'pl.Map'
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-- MultiMap is a standard MT
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local MultiMap = utils.stdmt.MultiMap
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class(Map,nil,MultiMap)
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MultiMap._name = 'MultiMap'
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function MultiMap:_init (t)
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if not t then return end
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self:update(t)
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end
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--- update a MultiMap using a table.
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-- @param t either a Multimap or a map-like table.
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-- @return the map
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function MultiMap:update (t)
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utils.assert_arg(1,t,'table')
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if Map:class_of(t) then
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for k,v in pairs(t) do
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self[k] = List()
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self[k]:append(v)
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end
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else
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for k,v in pairs(t) do
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self[k] = List(v)
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end
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end
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end
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--- add a new value to a key. Setting a nil value removes the key.
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-- @param key the key
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-- @param val the value
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-- @return the map
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function MultiMap:set (key,val)
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if val == nil then
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self[key] = nil
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else
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if not self[key] then
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self[key] = List()
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end
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self[key]:append(val)
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end
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end
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return MultiMap
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