Utilities for lists of sigmas #
This file includes several ways of interacting with List (Sigma β)
, treated as a key-value store.
If α : Type*
and β : α → Type*
, then we regard s : Sigma β
as having key s.1 : α
and value
s.2 : β s.1
. Hence, List (Sigma β)
behaves like a key-value store.
Main Definitions #
List.keys
extracts the list of keys.List.NodupKeys
determines if the store has duplicate keys.List.lookup
/lookup_all
accesses the value(s) of a particular key.List.kreplace
replaces the first value with a given key by a given value.List.kerase
removes a value.List.kinsert
inserts a value.List.kunion
computes the union of two stores.List.kextract
returns a value with a given key and the rest of the values.
dlookup a l
is the first value in l
corresponding to the key a
,
or none
if no such element exists.
Equations
- List.dlookup a [] = none
- List.dlookup a (⟨a', b⟩ :: l) = if h : a' = a then some (Eq.recOn h b) else List.dlookup a l
Instances For
lookup_all a l
is the list of all values in l
corresponding to the key a
.
Equations
- List.lookupAll a [] = []
- List.lookupAll a (⟨a', b⟩ :: l) = if h : a' = a then Eq.recOn h b :: List.lookupAll a l else List.lookupAll a l
Instances For
Replaces the first value with key a
by b
.
Equations
- List.kreplace a b = List.lookmap fun (s : Sigma β) => if a = s.fst then some ⟨a, b⟩ else none
Instances For
Remove the first pair with the key a
.
Equations
- List.kerase a = List.eraseP fun (s : Sigma β) => decide (a = s.fst)
Instances For
Insert the pair ⟨a, b⟩
and erase the first pair with the key a
.
Equations
- List.kinsert a b l = ⟨a, b⟩ :: List.kerase a l
Instances For
Finds the first entry with a given key a
and returns its value (as an Option
because there
might be no entry with key a
) alongside with the rest of the entries.
Equations
- List.kextract a [] = (none, [])
- List.kextract a (s :: l) = if h : s.fst = a then (some (Eq.recOn h s.snd), l) else match List.kextract a l with | (b', l') => (b', s :: l')
Instances For
Remove entries with duplicate keys from l : List (Sigma β)
.
Equations
- List.dedupKeys = List.foldr (fun (x : Sigma β) => List.kinsert x.fst x.snd) []
Instances For
kunion l₁ l₂
is the append to l₁ of l₂ after, for each key in l₁, the
first matching pair in l₂ is erased.
Equations
- [].kunion x = x
- (s :: l₁).kunion x = s :: l₁.kunion (List.kerase s.fst x)