Merge pull request #23 from queryverse/unique-command

Unique command

Author: davidanthoff

NEWS.md

@@ -1,3 +1,6 @@
+# QueryOperators.jl v0.6.0 Release Notes
+* Add unique command
+
 # QueryOperators.jl v0.5.2 Release Notes
 * Various bug fixes
 * Some new features for NamedTupleUtilities

src/QueryOperators.jl

@@ -22,6 +22,7 @@ include("enumerable/enumerable_defaultifempty.jl")
 include("enumerable/enumerable_count.jl")
 include("enumerable/enumerable_take.jl")
 include("enumerable/enumerable_drop.jl")
+include("enumerable/enumerable_unique.jl")
 include("enumerable/show.jl")
 
 include("source_iterable.jl")

src/enumerable/enumerable_unique.jl

@@ -0,0 +1,49 @@
+struct EnumerableUnique{T,TKEY,S,Q<:Function} <: Enumerable
+    source::S
+    f::Q
+end
+
+function unique(source::Enumerable, f::Function, f_expr::Expr)
+    T = eltype(source)
+    S = typeof(source)
+    TKEY = Base._return_type(f, Tuple{T,})
+    return EnumerableUnique{T,TKEY,S,typeof(f)}(source, f)
+end
+
+Base.eltype(::Type{EnumerableUnique{T,TKEY,S,Q}}) where {T,TKEY,S,Q} = T
+
+function Base.iterate(iter::EnumerableUnique{T,TKEY,S,Q}) where {T,TKEY,S,Q}
+    ret = iterate(iter.source)
+    
+    ret===nothing && return nothing
+
+    observed_keys = Set{TKEY}()
+
+    first_element = ret[1]
+    source_state = ret[2]
+
+    key_first_element = iter.f(first_element)
+
+    push!(observed_keys, key_first_element)
+
+    return first_element, (observed_keys=observed_keys, source_state=source_state)
+end
+
+function Base.iterate(iter::EnumerableUnique{T,TKEY,S,Q}, state) where {T,TKEY,S,Q}
+    ret = iterate(iter.source, state.source_state)
+
+    ret===nothing && return nothing
+
+    while true
+        current_element = ret[1]
+        key_current_element=iter.f(current_element)
+        if key_current_element in state.observed_keys
+            ret = iterate(iter.source, ret[2])
+            ret===nothing && return nothing
+        else
+            push!(state.observed_keys, key_current_element)
+
+            return current_element, (observed_keys=state.observed_keys, source_state=ret[2])
+        end
+    end
+end

src/operators.jl

@@ -116,3 +116,10 @@ function drop end
 macro drop(source, n)
 	:(drop($(esc(source)), $(esc(n))))
 end
+
+function unique end
+
+macro unique(source, f)
+    q = Expr(:quote, f)
+    :(unique($(esc(source)), $(esc(f)), $(esc(q))))
+end

test/runtests.jl

@@ -149,6 +149,8 @@ a │ b │ c
 
 end
 
+include("test_enumerable_unique.jl")
+
 include("test_namedtupleutilities.jl")
 
 end

test/test_enumerable_unique.jl

@@ -0,0 +1,21 @@
+using Test
+
+@testset "unique" begin
+
+source_1 = [1,2,2,3,3,3,4]
+enum = QueryOperators.query(source_1)
+
+@test collect(QueryOperators.@unique(enum, i->i)) == [1,2,3,4]
+
+source_1 = [1,2,3,4]
+enum = QueryOperators.query(source_1)
+
+@test collect(QueryOperators.@unique(enum, i->i)) == [1,2,3,4]
+
+source_1 = [1,-1,2,3,4]
+enum = QueryOperators.query(source_1)
+
+@test collect(QueryOperators.@unique(enum, i->abs(i))) == [1,2,3,4]
+
+
+end