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1
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struct EnumerableGather{T,S,F,I,A} <: Enumerable
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2
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23
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source::S
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3
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fields::F
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4
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indexFields::I
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5
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savedFields::A
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6
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key::Symbol
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7
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value::Symbol
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8
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end
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9
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10
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struct Not{T}
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11
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val::T
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12
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end
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13
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14
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function gather(source::Enumerable, args...; key::Symbol = :key, value::Symbol = :value)
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15
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23
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fields = fieldnames(eltype(source))
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16
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23
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if length(args) > 0
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17
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18
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indexFields_vector = Vector{Symbol}(undef, 0)
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18
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firstArg = true
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19
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23
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for arg in args
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20
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5
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if typeof(arg) == Symbol
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21
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18
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push!(indexFields_vector, arg)
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22
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0
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else typeof(arg) == Not{Symbol}
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23
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0
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if firstArg
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24
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0
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indexFields_vector = [a for a in fields if a != arg.val]
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25
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else
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26
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0
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indexFields_vector = [a for a in indexFields_vector if a != arg.val]
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27
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end
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28
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end
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29
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23
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firstArg = false
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30
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end
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31
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23
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indexFields = tuple(indexFields_vector...)
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32
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else
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33
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23
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indexFields = fields
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34
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end
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35
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36
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23
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savedFields = (n for n in fields if !(n in indexFields)) # fields that are not in `indexFields`
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37
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23
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savedFieldsType = (fieldtype(eltype(source), savedField) for savedField in savedFields)
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38
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39
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23
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valueTypes = (fieldtype(eltype(source), indexField) for indexField in indexFields)
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40
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23
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valueType = reduce(promote_type, valueTypes)
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41
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42
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23
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T = NamedTuple{(savedFields..., key, value), Tuple{savedFieldsType..., Symbol, valueType}}
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43
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23
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return EnumerableGather{T, typeof(source), typeof(fields), typeof(indexFields), typeof(savedFields)}(source,
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44
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fields, indexFields, savedFields, key, value)
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45
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end
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46
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47
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function Base.iterate(iter::EnumerableGather{T, S, F, I, A}) where {T, S, F, I, A}
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48
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23
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source_iterate = iterate(iter.source)
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49
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23
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if source_iterate == nothing || length(iter.indexFields) == 0
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50
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0
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return nothing
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51
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end
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52
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18
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key = iter.indexFields[1]
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53
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23
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current_source_row = source_iterate[1]
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54
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18
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value = current_source_row[key]
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55
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23
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return (T((Base.map(n->current_source_row[n], iter.savedFields)..., key, value)),
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56
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(current_source_row=current_source_row, source_state=source_iterate[2], current_index_field_index=1))
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57
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end
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58
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59
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function Base.iterate(iter::EnumerableGather{T, S, F, I, A}, state) where {T, S, F, I, A}
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60
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23
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current_index_field_index = state.current_index_field_index + 1
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61
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23
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if current_index_field_index > length(iter.indexFields)
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62
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18
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source_iterate = iterate(iter.source, state.source_state)
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63
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23
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if source_iterate == nothing || length(iter.indexFields) == 0
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64
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23
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return nothing
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65
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end
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66
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current_index_field_index = 1
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67
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23
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source_state = source_iterate[2]
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68
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23
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current_source_row = source_iterate[1]
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69
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else
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70
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18
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source_state = state.source_state
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71
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23
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current_source_row = state.current_source_row
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72
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end
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73
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23
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key = iter.indexFields[current_index_field_index]
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74
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23
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value = current_source_row[key]
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75
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23
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return (T((Base.map(n->current_source_row[n], iter.savedFields)..., key, value)),
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76
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(current_source_row=current_source_row, source_state=source_state, current_index_field_index=current_index_field_index))
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77
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end
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78
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79
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function Base.eltype(iter::EnumerableGather{T, S, F, I, A}) where {T, S, F, I, A}
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80
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0
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return T
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81
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end
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davidanthoff