De: Rename to Deserialize.hl

and move the file to the `src/` folder since the containing folder is
now empty.

Author: har7an

src/De/De.jl

@@ -1,4 +1,40 @@
-# De/Deser
+# De/De
+
+abstract type DeserError <: Exception end
+
+struct ParamError <: DeserError
+    key::Any
+end
+
+function Base.show(io::IO, e::ParamError)
+    return print(
+        io,
+        "ParamError: parameter '$(e.key)' was not passed or has the value 'nothing'",
+    )
+end
+
+struct TagError <: DeserError
+    tag::Any
+end
+
+function Base.show(io::IO, e::TagError)
+    return print(io, "TagError: tag for method '$(e.tag)' is not declared")
+end
+
+struct WrongType <: DeserError
+    maintype::DataType
+    key::Any
+    value::Any
+    from_type::Any
+    to_type::Any
+end
+
+function Base.show(io::IO, e::WrongType)
+    return print(
+        io,
+        "WrongType: for '$(e.maintype)' value '$(e.value)' has wrong type '$(e.key)::$(e.from_type)', must be '$(e.key)::$(e.to_type)'",
+    )
+end
 
 """
     ClassType
@@ -543,3 +579,54 @@ function deser(::CustomType, ::Type{D}, data::N)::D where {D<:Any,N<:NamedTuple}
 
     return D(vals...)
 end
+
+function tag(::Type{T}, ::Val{x}) where {T,x}
+    return throw(TagError(x))
+end
+
+tag(::Type{T}, ::Nothing) where {T} = T
+
+(tag_key(::Type)::Nothing) = nothing
+(tag_val(::Type{T}, ::Nothing, v)::Nothing) where {T} = nothing
+
+function tag_val(::Type{T}, k, v) where {T}
+    try
+        Val(Symbol(v[k]))
+    catch
+        throw(ParamError(k))
+    end
+end
+
+deser_type(::Type{T}, x) where {T} = tag(T, tag_val(T, tag_key(T), x))
+deser_value(::Type{T}, x) where {T} = x
+
+"""
+    Serde.to_deser(::Type{T}, x) -> T
+
+Creates a new object of type `T` with values corresponding to the key-value pairs of the dictionary `x`.
+
+## Examples
+```julia-repl
+julia> struct Info
+           id::Int64
+           salary::Int64
+       end
+
+julia> struct Person
+           name::String
+           age::Int64
+           info::Info
+       end
+
+julia> info_data = Dict("id" => 12, "salary" => 2500);
+
+julia> person_data = Dict("name" => "Michael", "age" => 25, "info" => info_data);
+
+julia> Serde.to_deser(Person, person_data)
+Person("Michael", 25, Info(12, 2500))
+```
+"""
+to_deser(::Type{T}, x) where {T} = deser(deser_type(T, x), deser_value(T, x))
+
+to_deser(::Type{Nothing}, x) = nothing
+to_deser(::Type{Missing}, x) = missing

src/De/Deser.jl src/Deserialize.jlsrc/De/Deser.jl renamed to src/Deserialize.jl

@@ -36,8 +36,8 @@ export @serde,
     to_flatten
 
 include("Utl/Utl.jl")
-include("De/De.jl")
 include("Serialize.jl")
+include("Deserialize.jl")
 
 include("API.jl")
 using .API