How can I programmatically access DocStrings? - julia

Question

I am writing a macro, that takes a function name,
and declares a couple of other version of the function.
I want to give these variations the same doc string as the original method,
with perhaps a few changes.
To do this, I need to retrieve the docstring for the orginal method.
So what I am looking for is a function:
get_docstring(functionname::Symbol, argtypes)::String
So that I could do:
julia> s=get_docstring(:values,(Associative,)) and then s would be set to:
s="""
values(a::Associative)
Return an iterator over all values in a collection.
`collect(values(d))` returns an array of values.
```jldoctest
julia> a = Dict('a'=>2, 'b'=>3)
Dict{Char,Int64} with 2 entries:
'b' => 3
'a' => 2
julia> collect(values(a))
2-element Array{Int64,1}:
3
2
```
"""

Answer 1

You can use the #doc macro, but instead of a string, it returns a markdown object:
julia> #doc "foo int" ->
foo(x::Int) = x
foo
julia> #doc "foo float" ->
foo(x::Float64) = x
foo
julia> #doc "foo sym" ->
foo(x::Symbol) = x
foo
julia> #doc "foo x, y" ->
function foo(x, y) x, y end
foo
julia> #doc foo
foo int
foo float
foo sym
foo x, y
julia> typeof(ans)
Base.Markdown.MD
julia> #doc foo(::Int)
foo int
julia> #doc foo(::Float64)
foo float
julia> #doc foo(::Symbol)
foo sym
julia> md = #doc foo(::Any, ::Any)
foo x, y
julia> md.content
1-element Array{Any,1}:
foo x, y
julia> md.content[1]
foo x, y
julia> md.content[1].content
1-element Array{Any,1}:
Base.Markdown.Paragraph(Any["foo x, y"])
julia> md.meta
Dict{Any,Any} with 3 entries:
:typesig => Tuple{Any,Any}
:results => Base.Docs.DocStr[Base.Docs.DocStr(svec("foo x, y"),foo x, y…
:binding => foo
julia>