Generate Functions in Julia

Question

I have two functions

"This is my docstring for `add_1(x)`"
add_1(x) = x + 1

"This is my docstring for `add_2(x)`"
add_2(x) = x + 2

The code of the two functions is strikingly similar, so that in Julia there must be a clever way of automating their creation.

Side question: If these functions were generated programmatically, how would errors work out? Usually the stack trace shows a line number in the originating file, but here several functions are generated from the same line. Would it always show the same line number as well?

Answer 1

One solution would be this

["""
"This is my docstring for \`add_$i(x)\`"
add_$i(x) = x + $i
""" for i ∈ 1:3] .|> Meta.parse .|> eval

Regarding the line numbers, however, I am stuck. This is what you get by deliberately causing an error:

julia> add_3("arstoen")
ERROR: MethodError: no method matching +(::String, ::Int64)
Closest candidates are:
  +(::Any, ::Any, ::Any, ::Any...) at operators.jl:560
  +(::T, ::T) where T<:Union{Int128, Int16, Int32, Int64, Int8, UInt128, UInt16,         UInt32, UInt64, UInt8} at int.jl:87
  +(::LinearAlgebra.UniformScaling, ::Number) at /buildworker/worker/package_linux64/build/usr/share/julia/stdlib/v1.6/LinearAlgebra/src/uniformscaling.jl:145
  ...
Stacktrace:
 [1] add_3(x::String)
   @ Main ./none:2
 [2] top-level scope
   @ REPL[8]:1

Does anyone else know a way of making the stacktrace sensible?