CODEWITHSUNDEEP
julia
Julia Learner
Julia Learner

Reputation: 2922

What is the code behind a number in the Julia REPL?

I asked myself the simple question in the title.

Here are the results:

julia> # Fresh 1.0.0 REPL
julia> VERSION
v"1.0.0"

julia> 2
2
julia> code_lowered(ans)
0-element Array{Union{Nothing, CodeInfo},1}

How can ans be a 0-element array to represent a 2?

Any suggestions?

Upvotes: 0

Views: 46

Answers (1)

Bogumił Kamiński
Bogumił Kamiński

Reputation: 69939

code_lowered expects a callable as a first argument. Clearly 2 is not callable so it returns array of zero IR, because there exist none for non-callable. Try code_lowered(Int) or code_lowered(sin) to see that all works fine (first is a type and second is a function - two basic kinds of callables).

It has nothing to do with ans. It just checks what ans contains, e.g.:

julia> f() = 10
f (generic function with 1 method)

julia> code_lowered(ans)
1-element Array{Core.CodeInfo,1}:
 CodeInfo(
1 1 ─     return 10                                                         │
)

julia>

Upvotes: 4

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