Is there a build-in Julia function for stripping LineNumberNode
in Expr
? especially for macrocalls:
julia> ex = :(@foo 1)
:(#= REPL[5]:1 =# @foo 1)
julia> dump(ex)
Expr
head: Symbol macrocall
args: Array{Any}((3,))
1: Symbol @foo
2: LineNumberNode
line: Int64 1
file: Symbol REPL[5]
3: Int64 1
Tried MacroTools.striplines
, but
julia> ex = :(@foo 1+1)
:(#= REPL[7]:1 =# @foo 1 + 1)
julia> MacroTools.striplines(ex) |> dump
Expr
head: Symbol macrocall
args: Array{Any}((3,))
1: Symbol @foo
2: LineNumberNode
line: Int64 1
file: Symbol REPL[7]
3: Expr
head: Symbol call
args: Array{Any}((3,))
1: Symbol +
2: Int64 1
3: Int64 1
My use-case is to compare two different exprs constructed in different files(so different line number info). My current workaround is to explicitly write Expr(:macrocall, Symbol("@foo"), nothing, :(1+1)) which is a little bit verbose.
The built-in function is Base.remove_linenums!
:
julia> ex = quote begin
x = 3
y = 2
z = 4
foo(x) = 3
end
end
quote
#= REPL[2]:1 =#
begin
#= REPL[2]:2 =#
x = 3
#= REPL[2]:3 =#
y = 2
#= REPL[2]:4 =#
z = 4
#= REPL[2]:5 =#
foo(x) = begin
#= REPL[2]:5 =#
3
end
end
end
julia> Base.remove_linenums!(ex)
quote
begin
x = 3
y = 2
z = 4
foo(x) = begin
3
end
end
end
Credit to Alex Arslan for reminding me of it.
Not built in, but MacroTools.jl has MacroTools.striplines(ex)
which removes the LineNumberNodes
from an expression.
Since your goal is to be able to compare Expr
s maybe replace LineNumberNode
s with nothing
. This allows to make comparisons and the Expr
s still work. See the example below:
julia> macro hello(world)
println("hello ",world)
end
@hello (macro with 1 method)
julia> m1 = :(@hello "world")
:(#= REPL[99]:1 =# @hello "world")
julia> m2 = :(@hello "world")
:(#= REPL[100]:1 =# @hello "world")
julia> m1 == m2
false
julia> replace!(arg -> typeof(arg) <: LineNumberNode ? nothing : arg, m1.args);
julia> replace!(arg -> typeof(arg) <: LineNumberNode ? nothing : arg, m2.args);
julia> dump(m1)
Expr
head: Symbol macrocall
args: Array{Any}((3,))
1: Symbol @hello
2: Nothing nothing
3: String "world"
julia> eval(m1)
hello world
julia> m1 == m2
true
Of course if your code is nested you will have to make the replace its elements recursively over the entire Expr
's AST.
You can consider defining the following function to achieve what you want by comparing two expressions for equality ignoring line number nodes:
function cmpexpr(ex1::Expr, ex2::Expr)
ex1.head === ex2.head || return false
length(ex1.args) === length(ex2.args) || return false
for (a1, a2) in zip(ex1.args, ex2.args)
typeof(a1) === typeof(a2) || return false
if a1 isa Expr
cmpexpr(a1, a2) || return false
elseif !(a1 isa LineNumberNode)
isequal(a1, a2) || return false
end
end
return true
end
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