Thanks Ismael,
That helps. I (erroneously) kind of expected that one version would not update
the outer variable. But that can be achieved with ‘local’ as in \doteq.
Regards,
Rob
julia> :foo ≔ 42;
julia> :bar ≔ "some bar";
julia> # \coloneq
julia> macro ≔(v, b)
e = Expr(:global, v)
:($e; $(esc(v)) = $(esc(b)))
end
@≔ (macro with 1 method)
julia> # \doteq
julia> macro ≐(v, b)
:(local $(esc(v)) = $(esc(b)))
end
@≐ (macro with 1 method)
julia> @show foo
foo = 42
42
julia> @≔ foo :FOO
:FOO
julia> @show foo
foo = :FOO
:FOO
julia> @show bar
bar = "some bar"
"some bar"
julia> @show v = @≐ bar "other bar"
v = @≐(bar,"other bar") = "other bar"
"other bar"
julia> @show bar
bar = "some bar"
"some bar"
> On Jan 6, 2016, at 15:27, Ismael VC <[email protected]> wrote:
>
> Please ignore this part:
>
> julia> macro ≔(v, b)
> e = Expr(:global, v)
> :(global $e; $(esc(v)) = $(esc(b)))
> As you can see even the end keyword is missing, so it would have made an
> incomplete input error.
>
> It was a mistake on my part I pasted an incomplete part of a prior version of
> the macro of when I was testing it sorry for the confusion.
>
> Even when you added the end keyword yourself, you can see that the second
> line says e = Expr(:global, v) and then the third says: :(global $e;
> $(esc(v)) = $(esc(b))), so global is repeating two times, the message ERROR:
> syntax: invalid syntax in "global" declaration is because this duplication,
> is like trying to type:
>
> julia> x = 5
> 5
>
> julia> let
> global global x # ooops!
> end
> ERROR: syntax: invalid syntax in "global" declaration
> in eval at boot.jl:263
> You can see that before redefining the macro it works
>
> just as expected.
>
>
> Ismael Venegas Castelló
> Data Analyst
> Cel. 044 55 6434 0229
> [email protected] <mailto:[email protected]>
> Cerro San Francisco 357, C.P. 04200
> Campestre Churubusco, Coyoacán
> Ciudad de México
>
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>
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> 2016-01-06 16:55 GMT-06:00 Rob J. Goedman <[email protected]
> <mailto:[email protected]>>:
> Hi Ismael,
>
> Just trying to learn from this thread, on both Julia 0.4.2 and 0.5 I get an
> error in the 2nd version of the macro:
>
> julia> ≔(var, block) = @eval $var = $block
> ≔ (generic function with 1 method)
>
> julia>
>
> julia> @show :foo ≔ "some foo"; foo
> :foo ≔ "some foo" = "some foo"
> "some foo"
>
> julia> @show :foo ≔ 42; foo
> :foo ≔ 42 = 42
> 42
>
> julia>
>
> julia> macro ≔(v, b)
> e = Expr(:global, v)
> :($e; $(esc(v)) = $(esc(b)))
> end
> @≔ (macro with 1 method)
>
> julia>
>
> julia> @≔ foo :FOOL
> :FOOL
>
> julia>
>
> julia> @≔ fooled :FOOLED; fooled
> :FOOLED
>
> julia>
>
> julia> macro ≔(v, b)
> e = Expr(:global, v)
> :(global $e; $(esc(v)) = $(esc(b)))
> end
> @≔ (macro with 1 method)
>
> julia>
>
> julia> @≔ bar "some bar"; bar
> ERROR: syntax: invalid syntax in "global" declaration
> in eval at ./boot.jl:265
>
> julia>
>
> julia> @≔ bar 19; bar
> ERROR: syntax: invalid syntax in "global" declaration
> in eval at ./boot.jl:265
>
> julia>
>
> julia> versioninfo()
> Julia Version 0.5.0-dev+2021
> Commit bc1c18e (2016-01-06 17:45 UTC)
> Platform Info:
> System: Darwin (x86_64-apple-darwin15.3.0)
> CPU: Intel(R) Core(TM) i7-4980HQ CPU @ 2.80GHz
> WORD_SIZE: 64
> BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
> LAPACK: libopenblas64_
> LIBM: libopenlibm
> LLVM: libLLVM-3.3
>
> In addition to the ‘end’ line, is something else needed to make exporting to
> the global environment work?
>
> Regards,
> Rob
>
>
>> On Jan 5, 2016, at 03:53, Ismael Venegas Castelló <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> You could use another similar operator like \coloneq:
>>
>> julia> ≔(var, block) = @eval $var = $block
>> ≔ (generic function with 1 method)
>>
>> julia> @show :foo ≔ "some foo"; foo
>> :foo ≔ "some foo" = "some foo"
>> "some foo"
>>
>> julia> @show :foo ≔ 42; foo
>> :foo ≔ 42 = 42
>> 42
>>
>> julia> macro ≔(v, b)
>> e = Expr(:global, v)
>> :($e; $(esc(v)) = $(esc(b)))
>> end
>>
>> julia> @≔ foo :FOO
>> :FOO
>>
>> julia> @≔ foo :FOO; foo
>> :FOO
>>
>> julia> macro ≔(v, b)
>> e = Expr(:global, v)
>> :(global $e; $(esc(v)) = $(esc(b)))
>>
>> julia> @≔ bar "some bar"; bar
>> "some bar"
>>
>> julia> @≔ bar 7; bar
>> 7
>>
>>
>>
>> El martes, 5 de enero de 2016, 3:18:07 (UTC-6), Julia Tylors escribió:
>> Hi,
>>
>> How can i override the = operator?
>>
>> Thanks
>>
>> function ={T}(x::T,y::T)
>> ...
>> end
>>
>> didn't work
>>
>> Thanks
>
>
