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added @macroexpand #18660

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Sep 30, 2016
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added @macroexpand #18660

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988f7a1
added @macroexpand
jw3126 Sep 24, 2016
bff375b
Update expr.jl
jw3126 Sep 24, 2016
0b2c3ca
added @macroexpand to rst
jw3126 Sep 24, 2016
2dfe407
fix
jw3126 Sep 25, 2016
691052d
fixup: improving docu and removing test/expr.jl
jw3126 Sep 29, 2016
ebe9b53
fixup
jw3126 Sep 29, 2016
c66c096
Update expr.jl
jw3126 Sep 29, 2016
f8157dc
Update choosetests.jl
jw3126 Sep 29, 2016
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6 changes: 3 additions & 3 deletions base/expr.jl
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Expand Up @@ -88,9 +88,9 @@ julia> macro m()
julia> M.f()
(1,2)
```
With @macroexpand the expression expands where @macroexpand appears in the code (module M).
With macroexpand the expressions expands in the current module where the code was finally called.
Note that when calling macroexpand or @macroexpand directly from the REPL, both of these contexts coincide, hence there is no difference.
With `@macroexpand` the expression expands where `@macroexpand` appears in the code (module `M`).
With `macroexpand` the expressions expands in the current module where the code was finally called (REPL).
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this isn't the repl if the function is run in a script, is it?

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Let me explain it differently. If you call macroexpand, the expansion takes place at runtime. If you call @macroexpand the expansion takes place at compile time (when @macroexpand is expanded to be more precise.). So the context of @macroexpand is where it appears in the code, while the context of macroexpand is the current environment. So if you run M.f() from a script, the answer will be
(1, whatever @m() currently means in your script)
Does this answer the question?

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That makes sense. I'm referring to the "where the code was finally called (REPL)." here. I don't see why "(REPL)" is accurate.

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But in the example it is the REPL?

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You're making a general statement here "with macroexpand the expression expands` ... followed by a very not-general parenthetical that doesn't serve much purpose

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The julia> in the example implies that it runs in the REPL, doesn't it? And the "(module M)" in the sentence before also makes sense only in context of the example. So I'd say either leave as is or rephrase as "(module M in the example)" and "(REPL in the example)" (which I could well do in #18784).

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@martinholters I am happy with either formulation, so rephrase it as you see fit.

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a few words saying "in the example" sounds like a good clarification, thanks

Note that when calling `macroexpand` or `@macroexpand` directly from the REPL, both of these contexts coincide, hence there is no difference.
"""
macro macroexpand(code)
code_expanded = macroexpand(code)
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