[julia-users] Re: Macro scoping (or hygiene?) problems
Actually, I do know `d` at compile time - I just hadn't grok-ed quoting and
interpolation well enough to understand how to convey that in code. As it
turns out, what I needed was to create a *symbol* for `d`, so that the
interpolation would get back its *value*: `$(matching(:d))` does the trick.
Thanks for kicking me in the right direction =)
// T
On Tuesday, December 30, 2014 10:09:01 PM UTC+1, Valentin Churavy wrote:
So I do not totally understand the goal of what you are trying to achieve,
but could you try to do this with a macro?
macro value(d)
@show d
quote
println(d at runtime , $d)
end
end
@ngenerate N T function example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)
@nexprs N dim-begin
@nexprs N d-begin
@value(d)
end
end
end
example(rand(2,2), 1.5, 0.7)
So at least the value of d is know at the time when the macro value is run
and you could then call expression generating code based on that value.
dispatching on types of some additional arguments
That sounds like you should/could use staged functions for that.
On Tuesday, 30 December 2014 17:59:37 UTC+1, Tomas Lycken wrote:
I’m doing some metaprogramming for Interpolations.jl, and I’m getting
stuck at an error that I think is due to scoping issues in my nested
quotes, and I’ve stared at this for so long now I’m not getting anywhere.
I can do the following
matching(d) = quote
println(Matching: , $d)
end
nonmatching(d) = quote
println(Not matching: , $d)
end
@ngenerate N T function example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)
@nexprs N dim-begin
@nexprs N d-begin
if d==dim
eval(matching(d))
else
eval(nonmatching(d))
end
end
end
end
example(rand(2,2), 1.5, 0.7)
and get the expected output:
Matching: 1
Not matching: 2
Not matching: 1
Matching: 2
Examining with macroexpand, I see that the eval calls are still there,
but for performance reasons I want to avoid them, so I try to rewrite it to
use eval(ngenerate(...)) instead of @ngenerate ...:
#matching and nonmatching defined as before
ex = ngenerate(
:N,
:T,
:(example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)),
N-quote
@nexprs $N dim-begin
@nexprs $N d-begin
if d==dim
$(matching(d))
else
$(notmatching(d))
end
end
end
end
)
eval(ex)
example(rand(2,2), 1.5, 0.7)
But this doesn’t work: I get ERROR: d not defined on $(matching(d))
(and, if I comment that one out, $(nonmatching(d))). I’ve tried
$(matching($d)) (ERROR: error compiling anonymous: syntax: prefix $ in
non-quoted expression) as well as $(matching(esc(d))) and
$(esc(matching(d))) (both ERROR: d not defined), and I’m at a loss for
what to try (these errors are all thrown at the stage of *defining* the
quoted expression, so macroexpand hasn’t helped me here either, as I
don’t get any expression to call it on…).
Eventually, this will be used to do different things for different array
dimensions like here, but with both matching and nonmatching also
dispatching on types of some additional arguments that I left out for
simplicity, and choosing expressions by means of multiple dispatch this way
is really at the core of Interpolations.jl, so I can’t move the contents of
matching and nonmatching out of their respective functions.
Thanks in advance for any ideas that get me forward,
// Tomas
[julia-users] Re: Macro scoping (or hygiene?) problems
Glad to be of help :)
On Wednesday, 31 December 2014 10:15:14 UTC+1, Tomas Lycken wrote:
Actually, I do know `d` at compile time - I just hadn't grok-ed quoting
and interpolation well enough to understand how to convey that in code. As
it turns out, what I needed was to create a *symbol* for `d`, so that the
interpolation would get back its *value*: `$(matching(:d))` does the trick.
Thanks for kicking me in the right direction =)
// T
On Tuesday, December 30, 2014 10:09:01 PM UTC+1, Valentin Churavy wrote:
So I do not totally understand the goal of what you are trying to
achieve, but could you try to do this with a macro?
macro value(d)
@show d
quote
println(d at runtime , $d)
end
end
@ngenerate N T function example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)
@nexprs N dim-begin
@nexprs N d-begin
@value(d)
end
end
end
example(rand(2,2), 1.5, 0.7)
So at least the value of d is know at the time when the macro value is
run and you could then call expression generating code based on that value.
dispatching on types of some additional arguments
That sounds like you should/could use staged functions for that.
On Tuesday, 30 December 2014 17:59:37 UTC+1, Tomas Lycken wrote:
I’m doing some metaprogramming for Interpolations.jl, and I’m getting
stuck at an error that I think is due to scoping issues in my nested
quotes, and I’ve stared at this for so long now I’m not getting anywhere.
I can do the following
matching(d) = quote
println(Matching: , $d)
end
nonmatching(d) = quote
println(Not matching: , $d)
end
@ngenerate N T function example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)
@nexprs N dim-begin
@nexprs N d-begin
if d==dim
eval(matching(d))
else
eval(nonmatching(d))
end
end
end
end
example(rand(2,2), 1.5, 0.7)
and get the expected output:
Matching: 1
Not matching: 2
Not matching: 1
Matching: 2
Examining with macroexpand, I see that the eval calls are still there,
but for performance reasons I want to avoid them, so I try to rewrite it to
use eval(ngenerate(...)) instead of @ngenerate ...:
#matching and nonmatching defined as before
ex = ngenerate(
:N,
:T,
:(example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)),
N-quote
@nexprs $N dim-begin
@nexprs $N d-begin
if d==dim
$(matching(d))
else
$(notmatching(d))
end
end
end
end
)
eval(ex)
example(rand(2,2), 1.5, 0.7)
But this doesn’t work: I get ERROR: d not defined on $(matching(d))
(and, if I comment that one out, $(nonmatching(d))). I’ve tried
$(matching($d)) (ERROR: error compiling anonymous: syntax: prefix $ in
non-quoted expression) as well as $(matching(esc(d))) and
$(esc(matching(d))) (both ERROR: d not defined), and I’m at a loss for
what to try (these errors are all thrown at the stage of *defining* the
quoted expression, so macroexpand hasn’t helped me here either, as I
don’t get any expression to call it on…).
Eventually, this will be used to do different things for different array
dimensions like here, but with both matching and nonmatching also
dispatching on types of some additional arguments that I left out for
simplicity, and choosing expressions by means of multiple dispatch this way
is really at the core of Interpolations.jl, so I can’t move the contents of
matching and nonmatching out of their respective functions.
Thanks in advance for any ideas that get me forward,
// Tomas
[julia-users] Re: Macro scoping (or hygiene?) problems
So I do not totally understand the goal of what you are trying to achieve,
but could you try to do this with a macro?
macro value(d)
@show d
quote
println(d at runtime , $d)
end
end
@ngenerate N T function example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)
@nexprs N dim-begin
@nexprs N d-begin
@value(d)
end
end
end
example(rand(2,2), 1.5, 0.7)
So at least the value of d is know at the time when the macro value is run
and you could then call expression generating code based on that value.
dispatching on types of some additional arguments
That sounds like you should/could use staged functions for that.
On Tuesday, 30 December 2014 17:59:37 UTC+1, Tomas Lycken wrote:
I’m doing some metaprogramming for Interpolations.jl, and I’m getting
stuck at an error that I think is due to scoping issues in my nested
quotes, and I’ve stared at this for so long now I’m not getting anywhere.
I can do the following
matching(d) = quote
println(Matching: , $d)
end
nonmatching(d) = quote
println(Not matching: , $d)
end
@ngenerate N T function example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)
@nexprs N dim-begin
@nexprs N d-begin
if d==dim
eval(matching(d))
else
eval(nonmatching(d))
end
end
end
end
example(rand(2,2), 1.5, 0.7)
and get the expected output:
Matching: 1
Not matching: 2
Not matching: 1
Matching: 2
Examining with macroexpand, I see that the eval calls are still there,
but for performance reasons I want to avoid them, so I try to rewrite it to
use eval(ngenerate(...)) instead of @ngenerate ...:
#matching and nonmatching defined as before
ex = ngenerate(
:N,
:T,
:(example{T,N}(A::Array{T,N}, xs::NTuple{N,Real}...)),
N-quote
@nexprs $N dim-begin
@nexprs $N d-begin
if d==dim
$(matching(d))
else
$(notmatching(d))
end
end
end
end
)
eval(ex)
example(rand(2,2), 1.5, 0.7)
But this doesn’t work: I get ERROR: d not defined on $(matching(d)) (and,
if I comment that one out, $(nonmatching(d))). I’ve tried $(matching($d))
(ERROR: error compiling anonymous: syntax: prefix $ in non-quoted
expression) as well as $(matching(esc(d))) and $(esc(matching(d))) (both
ERROR:
d not defined), and I’m at a loss for what to try (these errors are all
thrown at the stage of *defining* the quoted expression, so macroexpand
hasn’t helped me here either, as I don’t get any expression to call it on…).
Eventually, this will be used to do different things for different array
dimensions like here, but with both matching and nonmatching also
dispatching on types of some additional arguments that I left out for
simplicity, and choosing expressions by means of multiple dispatch this way
is really at the core of Interpolations.jl, so I can’t move the contents of
matching and nonmatching out of their respective functions.
Thanks in advance for any ideas that get me forward,
// Tomas
