James Bigler wrote:
On Tue, Jan 27, 2009 at 10:46 AM, Matthew Woehlke <
mw_tr...@users.sourceforge.net> wrote:
James Bigler wrote:
I have the following code in a script:
function(set_var var)
message("var = ${var}")
message("${var} = ${${var}}")
set(${var} "new_val")
message("${var} = ${${var}}\n")
endfunction()
set(myvar 10)
set_var(myvar)
# Empty variable
set_var(myvar2)
set_var(var)
# Set variable
set(var 11)
set_var(var)
When I run it I get the following output:
var = myvar
myvar = 10
myvar = new_val
var = myvar2
myvar2 =
myvar2 = new_val
var = var
var = var
new_val =
var = var
var = var
new_val =
I get expected output when the name of the variable I pass in isn't the
same
as the one used in the function parameter list.
Is this the desired behavior of the language? I would argue that it
isn't,
because you get different behavior based on the name of the variable
passed
in.
Um... and how would you claim it is supposed to work? You've got a classic
case of variable shadowing here. If you think about it, CMake is doing
exactly what you told it to do.
Grrrr....I see that now.
${var} evaluates to var and there's no way to know if that's the function's
var or the global scope's var.
Right :-).
I know you could probably mangle the parameter names to decrease the
probability of collisions, but is there any assured method to avoid
collisions?
I doubt there is a technical way to do it (it would be complicated, with
questionable value compared to the cost). Enforcing a good naming scheme
is probably your best bet; you could, for example, prefix parameter
names with the name of the function.
--
Matthew
Please do not quote my e-mail address unobfuscated in message bodies.
--
Anyone who is capable of getting themselves made President should on no
account be allowed to do the job. -- Douglas Adams
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