>From docs:
macro r_str(p)
> Regex(p)
> end
>
>
> That’s all. This macro says that the literal contents of the string
> literal r"^\s*(?:#|$)" should be passed to the
> @r_str macro and the result of that expansion should be placed in the
> syntax tree where the string literal occurs. In
> other words, the expression r"^\s*(?:#|$)" is equivalent to placing the
> following object directly into the syntax
> tree:
> Regex("^\\s*(?:#|\$)")
>
>
> Not only is the string literal form shorter and far more convenient, but
> it is also more efficient: since the regular
> expression is compiled and the Regex object is actually created when the
> code is compiled, the compilation occurs
> only once, rather than every time the code is executed. Consider if the
> regular expression occurs in a loop:
> for line = lines
> m = match(r"^\s*(?:#|$)", line)
> if m == nothing
> # non-comment
> else
> # comment
> end
> end
>
> Shouldn't the compiler optimize this code *on its own* like this ?
re = Regex("^\\s*(?:#|\$)")
for line = lines
m = match(re, line)
if m == nothing
# non-comment
else
# comment
end
end
This is kind of optimization which is really easy to detect and and execute.
How is that so that julia is not able to do that?
