regex and to_number()

Consider this code:

local x = 'aaabbb12345'
local y = x.gsub('[ab]+', '')

Then try to print the info like this:

A = <%=Luan.to_number(y)%>
B = <%=Luan.to_number(x.gsub('[ab]+', ''))%>

The output is:

A = 12345
B = nil

Why?

The problem is that gsub returns 2 values, the second value being the number of matches.  So you are calling to_number("12345",1) .  The second arg to to_number() is the base, and since this isn't valid, it returns nil.

I followed Lua in having to_number() return a nil when there is an error, but maybe I should throw an error.  The error in this case would be "radix 1 less than Character.MIN_RADIX" (from java).  What do you think?

Another option is to put to_number in the String module.  Then you would have:

A = <%=y.to_number()%>
B = <%=x.gsub('[ab]+', '').to_number()%>

If you want to use a base, you could do:

from hex = <%="1a".to_number(16)%>

fschmidt wrote

Another option is to put to_number in the String module.  Then you would have:

A = <%=y.to_number()%>
B = <%=x.gsub('[ab]+', '').to_number()%>

If you want to use a base, you could do:

from hex = <%="1a".to_number(16)%>

I guess String to Number is 99.9% of the cases, so this suggestion is fine.

done in rev 8b2db645b9b2

Thanks. Closing thread.