What is the difference in using local or <- for a global variable?
//top of device code local t = 1; t1 <- 2;
This is explained here: http://electricimp.com/docs/resources/efficientsquirrel/ (along with some other interesting notes about Squirrel).
Choose between top-level locals and globals Variables declared "local" at the top level, i.e. apparently not in any function, are in fact local to a notional "main()" function that corresponds to the main program. They look like this:
local r=0,g=0,b=0;If you have a huge number of such top-level locals, they can take up extra run-time memory and extra code size compared to using global members of the root table, which look like this:
r <- 0; g <- 0; b <- 0;However, using locals will be faster – and may become faster still in future, as it makes optimisation of the code easier. Also, locals are discarded once nothing references them, whereas globals are forever: this means that, for instance, “local” functions only used during your program’s setup will be automatically discarded from run-time memory once no longer needed.
Thanks. I see it both ways in some examples. If I have a blob at the top of my Device code for serial data, should I use local or <- ?