Functions

The most basic way to group lines of Macro code is into a function. Let's write a function to compute wind speed given its U and V vector components.

We've already written code to compute wind speed:

speed = sqrt(u*u + v*v)

We can easily create a function around this code, taking u and v as input parameters. Create a new Macro icon and call it wind_speed. Enter the following into it:

function wind_speed(u, v)
    speed = sqrt(u*u + v*v)
end wind_speed

Within the same macro, read in some wind data and call the function, plotting the result:

u = read('wind_u.grib')
v = read('wind_v.grib')
speed = wind_speed(u,v)

Note that it does not matter where the function is defined in the macro - it will be found.