Bukkit

If sve code is called from command blocks, @m -variable is a CommandBlockSender instead of a CraftPlayer.

Command block location

@m.getBlock() returns a block object.

local b = @m.getBlock()
local x = b.getX()
local y = b.getY()
local z = b.getZ()

Players near

Use allat-function. Foreach can be used to iterate over all players.

b=@m.getBlock()
foreach(allat(b.getX(),b.getY(),b.getZ(),b.getWorld(),radius))::def (p) { ... }

You can create a function which does that automatically if you want:

def: forallat(radius) {
    local b=@m.getBlock()
    return foreach(allat(b.getX(),b.getY(),b.getZ(),b.getWorld(),radius))
}

# Usage:
forallat(5)::def(p) { ... }

Put function code to a svefile, for example commandblocks.sve, add a svefile declaration to all.sve, and reload svefiles using command /svefile svefiles/all.sve.