Read

read puts into a variable something taken from someone, by address. Who that someone is is decided by the second field, and what the address means depends on it too:

Who we read from	What the address means	What we get
a memory cell or bank	a slot number, from zero	a number or an object
another processor	a variable name in quotes	its variable or its link
a string	a character index, from zero	the character’s code

These cases have more in common than it seems: an address out of range is never an error anywhere, and the answer is always emptiness. A block that cannot be read from answers with the same.

Lessons

1. The memory cellA processor's memory dies with every edit to the program. A cell remembers — and you fetch from it by slot number
2. Another processor's variablesA cell for exchanging values isn't always needed: a neighbour's variable can be taken straight from it, by name
3. A character from a stringA string is read by address too: a character index instead of a slot number, a character code instead of a value

What you need first

«Links and getlink» — how a processor sees neighbouring blocks at all, and «Emptiness: null» — how it differs from zero. The lessons will tell you the rest themselves.