Ch3, Section - 3.2 , some notes

Here I noticed two important things...

1. Once we introduce assignment, we can't consider a variable simply a name for a value, instead a variable must somehow designate a *place* where value is stored and with assignment value stored at that place can change.
For this reason, there is a difference between defining a variable and binding it to a value(storing value in the *place*).. in some languages like Oz, variables can exist without a binding and are called *unbound* variables.. and dataflow variables are another special variables which can be bound only once and if unbound then the calling thread waits unless that variable gets a binding.

2. A scheme procedure consists of 3 parts. A parameter list, code in the body and a pointer to the environment where its created. When it is applied *this* is the environment that is extended with bindings for parameters to arguments and not the one in which execution is happening.