let allows local variables to be declared and to be initialized to specified values.
| (let | ( (var_1 value_1 ) |
| ... | |
| (var_n value_n ) ) | |
| form_1 | |
| ... | |
| form_n ) |
The variables var_i are initialized to the values value_i (in some unspecified order) when the let is entered; their values may be changed using set!.
The variables var_i can be accessed by any code or procedure that is inside the let, that is, within the scope of the let. The scope of a variable is the area of program text within which it can be referenced.
The body of the let, form_1 ... form_n, is executed in order, just like a begin.
The value of the let is the value of form_n, which could be just a variable name.