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Expressions, values, and types
Evaluation of an expression yields a value which belongs to a type
- Expressions
- Written by the programmer
- Will typically involve one or more function calls
- A Function - as written by the programmer - is itself an expression
- Values
- Primitive as well as composite
- A function expression is evaluated to a function object
- Types
- A set of values with common properties
- Type checking can be used to validate a program for certain errors before it is executed