Programing Languages

A computer execute programs written in many different programming languages

Machine languages: statements are interpreted by the hardware itself
- A fixed set of instructions invoke operations implemented by the circuitry of the central processing unit
- Operations refer to specific hardware memory addresses; no abstraction mechanisms
High-level languages: statements and expressions are intepreted by another program or compiled into another language
- Provide means of abstraction such as naming, function definition, and objects
- Abstract away system details to be independent of hardware and operating systems

python

from dis import dis
def square(x):
    return x * x
dis(square) # Display a lower level implementation similar to machine language

Metalinguistic Abstraction

A powerful form of abstraction is to define a new language that is tailored to a particular type of application or problem domain

Components:

Syntax: The legal statements and expressions in the language
Semantics: The execution/evaluation rule for those statements and expressions

Necessities:

Specification: A document describe the precise synbax and semantics of the language
Canonical Implementation: An interpreter or compiler for the language