Programming Language Concepts

Describe 4 Key Attributes of Good Programming Languages with Examples

• Expressiveness & Conciseness: Ability to represent computations naturally with minimal boilerplate code (e.g., Python's list comprehensions, higher-order functions)

• Flexibility & Complexity: Ability to handle a wide range of use cases, even at the cost of making the language more complex (e.g., C++’s multiple inheritance, macros)

• Safety & Readability: Catching errors early while ensuring code is easily understood (e.g., Haskell's strong typing, Python's whitespace structure)

• Efficiency & Abstraction: Balancing performance with support for code reuse (e.g., C's memory control, Java's interface system)

• Learnability & Library Support: Can be mastered in reasonable time with comprehensive libraries (e.g., Python's ecosystem for data science)

What are the key programming language concepts and what they cover.

• Data Types and Values:

  Representation of different data kinds (numbers, strings, composites)

  Type systems (static vs. dynamic, strong vs. weak)

  Type checking and inference

• Control Structures:

  Sequencing operations

  Conditional execution (if/else, switch/case)

  Iteration (loops, recursion)

• Variables and Scope:

  Declaration, initialisation, and lifetime

  Lexical vs. dynamic scope

  Variable binding mechanisms

• Abstraction Mechanisms:

  Functions, methods, and procedures

  Parameters and return values

  Information hiding, encapsulation, inheritance, polymorphism

• Concurrency: Threading models, Synchronisation techniques, Communication between threads

How do modern language implementations approach execution?

• Modern language implementations only use interpreters, as compiling code before execution is no longer necessary.

• All modern languages are compiled directly to machine code ahead of time, completely eliminating the need for any runtime environment.

• Modern implementations avoid using JIT compilers because they significantly slow down program execution compared to traditional interpreters.

• Modern language implementations often blur the distinctions between interpretation and compilation, with many interpreted languages using JIT compilation and compiled languages including runtime systems.

What are the fundamental capabilities that programming languages typically provide.

• Structure and represent data in memory

• Perform operations on that data

• Handle input/output and respond to events

• Support direct hardware manipulation without the need for operating system intervention.

• Control execution flow based on conditions and data values

What abstraction do programming languages provide?

• Programming languages abstract away all complexity by automatically generating efficient algorithms and managing all data structures internally without input from the programmer

• Programming languages provide an abstraction that allows programs to run independently of any hardware or operating system, removing the need for any underlying infrastructure to execute code.

• Programming languages create an abstraction layer that shields programmers from low-level computer architecture (registers, memory management) while being precise enough to translate efficiently to machine code.

• They offer an abstraction that fully replaces traditional programming logic with human-readable natural language, making code writing accessible without any formal training in computer science.

What are two hybrid approaches to program execution?

• Bytecode Interpretation: Code is compiled to an intermediate form (Java VM, Python bytecode)

• Static Interpretation: Programs are interpreted at compile time to eliminate the need for runtime execution entirely.

• Just-In-Time (JIT) compilation: Code is compiled at runtime (Java, Modern JavaScript)

• Source Code Streaming: Code is executed directly from source files line-by-line across a distributed network to optimize latency.

• Predictive Execution: The system guesses future user inputs and compiles potential execution paths in advance to speed up performance.

What is compilation in program execution?

• Compilation happens only during program execution, translating each line of code just before it runs to ensure maximum accuracy.

• Compilation stores program logic in a graphical format that modern CPUs can interpret visually, removing the need for written code.

• Compilation allows a program to be run directly by the CPU without ever translating it into machine code, making development faster but less secure.

• A compiler translates the program to machine code before execution.

  Common for C, Ada, Haskell.

  Advantages: Faster execution, optimisation opportunities.

  Disadvantages: Requires separate compilation step, harder to port.