Explain the difference between a transpiler and a compiler.

A transpiler converts source code from one programming language to another, while a compiler translates source code into machine code.

A transpiler, also known as a source-to-source compiler, is a type of compiler that takes the source code of a program written in one programming language and translates it into an equivalent program in another language. The output is still at a high level, meaning it is still human-readable and not yet converted into machine code. This is particularly useful when you want to utilise the features of a newer language but need to maintain compatibility with older platforms that don't support it. For example, Babel is a popular JavaScript transpiler that converts ES6 (a newer version of JavaScript) code into ES5 (an older version) to ensure compatibility with older browsers. To further explore how language features can be manipulated, see the page on Understanding and Applying Standard Algorithms.

On the other hand, a compiler is a software that translates source code written in a high-level language into low-level machine code or bytecode. The output is not human-readable but can be directly executed by a computer's CPU. This process involves several stages, including lexical analysis, syntax analysis, semantic analysis, optimisation, and code generation. The primary goal of a compiler is to optimise the code for efficient execution and minimise the usage of system resources. Examples of compilers include the GNU Compiler Collection (GCC) and the Java Development Kit (JDK). The complexity behind compilers is significantly related to their role as language translators, which convert high-level language into machine-executable formats.

A-Level Computer Science Tutor Summary: A transpiler converts code from one high-level programming language to another, keeping it human-readable, while a compiler translates code into machine code, which can be directly executed by a computer. Transpilers are useful for compatibility between different versions of languages, whereas compilers focus on optimising code for efficient execution.