The Process of Compilation

Compilation is an important process in program construction, where high-level programming language code is translated into machine code.
A compiler is a program that carries out this process, transforming the human-understandable programming language into a format that a computer can directly execute.
This process can detect, report, and often fix syntax errors that a programmer might make while writing code.

The first step in compilation is called lexical analysis, where the compiler breaks down the source code into small parts known as tokens. Symbols, keywords, and identifiers are examples of tokens.
Following lexical analysis, syntax analysis takes place. Here, the tokens are examined to ensure they follow the grammatical rules of the language.
Semantic analysis is carried out after syntax analysis. The compiler checks for semantic errors and ensures each statement and expression in the code makes logical sense.
Finally, the compiler generates object code. It also optimizes this code to ensure its efficient execution.

Another method besides compilation to run a program is through interpretation. Interpreters directly execute instructions written in a programming language, while compilers generate a ‘ready to run’ file.
Compiled programs typically run faster than interpreted ones, as they are directly translated into the machine language of the system. Interpreters need to translate the program instruction by instruction each time.
Another advantage of compiled programs is they are independent of their source code once compiled. Interpreted programs need their source code every time they run.

Compilation catches errors before program execution. It provides error messages that can be helpful in debugging the program.
Compiled programs are generally faster and more efficient than interpreted programs as they are in a ready to run state.
A drawback of compilation is that once a program is compiled, it can’t be modified dynamically. Any changes require recompilation.
Compiled programs depend on the architecture and operating system they were compiled on, limiting their portability.

Compiler: The software that transforms source code written in a programming language into machine code or “object code”.
Lexical Analysis: The process of analysing a string of symbols, either in natural language or in computer languages, according to the rules of a formal grammar.
Syntax Analysis: The process of analysing a string of symbols, either in natural language or in computer languages, based on the structure of the language’s grammar.
Semantic Analysis: The phase in which the compiler adds semantic information to the parse tree and builds the symbol table.
Object Code: A sequence of statements or instructions in a computer language, usually machine language.
Interpreter: A program that directly executes instructions written in a programming or scripting language without previously converting them to an object code or machine code.
Debugging: The process of finding and resolving defects or problems within a computer program.