Definition
A parser is a software component that fractionalizes the source code into smaller, manageable parts that software programs can understand and use.
It generates a data structure from the input, typically depicted as a logical diagram (a parse tree). This enables software programs to interpret the context of each part of the source code and understand how it relates to the underlying structure.
Types of Parser
- Top-down parsing: In this type, the parsing process commences with the start symbol and forms parse trees from the root node.
- Bottom-up parsing: This is where parsing begins at the leaf node through the root node and ends at the start symbol.
Stages of Parsers
- A lexical analyzer: The parser processes the input data and breaks it down to create a sequence of tokens, which are the basic units of meaning such as operators, keywords, literals, identifiers, or symbols.
- Syntactic analysis: In this stage, the parser checks the sequence of the tokens to ensure they follow the grammatical rules of the programming language.
- Semantic parsing: The parser checks if the tokens are semantically consistent with the programming language.