Grammatical analysis is the core part of the translation process, and the study of grammatical analysis methods has considerable practical value. This paper introduces the design and implementation of a parser. Firstly, this paper briefly divides the compiler's work into five stages: lexical analysis, grammatical analysis, semantic analysis, code generation, optimization and object code generation, and describes the function of the parser and its role in the whole compiler's work. Secondly, it focuses on the research methods of constructing a parser. Finally, the grammatical structure analysis of a small language (here refers to a subset of Pascal language) is realized by c++language.

Keywords: parser, context-free grammar, top-down analysis, bottom-up analysis, predictive analysis table.