Lexical analysis.

Lexical analysis is the process of analyzing the structure of a given text or program. It involves breaking down the text into smaller units called tokens. These tokens can be individual words, numbers, symbols, or other meaningful units of the language.

The first step in lexical analysis is to remove any unnecessary characters, such as whitespace or comments, from the text. This helps to simplify the analysis process and focus on the essential elements of the text.

Next, the text is divided into tokens based on predefined rules or patterns. These rules define how different types of tokens are recognized and classified. For example, a rule might specify that a sequence of letters is considered a word token, while a sequence of digits is considered a number token.

During the tokenization process, the lexical analyzer scans the text from left to right, identifying and classifying each token it encounters. It keeps track of the current position in the text and updates it as it progresses.

Once all the tokens have been identified, they are typically passed on to the next phase of the compilation process, such as parsing or semantic analysis. These subsequent phases use the tokens to understand the structure and meaning of the text.

In summary, lexical analysis is an important step in the compilation process that involves breaking down a given text into smaller tokens based on predefined rules. It helps to simplify the analysis process and enables further processing of the text in subsequent phases.