Automatic Lexical Generator

In this article, we are going to understand automatic lexical generators but before that, we have to understand what is Lexical analysis so let’s understand Lexical Analysis.

Lexical Analysis

Lexical Analysis is the first phase of the compiler, it takes the stream of characters as input and converts that input into tokens also known as tokenization. The token can be classified into various types such as Identifier, Separator, Keyword, Operator, Constant, and Special Character, and further, these tokens will get stored in the symbol table. Lexical Analysis has three phases:

1. Tokenization: It is the process of converting a stream of characters into tokens.
2. Error Messages: The stream of characters we are taking as input is also called lexemes. In this phase we will get error messages related to lexical analysis, It will generate error messages while scanning the input such as illegal characters, unmatched strings, and exceeding length.
3. Comments Elimination: It will eliminate the spaces, tab, and blank spaces and then generates the tokens.

Automatic Lexical Generator

The Automatic Lexical Generator is a tool that generates a code so that we can perform lexical analysis on that to get the output as tokens. This process is used in compiler design and in the field of computer science.

As we have discussed above the process of lexical analysis is to take the stream of characters and later convert it into tokens.

The Lexical Generator includes the following steps:

1. In the first step, we give Lex source program as input to the lexical compiler and it will generate the Lex.yy.c files as output.
2. In the second step, we take Lex.yy.c as input to the C compiler and it will generate the file a.out.
3. And now the output file a.out will take the stream of characters and generates a sequence of tokens as an output.

Advantages of Automatic Lexical Generators

Lexical Generators help overcome many problems such as:

The main usage of Automatica Lexical Generators is to make Lexical analyzers for any language that too in an easy and efficient manner.

1. Making a Lexical analyzer for any programming language is require the same level of design, coding, and practice to generate the output. In that case, Lexical Generator works efficiently.
2. It is very difficult to make Lexical analyzers for every programming language as it is a very sophisticated process and with the help of Lexical generators we can solve that problem.