Difference between revisions of "Lex Tutorial"

From MKWiki
Jump to navigation Jump to search
Line 4: Line 4:
 
* The lexical analyzer is a program that transforms an input stream into a sequence of tokens.
 
* The lexical analyzer is a program that transforms an input stream into a sequence of tokens.
 
* It reads the input stream and produces the source code as output through implementing the lexical analyzer in the C program.
 
* It reads the input stream and produces the source code as output through implementing the lexical analyzer in the C program.
 +
===The function of Lex is as follows:===
 +
* Firstly lexical analyzer creates a program lex.1 in the Lex language. Then Lex compiler runs the lex.1 program and produces a C program lex.yy.c.
 +
* Finally C compiler runs the lex.yy.c program and produces an object program a.out.
 +
* a.out is lexical analyzer that transforms an input stream into a sequence of tokens.

Revision as of 00:31, 10 August 2020

Phases of Compilation

Lex

  • Lex is a program that generates lexical analyzer. It is used with YACC parser generator.
  • The lexical analyzer is a program that transforms an input stream into a sequence of tokens.
  • It reads the input stream and produces the source code as output through implementing the lexical analyzer in the C program.

The function of Lex is as follows:

  • Firstly lexical analyzer creates a program lex.1 in the Lex language. Then Lex compiler runs the lex.1 program and produces a C program lex.yy.c.
  • Finally C compiler runs the lex.yy.c program and produces an object program a.out.
  • a.out is lexical analyzer that transforms an input stream into a sequence of tokens.