Difference between revisions of "Lex Tutorial"
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[[File:Compilation phases.png|thumb|Phases of Compilation]] | [[File:Compilation phases.png|thumb|Phases of Compilation]] | ||
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==Lex == | ==Lex == | ||
* Lex is a program that generates lexical analyzer. It is used with YACC parser generator. | * Lex is a program that generates lexical analyzer. It is used with YACC parser generator. | ||
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* 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:=== | ===The function of Lex is as follows:=== | ||
| + | [[File:Lex.png|thumb| Running Lex Programs]] | ||
* 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.''' | * 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.''' | * 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.''' | * '''a.out''' is lexical analyzer that transforms an input stream into a '''sequence of tokens.''' | ||
Revision as of 00:43, 10 August 2020
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.
