Generate Lexical Analyzers with Flex | Online Free DevTools by Hexmos

Generate C code for lexical analyzers with Flex. This powerful tool simplifies the creation of scanners from Lex files. Free online tool, no registration required.

flex

Lexical analyzer generator. Given the specification for a lexical analyzer, generates C code implementing it. More information: https://manned.org/lex.1.

  • Generate an analyzer from a Lex file, storing it to the file lex.yy.c:

flex {{analyzer.l}}

  • Write analyzer to stdout:

flex {{[-t|--stdout]}} {{analyzer.l}}

  • Specify the output file:

flex {{analyzer.l}} {{[-o|--outfile]}} {{analyzer.c}}

  • Generate a batch scanner instead of an interactive scanner:

flex {{[-B|--batch]}} {{analyzer.l}}

  • Compile a C file generated by Lex:

cc {{path/to/lex.yy.c}} -o {{executable}}