doathe / flex-bison-example

A compiler and interpreter of a toy language. Using C++, Flex and Bison.

Flex & Bison example

A compiler and interpreter of a toy language. Using C++, Flex and Bison.

The toy language

The language is called the While language. Its different variants often serve educational purposes. It has two types (boolean and natural), expressions of these two types, assignment instruction, reading from standard input, writing to standard output, branching and looping.

See the test/*.ok files to learn the syntax and semantics of the language.

Building the project

Make sure you have g++, flex, bison and nasm installed. The project was tested with the following versions: g++ 6.3.0, flex 2.6.1, bison 3.0.4, nasm 2.12.01. It might work with other versions as well.

Use the following command to build the project:

make

Use the following command to run tests:

make test

Use the following command to cleanup all generated files:

make clean

Using the interpreter

The following command executes a While program immediately:

./while -i path/to/your/while.program

Using the compiler

The following command compiles a While language program to NASM assembly:

./while -c path/to/your/while.program > output.asm

To further compile the assembly program to an executable:

nasm -felf output.asm
gcc output.o io.c -o output

Note: Under 64 bit operating systems, pass the -m32 option to gcc. To run the executable output:

./output

License

This software is licensed under the MIT license. See the LICENSE file for details.