What is this?
C4 is a tiny, self-hosting compiler and interpreter for a small subset of the C language, written in just four functions as an exercise in extreme minimalism.
C4 is a tiny, self-hosting compiler and interpreter for a small subset of the C language, written in just four functions as an exercise in extreme minimalism.Is it a compiler or an interpreter?It's both: c4 parses C source code and then executes it directly through its own built-in virtual machine, rather than producing a separate binary. It's even capable of compiling and running its own source code.
It's both: c4 parses C source code and then executes it directly through its own built-in virtual machine, rather than producing a separate binary. It's even capable of compiling and running its own source code.How do I get it running?Compile the single source file with 'gcc -o c4 c4.c', then run it against a C file, for example './c4 hello.c'.
Compile the single source file with 'gcc -o c4 c4.c', then run it against a C file, for example './c4 hello.c'.Do I need anything besides a C compiler?No, all you need is a standard C compiler like gcc to build the single c4.c file; there are no other dependencies.
No, all you need is a standard C compiler like gcc to build the single c4.c file; there are no other dependencies.Does it support the full C language?No, c4 only implements the small subset of C needed to compile itself (char, int, pointers, basic control flow), not the full C standard.
No, c4 only implements the small subset of C needed to compile itself (char, int, pointers, basic control flow), not the full C standard.Does it work on Linux, macOS, and Windows?Since it's just a standard C source file built with gcc, it runs anywhere a C compiler is available, including Linux, macOS, and Windows.
Since it's just a standard C source file built with gcc, it runs anywhere a C compiler is available, including Linux, macOS, and Windows.What do the four functions actually do?The entire compiler is organized into a tokenizer, an expression parser, a statement parser, and a main driver function, together handling lexing, parsing, code generation, and execution.
The entire compiler is organized into a tokenizer, an expression parser, a statement parser, and a main driver function, together handling lexing, parsing, code generation, and execution.What does the '-s' flag do?Running './c4 -s hello.c' prints the generated virtual machine instructions alongside the source, letting you see exactly how c4 translates your code.
Running './c4 -s hello.c' prints the generated virtual machine instructions alongside the source, letting you see exactly how c4 translates your code.Why run './c4 c4.c c4.c hello.c'?This chains c4 interpreting itself interpreting itself to run a program, demonstrating that c4 is self-hosting and can compile and execute its own source code.
This chains c4 interpreting itself interpreting itself to run a program, demonstrating that c4 is self-hosting and can compile and execute its own source code.Who is this project for?It's aimed at people curious about how compilers and interpreters work internally, not for writing real-world C programs.
It's aimed at people curious about how compilers and interpreters work internally, not for writing real-world C programs.What are similar projects?lua, craftinginterpreters, acwj, chibicc, the-super-tiny-compiler, lytlnyblOS, cpython, gcc
lua, craftinginterpreters, acwj, chibicc, the-super-tiny-compiler, lytlnyblOS, cpython, gccWhich topics is it in?compilers, from-scratch, interpreter, educational, programming-language, gplv2, computer-science, compiler, c, learning, command-line-tool, education
compilers, from-scratch, interpreter, educational, programming-language, gplv2, computer-science, compiler, c, learning, command-line-tool, education