Question

I want to implement a new language, and I would like to do it in C, with the famous flex+yacc combination. Well, the thing is, writing the whole AST code is very time consuming. Is there a tool that automatically generate the constructors for the structs?

I would like something with the following behavior:

input:

enum AgentKind {A_KIND1, A_KIND2};
typedef struct Agent_st
{
    enum AgentKind kind;
    union {
        struct {int a, b, c} k1;
        struct {int a, GList* rest} k2;
    } u;
} Agent;

output:

Agent*    agent_A_KIND1_new(int a, b, c)
{
    Agent* a = (Agent*)malloc(sizeof(Agent));
    a->kind = A_KIND1;
    a->k1.a = a;
    ...
    ...
    return a;
}

Agent*    agent_A_KIND2_new(int a, GList* rest)
{ ... }

Thank you!

Answer 1

Well, since there was no tool I decided to code something this afternoon.
I started something that looks like a nice project, and I would like to continue it.

I coded a somewhat simple (just a bunch of nested folds inside the IO monad) code generator in Haskell, based in builtin haskell types.

The AST type declaration:

http://pastebin.com/gF9xF1vf

The C code generator, based on the AST declaration:

http://pastebin.com/83Z4GH38

And the generated result:

http://pastebin.com/jJPgm5PE

How can somebody not love Haskell?
🙂

ps: I coded this because the project I’m currently working on is going to suffer a huge amount of changes in the near future, and those changes will invalidade the AST, thus forcing me to code another AST module…
Now I can do it quite fast!

Thanks for the answer though.