module sema.SymbolTable;

import tango.io.Stdout;

import lexer.Token,
       ast.Exp;

public
import sema.Symbol;

class Scope
{
    this() {}
    this(Scope enclosing)
    {
        this.enclosing = enclosing;
        this.func = enclosing.func;
    }

    Scope enclosing;

    Symbol add(Identifier id)
    {
        auto s = new Symbol;
        s.id = id;
        symbols[id] = s;
        return s;
    }

    Symbol find(Identifier id)
    {
        if (auto sym = id in symbols)
            return *sym;
        if (enclosing !is null)
            return enclosing.find(id);
        return null;
    }

    Symbol findType(Identifier id)
    {
        if (auto sym = id in symbols)
            if(symbols[id].type == null)
                return *sym;
        if (enclosing !is null)
            return enclosing.find(id);
        return null;
    }

    char[][] names()
    {
        char[][] res;
        if (enclosing)
            res = enclosing.names;
        foreach (id, sym; symbols)
            res ~= sym.id.name ~ " : " ~ sym.type.name;
        return res;
    }

    Symbol parentFunction()
    {
        if (func !is null)
            return func;
        else if (enclosing !is null)
            return enclosing.parentFunction();
        else
            return null;
    }

    int opEquals(Object o)
    {
        return this is o;
    }

    char[] toString()
    {
        if (func)
            return Stdout.layout.convert("{}: {}", func.id.get, symbols.length);
        return "root";
    }

    Symbol parentFunction(Symbol f)
    {
        func = f;
        return f;
    }
private:
    Symbol[Identifier] symbols;
    Symbol func;
}