vig/src/ast.zig

const std = @import("std");
const tokens = @import("tokens.zig");
const Token = tokens.Token;

pub const NodeList = std.ArrayList(*Node);
pub const ParamList = std.ArrayList(ParamDecl);
pub const ConstList = std.ArrayList(SingleConst);

// TODO convert FnCall to something like PrefixOp / InfixOp / SuffixOp
pub const NodeType = enum {
    Root,
    FnDecl,
    FnCall,
    ConstDecl,
    String,
};

pub const ParamDecl = struct {
    name: Token,

    // TODO types
    typ: Token,
};

pub const FnDecl = struct {
    func_name: Token,
    params: ParamList,
    body: NodeList,
};

pub const FnCall = struct {
    func_name: Token,
    arguments: NodeList,
};

pub const SingleConst = struct {
    name: Token,

    // TODO expr
    value: Token,
};

pub const Node = union(NodeType) {
    Root: NodeList,
    FnDecl: FnDecl,
    ConstDecl: ConstList,
    FnCall: FnCall,
    String: Token,
};

pub fn mkRoot(allocator: *std.mem.Allocator) !*Node {
    var node = try allocator.create(Node);
    node.* = Node{ .Root = NodeList.init(allocator) };
    return node;
}

fn print(ident: usize, comptime fmt: []const u8, args: ...) void {
    var i: usize = 0;
    while (i < ident) : (i += 1) {
        std.debug.warn("\t");
    }

    std.debug.warn(fmt, args);
}

pub fn printNode(node: *Node, ident: usize) void {
    switch (node.*) {
        .FnDecl => |decl| {
            print(ident, "FnDecl name='{}'\n", decl.func_name.lexeme);

            for (decl.params.toSlice()) |param| {
                print(
                    ident + 1,
                    "param: '{}' {}\n",
                    param.name.lexeme,
                    param.typ.lexeme,
                );
            }
        },

        .ConstDecl => |consts| {
            print(ident, "ConstDecl ({} consts)\n", consts.len);
            for (consts.toSlice()) |const_decl| {
                print(
                    ident + 1,
                    "'{}' = '{}'\n",
                    const_decl.name.lexeme,
                    const_decl.value.lexeme,
                );
            }
        },

        .Root => {
            for (node.Root.toSlice()) |child| {
                printNode(child, ident + 1);
            }
        },

        else => {
            print(ident, "unknown node: {}\n", node);
        },
    }
}