ast_printer: print scopes inside functions

- comp_ctx: add children attr for debug info

examples/hello.ry

@@ -3,7 +3,7 @@ const (
 )
 
 fn f() i32 {
-    var a = 3;
+    //var a = 3;
     return 2;
 }
 

src/ast_printer.zig

@@ -369,6 +369,19 @@ fn prettyType(typ: SymbolUnderlyingType) []const u8 {
     };
 }
 
+pub fn printScope(scope: *Scope, ident: usize) void {
+    print(ident, "scope at addr {}\n", scope);
+
+    var it = scope.env.iterator();
+    while (it.next()) |kv| {
+        print(ident, "sym: {}, typ: {}\n", kv.key, prettyType(kv.value));
+    }
+
+    for (scope.children.toSlice()) |child| {
+        printScope(scope, ident + 1);
+    }
+}
+
 pub fn printContext(ctx: CompilationContext) void {
     var it = ctx.symbol_table.iterator();
 
@@ -389,6 +402,10 @@ pub fn printContext(ctx: CompilationContext) void {
                         prettyType(param_kv.value),
                     );
                 }
+
+                // go through scopes
+                std.debug.warn("scope info:\n");
+                printScope(fn_sym.scope, 0);
             },
 
             .Struct => |typemap| {

src/comp_ctx.zig

@@ -30,18 +30,23 @@ pub const SymbolUnderlyingType = union(SymbolUnderlyingTypeEnum) {
 };
 
 pub const Environment = std.StringHashMap(SymbolUnderlyingType);
+pub const ScopeList = std.ArrayList(*Scope);
 pub const Scope = struct {
     parent: ?*Scope,
     env: Environment,
 
+    /// Used for debug information.
+    children: ScopeList,
+
     allocator: *std.mem.Allocator,
 
     pub fn create(allocator: *std.mem.Allocator, parent: ?*Scope) !*Scope {
         var scope = try allocator.create(Scope);
 
         scope.* = Scope{
-            .parent = scope,
+            .parent = parent,
             .env = Environment.init(allocator),
+            .children = ScopeList.init(allocator),
             .allocator = allocator,
         };
         return scope;
@@ -58,7 +63,7 @@ pub const Scope = struct {
 
 // functions, for our purposes, other than symbols, have:
 //  - a return type
-//  - TODO parameters
+//  - parameters
 pub const FunctionSymbol = struct {
     decl: ast.FnDecl,
     return_type: SymbolUnderlyingType,