Update plans

backlog.txt

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-* Mutually recursive functions
-* Figure out indentation: keep tabs - what to do with printing errors? Enforce e.g. 4 spaces?

plans.txt

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+Future plans:
+* Rewrite identifier resolution using visitors
+* Default-constructing (no arguments, zero-initialization) primitive types & struct types
+* Introduce type checking & inference as a separate pre-execution/compilation AST pass + add type information into expression nodes
+* Pointers: pointer types, address-of operator (&), dereferencing, scope-based lifetime tracking in interpreter
+* Function overloading: separate functions from values (again) in interpreter, allow casting to specific function type to take function value
+* Const propagation: annotate expression AST nodes that are computable in compile-time
+* Generic parameters: can be either values or `t : type`, but always compile-time
+* Generic structs: `struct <t : type, n : u64> array:`, require explicitly specifying parameters when instantiated (used as a type or creating a value)
+* Generic functions: `func <t : type, n : u64> max(a : t[n]):`, require explicitly specifying parameters when called or converted to function pointer
+* Generic parameter inference for functions & structs
+* Extension functions: operator overloading, destructors, iterators & for loop, move assignment (replaces built-in copy)
+* Metaprogramming: assigning types to variables (of type `type`), functions can take `type` as regular arguments and return `type`, all type computations are compile-time only
+
+Backlog:
+* Mutually recursive functions
+* Figure out indentation: keep tabs - what to do with printing errors? Enforce e.g. 4 spaces?
+* Default-constructing primitive types
+* Empty array expression
+* Calling functions as methods