Update spec

spec.txt

@@ -46,7 +46,7 @@ Literals:
     123ul  -> u64
     3.14h  -> f16
     3.14   -> f32
-    3.14l  -> f64
+    3.14d  -> f64
     'a'    -> u8 (ascii only?)
     '猫'u  -> u32
 
@@ -85,11 +85,11 @@ Logical (only bool type):
     x || y // short-circuit
     x ^ y
 
-Equality (all built-in types, all pointer types, all array/struct types, only same type):
+Equality (all built-in types, all pointer types, all array/struct types, only same type unless integers):
     x == y
     x != y
 
-Comparison (all built-in types, all pointer types, all array/struct types, only same type):
+Comparison (all built-in types, all pointer types, all array/struct types, only same type unless integers):
     x < y
     x > y
     x <= y
@@ -103,7 +103,7 @@ Bitwise (integer types, only same type):
     x || y // short-circuit
     x ^ y
 
-Bitwise shift (any pair of integer types):
+Bitwise shift (any integer + any unsigned integer type):
     x >> y
     x << y
 
@@ -124,6 +124,7 @@ Pointer arithmetic works element-wise (like C or C++), i.e. p + n advances by n
 Casting:
     x as u32 // always explicit, no implicit casts allowed
 
+The only implicit casting allowed is T mut* -> T* (maybe?)
 Any integer/floating-point types can be cast to each other.
 Any pointer types can be cast to each other (TODO: alignment? UB or safe fallback? Probably UB.)
 
@@ -148,6 +149,7 @@ Flow control:
     while condition:
         statements
 
+    TODO: break/continue?
     TODO: for loops? iterator/range interface?
 
 ======== STRUCTS ========
@@ -167,6 +169,8 @@ Struct field access:
     let p = &r
     let y = p.height // field access through pointer is the same
 
+TODO: inner struct functions maybe? to act as namespace/module containers
+
 ======== FUNCTIONS ========
 
 Function definition:
@@ -176,6 +180,10 @@ Function definition:
     func bar(x: f32): // deduced return type unit
         print(x)
 
+    // External function: name taken literally as `powf`
+    // and C calling convention assumed
+    foreign func powf(x: f32, y: f32) -> f32 // no implementation
+
 TODO: function overloading? Probably requires selecting a specific overload using `as` operator to save to a value (but not on call site)
 
 ======== TYPE OF TYPES ========