shorthands for var and const declarations, and infer types #1289
Description
This is for post-MVP.
We have a principle that expressions be (mostly) strongly typed.
We are also a bit hung up on possibly renaming 'const' and introducing 'constexpr' for closely related concepts. See #1272
I have been hoping to reduce wordiness along the following lines, for code inside a function body:
Before:
var a : i32 = 12;
var b : i32 = 13;
const expr : i32 = 1+2;
const acopy : i32 = a; // Gets the value stored in a.
const aptr : ptr<function,i32> = a; // Gets the the pointer to a's storage.
After:
var a: i32 = 12; // same as before
var b = 13; // type inference
expr := 1+2; // introduces new name 'expr' for the evaluation of 1+2. Infer type.
acopy := a; // gets the value stored in a.
aptr ~= a; // gets reference to the storage for a. Think of ~ as rope "tying" you to the storage.
Note that expr, acopy, aptr, are still 'const'. They are not re-assignable.
Also, variables can't store pointers, so there is no desire/need/use-case for var a ~= ...
fix typo var b : = 13; -> var b = 13; per @mehmetoguzderin suggestion.