:=

:= is identical to [[be]] assignment and charged method definition : := is also used for constant assignments of variables

square x be x*x
square x := x*x
to square x: x*x

All three are identical.

Difference between symbolic assignment :=, lazy assignment := and direct assignment = :

⚠️ Bad idea:

If symbols in the body of := do not occur on the right hand side, they remain lazy symbols waiting for evaluation.

square := x*x
x = 3
square == 9
x = 4
square == 16

This would be different from function definition to or be where all symbols need to be defined at the time of definition.

Direct assignment = evaluates all symbols not occurring on the left hand side immediately:

square x = x*x # ok
square = x*x # todo: error, unknown symbol x, or treat as := 
x=3
square = x*x # ok, use symbol x from context
square == 9
x = 4
square == 9 # square was fully evaluated when x=3

Contrast the last behavior of square = x*x with
square := x*x
square x := x*x
square x = x*x square = x : x*x

Todo: Ambiguity questions ? Functions are constant too, so both semantics could be reconcilable? Rule: if the right hand side contains a constant than it's a variable. But what if we want to assign some calculated value to a constant? Just assign the value

𝛕=2*calculate_pi()  // calculated on assignment
𝛕:=2*calculate_pi() // calculated every time