Parser is inaccurate: "100 °C to °F) / 3": is evaluated to "approx. 70.6666666666 °F"

[yurivict]

There is no opening brace, so technically this is an invalid expression, and it shouldn't be evaluated like this.

[printfn]

Unmatched parentheses are an intentional feature, it's really useful to be able to insert ) anywhere and have the parser automatically insert an opening bracket at the start of the input.

[yurivict]

How does it know where to insert the opening parenthesis? Maybe it isn't intended to be at the beginning?
Generally such guessing would be ambiguous.

[printfn]

Yeah, opening parentheses are inserted at the beginning of input, and closing brackets at the end. At some point it might make sense to account for statements (e.g. a = 1+2; a + 1)/2) when inserting parentheses, but I think the usefulness for simple expressions still outweighs the ambiguity.