language spec indicates numbers can NOT be converted to bools

[mjkkirschner]

From To	var	number	bool	string	FFI type
var	yes	no	no	no	no
number	yes	yes	no	no	no
bool	yes	no	yes	no	no
string	yes	no	no	yes	no
FFI type	yes	no	no	no	Covariant

but later it says:

Logical operators
&&, ||, !
The operand should be bool type; otherwise type conversion will be incurred.

I am curious if numbers, empty strings, or null should be evaluated as falsey or truthy where bools are expected - ie logical operators, and conditional expressions, or if statements.... @aparajit-pratap you filed a few tasks related to this and I am looking for where this is specified - if it's not specified, let's specify it. @gregmarr @pinzart - what does thunderstorm do?