NEP14 Stringification

This proposal suggests a uniform scheme for converting data values to strings.

Goals

• The print() function, with a string, should print that string verbatim.
• The print() function should accept any value of any type and print a readable (though perhaps in some cases not useful) representation.
• String interpolation should follow the same rules as for the print() function.
• The .toString() method should return a readable string representation of the value, and for value of type String it should return just the value.

Current status

> LET s: String := "hello"
> print(s)
hello
> print(s.toString())
"hello"
> print("\(s)")
hello

Here, the \(s) string interpolation calls .toString() on the value, except for type String, where it doesn't.

Proposal

The .toString() method, for each type, will return:

Type	Result	Example
Boolean	Literal boolean value	FALSE
Number	String representation of number	1.234
String	The same string	hello
Bytes	Hex notation	HEXBYTES "01 02 03"
ENUM	Enum item name	red
Array	Literal array with quoted strings	["foo", "bar"]
Dictionary	Literal dictionary with quoted keys and string values	{"name": "foo", "value": 5}
RECORD	Literal record form	Item(name WITH "foo", value WITH 5)
POINTER	Pointer with literal class form	0x12345678->Item(name WITH "foo", value WITH 5)
Object	Result of .toString() call on object	dependent on object

String interpolation will always call .toString() on the interpolated value.

A new function string.quote() will quote a given string in a form that would be acceptable in source code:

VAR s: String := "hello"
> print(s)
hello
> print(string.quote(s))
"hello"
> s := s + string.fromCodePoint(34) + "world"
> print(s)
hello"world
> print(string.quote(s))
"hello\"world"