Would the new private syntax then go from
(old syntax)
class Monster {
// The contextual keyword "constructor" followed by an argument
// list and a body defines the body of the class’s constructor
// function. public and private declarations in the constructor
// declare and initialize per-instance properties. Assignments
// such as "this.foo = bar;" also set public properties.
constructor(name, health) {
public name = name;
private health = health;
}
// An identifier followed by an argument list and body defines a
// method. A “method” here is simply a function property on some
// object.
attack(target) {
log('The monster attacks ' + target);
}
// The contextual keyword "get" followed by an identifier and
// a curly body defines a getter in the same way that "get"
// defines one in an object literal.
get isAlive() {
return private(this).health > 0;
}
// Likewise, "set" can be used to define setters.
set health(value) {
if (value < 0) {
throw new Error('Health must be non-negative.')
}
private(this).health = value
}
// After a "public" modifier,
// an identifier optionally followed by "=" and an expression
// declares a prototype property and initializes it to the value
// of that expression.
public numAttacks = 0;
// After a "public" modifier,
// the keyword "const" followed by an identifier and an
// initializer declares a constant prototype property.
public const attackMessage = 'The monster hits you!';
}
to:
class Monster {
// The contextual keyword "constructor" followed by an argument
// list and a body defines the body of the class’s constructor
// function. public and private declarations in the constructor
// declare and initialize per-instance properties. Assignments
// such as "this.foo = bar;" also set public properties.
constructor(name, healthvalue) {
public name = name;
module name from "@name";
private health = name.create();
this[health] = healthvalue;
}
// An identifier followed by an argument list and body defines a
// method. A “method” here is simply a function property on some
// object.
attack(target) {
log('The monster attacks ' + target);
}
// The contextual keyword "get" followed by an identifier and
// a curly body defines a getter in the same way that "get"
// defines one in an object literal.
get isAlive() {
return this[health] > 0;
}
// Likewise, "set" can be used to define setters.
set health(value) {
if (value < 0) {
throw new Error('Health must be non-negative.')
}
this[health] = value
}
// After a "public" modifier,
// an identifier optionally followed by "=" and an expression
// declares a prototype property and initializes it to the value
// of that expression.
public numAttacks = 0;
// After a "public" modifier,
// the keyword "const" followed by an identifier and an
// initializer declares a constant prototype property.
public const attackMessage = 'The monster hits you!';
}
?
If so it seems odd, privately named variables like health, although declared in
the constructor are implicitly available throughout the class.
________________________________
From: Mark S. Miller <[email protected]>
To: Brendan Eich <[email protected]>
Cc: Kam Kasravi <[email protected]>; Axel Rauschmayer <[email protected]>;
es-discuss <[email protected]>
Sent: Sunday, September 25, 2011 2:37 PM
Subject: Re: Class literals: does "public" still make sense?
On Sun, Sep 25, 2011 at 2:08 PM, Brendan Eich <[email protected]> wrote:
On Sep 25, 2011, at 1:04 PM, Kam Kasravi wrote:
>
>If the intent of classes is to provide a declarative syntax for its 'shape'
>then dropping the private syntax in lieu of private name objects seems to run
>counter to this philosophy.
>
>We did not agree to drop the private declaration syntax at the July TC39
>meeting. Perhaps my understanding of our agreement then does not match Marks?
It matches.
>
>What we agreed to drop was the private(this) straw syntax in the classes
>proposal, in favor of this[x], this[y], for private-declared private name
>objects x and y.
We definitely agreed to drop private(this) and private(other), as these were
only ever placeholders for a needed syntax anyway. My own experience trying to
use them is that they are unbearably verbose. We agreed to use the this[x]
syntax *provided* it works out, depending on the price syntax and semantics of
private names. Btw, I am optimistic it will work out. I just want to keep that
qualifier on the table ;).
--
Cheers,
--MarkM_______________________________________________
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