A

On 28 April 2018 at 20:21, Peter Uhn��k <i.uhnak@gmail.com> wrote:

What would entail actually extending the syntax and adding the set literal?

From my brief observations (when I was discussing this with OP on discord):

* adding a new AST node
* extend RBParser
* extend IRMethod/IRTranslator... maybe generating bytecode for `{ ... } asSet` instead would be enough? (not sure how debugger would react to this)

anything else? Would VM changes be required?

��I added

��������� '{' binarySelector expr '.' ... '.' expr ['.'] '}'

to my ���compiler because I was sick of other people being

able to write stuff more elegantly in Python than I could

in Smalltalk.�� Here the binarySelector controls what kind

of set:

��=������ Set

��==���� IdentitySet

��?=���� CaseInsensitiveSet

��<������ SortedSet (splay trees)

��>������ SortedSet (with comparison reversed)

��<>���� TernarySet (ternary search string for strings).

I'm not happy with the syntax, but it's the least ugly I've

been able to find.�� Having syntax only for Set would be so

limiting there'd be no real point.

So.�� No change to the scanner.

No change to the abstract syntax trees.

{== x. y}

generates the same syntax tree that

((IdentitySet new: 2) add: x; add: y; yourself)

would have done.

And therefore no change to the back end code

generator.

The *only* change was the parsing routine that

responds to '{'.

The fundamental issue is WHY you want an extension

to the syntax.�� In my case, the {binarySelector exprs}

syntax for sets and corresponding #{binarySelector maplets}

syntax for dictionaries were to let me approximate the

brevity of Python and Javascript.�� I didn't need new

*semantics*.

In contrast, the ##(expr) syntax in Dolphin, Smalltalk/X,

and whatever others does NOT offer brevity at all but

DOES offer new semantics.�� To the limited, not to say

derisory, extent to which I understand the Dolphin compiler,

it does have a special StOptimizedNode type of AST node

for ##(...) forms.�� I don't *think* any VM changes are

needed, unless of course you want to be able to decompile

the byte-code and recover the ##(expr) source.�� I don't

have a Windows box any more, so I can't run Dolphin,

sorry, just admire it.�� I can say that it takes care not

to put literals inside a ##(expr) form in the literal

table.