Arc Forum | There's a thread from over a year ago about table literal syntax for Arc that ha...

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1 point by evanrmurphy 5134 days ago | link | parent

There's a thread from over a year ago about table literal syntax for Arc that has helped me with some of my thinking here [1]. These are some examples of how object literal ssyntax might work in the JavaScript DSL, especially in the context of quotation:

  (= a 'foo)            a = 'foo';
  {a a}                 {a: a}  // => {a: 'foo'}
  {a 'a}                {a: 'a'}
  {'a 'a}               {'a': 'a'}
  '{a a}                '{a: a}'

  {a (- 5 4)}           {a: 5 - 4}
  {a '(- 5 4)}          {a: '5 - 4'}
  '{a (- 5 4)}          '{a: 5 - 4}'
  '{a '(- 5 4)}         '{a: \'5 - 4\'}'

And here are some array examples:

  [1 2 3]               [1, 2, 3]

  (= a 'foo)            a = 'foo';
  [a 2 3]               [a, 2, 3] // => ['foo', 2, 3]
  ['a 2 3]              ['a', 2, 3]
  '[a 2 3]              '[a, 2, 3]'
  '['a 2 3]             '[\'a\', 2, 3]'

I guess you could support quasi-quotation like this (though I don't know if you'd want to):

  (= a 'foo)            a = 'foo';
  `[,a 2 3]             '[' + a + ', 2, 3]'

But it will definitely work in the context of macros, where the quasi-quotation is transformed away before it hits JavaScript compilation:

  (mac array (x y z)
    `[,x ,y ,z])

  (array 1 2 3)

  ; expands to...
  
  [1 2 3]                [1, 2, 3]

Here's a much more flexible array macro:

  (mac array elts
    `[,@elts])

  (array 'foo 'bar 
         'baz 'quux)

  ; expands to...
  
  ['foo 'bar             ['foo', 'bar',
   'baz 'quux]            'baz', 'quux']

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[1] "hmm, how about '#table(a 1 b 2)' for a literal table syntax?": http://arclanguage.org/item?id=10678