Smalltalk-style syntax

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Revision as of 02:03, 24 October 2007 by Kevin Reid (Talk | contribs)
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User:Kevin Reid's idle speculation on an alternate surface syntax for E.

Translated mint example:

makeMint does {
  run: name = the any {
    [sealer, unsealer] = makeBrandPair run: name.
    mint does {
        __printOn: out = the void {
            out print: `<$name's mint>`.
        }
 
        makePurse: var balance an (int >= 0) = the any {
            decr does {
                run: amount an (0..balance) = the void {
                    set balance = balance - amount.
                }
            }.
            purse does {
                __printOn: out = the void {
                    out print: `<has $balance $name bucks>`.
                }
                getBalance = the int { balance }
                sprout     = the any { mint makePurse: 0 }
                getDecr    = the any { sealer seal: decr }

                deposit: amount an int  from: src = the void {
                    (unsealer unseal: src getDecr) run: amount.
                    set balance = balance + amount.
                }
            }.
            ^ purse
        }
    }.
    ^ mint
  }
}

Verb mapping

Syntax Verb Arity
recip verb "verb" 0
recip verb: arg "verb" 1
recip verb: arg and: arg "verb:and" 2

The traditional Smalltalk/ObjC form would include the colon in the 1-arg verb, but this would drop it for compatibility with normal E protocols.

There would also need to be a way to use arbitrary verbs as normal E surface syntax provides (the "verb-string" syntax).

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