Hello Nicolas, Monday, October 16, 2006, 6:31:42 PM, you wrote:
What if operator precedences were specified as a partial order instead of using numbers?
precInherit <*> -> @*@ precAll ?+? > ?*?
Regarding precAll: I'm not a regular expressions/glob for semantics fan, but you get the idea.
The idea is to define a partial order on operators and let undecided operator relationships remain undefined. Composition remains an open issue, but perhaps someone else will have a light bulb about that.
well, it is what typically done when you define expression parsers by hand (for any language that had fixed precedences). smth like this: expr1 ::= expr2 | expr1 + expr2 | expr1 - expr2 expr2 ::= expr3 | expr2 * expr3 | expr2 / expr3 expr3 ::= ... but when you want to have user-defined operators, that will mean that you need either to define precedences to all other operators (including those from other libs), or sometimes user programs will not compile because they used combination of operators with undefined precedence good for making good headache :) -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com