Look at "structure" #82
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skx
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Nov 12, 2022
This pull-request contains a proof of concept "struct" implementation, which currently allows structures to be defined - as a list of fields, and objects created assuming all fields are present. This will close #82, once complete. Sample usage: ;; define a structure (struct person name address) ;; create an instance (set! self (person "Steve Kemp" "My home address, Helsinki, Finland")) (print "struct.type is %s" (type self)) (print "struct.address contains:%s" (get self "address")) (print "struct.name contains:%s" (get self "name")) Here you'll notice that the struct is actually a hash, and we're merely setting the named fields as key/val pairs. This is pretty smart, all we've really done is recorded the fields a structure should contain, and hooked into our execution to instantiate a new hash when we see a named structure - before falling back to invoking a command instead. The bit that's missing? We want to have "type?" support, and we want to have accessors created. type? support is trivial if we copy/paste primitive.Hash into primitive.Struct and add a "type" member. We just return: struct-%s, primitive.Type However adding accessors get's tricky. I could have another map but getting type validaiton is gonna be a pain. It also seems like if I continue to abuse/reuse the Hash type we could use something siumilar to allow: hash.field To either get/set values and that feels like a useful piece of syntatic sugar. Will experiment before committing.
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Hacker news had a link to Zuo recently:
That has support for "struct", which seems to do a bunch of things. Given the following code:
Generates a bunch of things:
(set! person (fn* (name age))(set! person-name (fn* (strct) (return strct.name)(set! person-age (fn* (strct) (return strct.age)More stuff wasn't immediately obvious, but I guess there are setters to match the getters. I guess the complication for implementation would be the creation of the methods, dynamically.
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