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Étienne Reuh Fildadut
fe351b5ca4
Woke up and felt like changing a couple things. It's actually been worked on for a while, little at a time... The goal was to make the language and implementation much simpler. Well I don't know if it really ended up being simpler but it sure is more robust. Main changes: * proper first class functions and closures supports! proper scoping rules! no more namespace shenanigans! * everything is an expression, no more statements! make the implementation both simpler and more complex, but it's much more consistent now! the syntax has massively changed as a result though. * much more organized and easy to modify codebase: one file for each AST node, no more random fields or behavior set by some random node exceptionally, everything should now follow the same API defined in ast.abstract.Node Every foundational feature should be implemented right now. The vast majority of things that were possible in v2 are possible now; some things aren't, but that's usually because v2 is a bit more sane. The main missing things before a proper release are tests and documentation. There's a few other things that might be implemented later, see the ideas.md file.
62 lines
2.2 KiB
Lua
62 lines
2.2 KiB
Lua
local ast = require("ast")
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local Overload
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Overload = ast.abstract.Node {
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type = "overload",
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_evaluated = true,
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list = nil,
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init = function(self, ...)
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self.list = { ... }
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end,
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insert = function(self, val) -- only for construction
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table.insert(self.list, val)
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end,
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_format = function(self, ...)
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local s = "overload<"
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for i, e in ipairs(self.list) do
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s = s .. e:format(...)
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if i < #self.list then s = s .. ", " end
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end
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return s..">"
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end,
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traverse = function(self, fn, ...)
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for _, e in ipairs(self.list) do
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fn(e, ...)
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end
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end,
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call = function(self, state, args)
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local failure = {} -- list of failure messages (kept until we find the first success)
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local success, success_specificity, success_secondary_specificity = nil, -1, -1
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-- some might think that iterating a list for every function call is a terrible idea, but that list has a fixed number of elements, so big O notation says suck it up
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for _, fn in ipairs(self.list) do
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local specificity, secondary_specificity = fn:compatible_with_arguments(state, args)
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if specificity then
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if specificity > success_specificity then
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success, success_specificity, success_secondary_specificity = fn, specificity, secondary_specificity
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elseif specificity == success_specificity then
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if secondary_specificity > success_secondary_specificity then
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success, success_specificity, success_secondary_specificity = fn, specificity, secondary_specificity
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elseif secondary_specificity == success_secondary_specificity then
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error(("more than one function match %s, matching functions were at least (specificity %s.%s):\n\t• %s\n\t• %s"):format(args:format(state), specificity, secondary_specificity, fn:format_parameters(state), success:format_parameters(state)), 0)
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end
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end
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-- no need to add error message for less specific function since we already should have at least one success
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elseif not success then
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table.insert(failure, fn:format_parameters(state) .. ": " .. secondary_specificity)
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end
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end
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if success then
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return success:call_compatible(state, args)
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else
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-- error
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error(("no function match %s, possible functions were:\n\t• %s"):format(args:format(state), table.concat(failure, "\n\t• ")), 0)
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end
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end
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}
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return Overload
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