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anselme/ast/Function.lua

78 lines
2.2 KiB
Lua

-- note: functions only appear in non-evaluated nodes! once evaluated, they always become closures
local ast = require("ast")
local Overloadable = ast.abstract.Overloadable
local Closure, ReturnBoundary
local operator_priority = require("common").operator_priority
local Function
Function = Overloadable {
type = "function",
parameters = nil, -- ParameterTuple
expression = nil,
format_priority = operator_priority["$_"],
exports = nil, -- { [sym] = exp, ... }, exctracted from expression during :prepare
init = function(self, parameters, expression, exports)
self.parameters = parameters
self.expression = ReturnBoundary:new(expression)
self.exports = exports or {}
end,
_format = function(self, ...)
if self.parameters.assignment then
return "$"..self.parameters:format(...).."; "..self.expression:format_right(...)
else
return "$"..self.parameters:format(...).." "..self.expression:format_right(...)
end
end,
traverse = function(self, fn, ...)
fn(self.parameters, ...)
fn(self.expression, ...)
end,
compatible_with_arguments = function(self, state, args)
return args:match_parameter_tuple(state, self.parameters)
end,
format_parameters = function(self, state)
return self.parameters:format(state)
end,
call_dispatched = function(self, state, args)
state.scope:push()
args:bind_parameter_tuple(state, self.parameters)
local exp = self.expression:eval(state)
state.scope:pop()
-- reminder: don't do any additionnal processing here as that won't be executed when resuming self.expression
-- instead wrap it in some additional node, like our friend ReturnBoundary
return exp
end,
_eval = function(self, state)
return Closure:new(Function:new(self.parameters:eval(state), self.expression, self.exports), state)
end,
_prepare = function(self, state)
state.scope:push_export() -- recreate scope context that will be created by closure
state.scope:push()
self.parameters:prepare(state)
self.expression:prepare(state)
state.scope:pop()
self.exports = state.scope:capture():list_exported(state)
state.scope:pop()
end,
}
package.loaded[...] = Function
Closure, ReturnBoundary = ast.Closure, ast.ReturnBoundary
return Function