Initial commit

etype.lua

@@ -0,0 +1,80 @@
+local EType = {}
+EType.__index = EType
+
+function EType:__eq(other)
+	for k, v in pairs(self) do
+		if rawget(other, k) ~= v then
+			return false
+		end
+	end
+	for k, v in pairs(other) do
+		if rawget(self, k) ~= v then
+			return false
+		end
+	end
+	return true
+end
+
+function EType:__tostring()
+	if self.kind == "scalar" then
+		return (self.unsigned and "u" or "i") .. self.bits
+	elseif self.kind == "func" then
+		return (tostring(self.input) .. "->" .. tostring(self.output))
+	elseif self.kind == "struct" then
+		return ("(" .. table.concat(self.fields, ",") .. ")")
+	elseif self.kind == "pointer" then
+		return tostring(self.to) .. "*"
+	elseif self.kind == "array" then
+		return tostring(self.element_etype) .. "[" .. (self.length or "?") .. "]"
+	elseif self.kind == "string" then
+		return "string"
+	end
+	error("Unimplemented " .. self.kind)
+end
+
+function EType:byte_size()
+	if self.kind == "scalar" then
+		return (self.bits + 7) // 8
+	end
+	error("Unimplemented " .. self.kind)
+end
+
+local ETypes = {}
+
+function ETypes.scalar(unsigned, bits)
+	return setmetatable({kind = "scalar", bits = bits, unsigned = unsigned}, EType)
+end
+
+function ETypes.func(input_etype, output_etype)
+	assert(input_etype ~= nil, "Nil function input")
+	assert(output_etype ~= nil, "Nil function output")
+	return setmetatable({kind = "func", input = input_etype, output = output_etype, modifiers = {}}, EType)
+end
+
+function ETypes.array(element_etype, length)
+	return setmetatable({kind = "array", element_etype = element_etype, length = length}, EType)
+end
+
+function ETypes.struct(fields)
+	return setmetatable({kind = "struct", fields = fields, modifiers = {}}, EType)
+end
+
+function ETypes.string()
+	return setmetatable({kind = "string"}, EType)
+end
+
+function ETypes.ref(child)
+	assert(child, "Nil pointee type")
+	return setmetatable({kind = "pointer", to = child}, EType)
+end
+
+function ETypes.deref(ptr)
+	assert(ptr and ptr.kind == "pointer", "Non-pointer type")
+	return ptr.to
+end
+
+function ETypes.is(etype)
+	return type(etype) == "table" and getmetatable(etype) == EType
+end
+
+return ETypes