local truthy, anselme, compare, is_of_type

local functions
functions = {
	-- discard left
	[";(a, b)"] = {
		mode = "raw",
		value = function(a, b) return b end
	},
	-- comparaison
	["==(a, b)"] = {
		mode = "raw",
		value = function(a, b)
			return {
				type = "number",
				value = compare(a, b) and 1 or 0
			}
		end
	},
	["!=(a, b)"] = {
		mode = "raw",
		value = function(a, b)
			return {
				type = "number",
				value = compare(a, b) and 0 or 1
			}
		end
	},
	[">(a::number, b::number)"] = function(a, b) return a > b end,
	["<(a::number, b::number)"] = function(a, b) return a < b end,
	[">=(a::number, b::number)"] = function(a, b) return a >= b end,
	["<=(a::number, b::number)"] = function(a, b) return a <= b end,
	-- arithmetic
	["+(a::number, b::number)"] = function(a, b) return a + b end,
	["+(a::string, b::string)"] = function(a, b) return a .. b end,
	["-(a::number, b::number)"] = function(a, b) return a - b end,
	["-(a::number)"] = function(a) return -a end,
	["*(a::number, b::number)"] = function(a, b) return a * b end,
	["/(a::number, b::number)"] = function(a, b) return a / b end,
	["//(a::number, b::number)"] = function(a, b) return math.floor(a / b) end,
	["^(a::number, b::number)"] = function(a, b) return a ^ b end,
	-- boolean
	["!(a)"] = {
		mode = "raw",
		value = function(a)
			return {
				type = "number",
				value = truthy(a) and 0 or 1
			}
		end
	},
	-- pair
	[":(a, b)"] = {
		mode = "raw",
		value = function(a, b)
			return {
				type = "pair",
				value = { a, b }
			}
		end
	},
	-- type
	["::(a, b)"] = {
		mode = "raw",
		value = function(a, b)
			return {
				type = "type",
				value = { a, b }
			}
		end
	},
	-- index
	["()(l::list, i::number)"] = {
		mode = "untyped raw",
		value = function(l, i)
			return l.value[i.value] or { type = "nil", value = nil }
		end
	},
	["()(l::list, i::string)"] = {
		mode = "untyped raw",
		value = function(l, i)
			for _, v in ipairs(l.value) do
				if v.type == "pair" and compare(v.value[1], i) then
					return v.value[2]
				end
			end
			return { type = "nil", value = nil }
		end
	},
	-- index assignment
	["()(l::list, i::number) := v"] = {
		mode = "raw",
		value = function(l, i, v)
			local lv = l.type == "type" and l.value[1] or l
			local iv = i.type == "type" and i.value[1] or i
			lv.value[iv.value] = v
			return v
		end
	},
	["()(l::list, k::string) := v"] = {
		mode = "raw",
		value = function(l, k, v)
			local lv = l.type == "type" and l.value[1] or l
			local kv = k.type == "type" and k.value[1] or k
			-- update index
			for _, x in ipairs(lv.value) do
				if x.type == "pair" and compare(x.value[1], kv) then
					x.value[2] = v
					return v
				end
			end
			-- new index
			table.insert(lv.value, {
				type = "pair",
				value = { kv, v }
			})
			return v
		end
	},
	-- pair methods
	["name(p::pair)"] = {
		mode = "untyped raw",
		value = function(a)
			return a.value[1]
		end
	},
	["value(p::pair)"] = {
		mode = "untyped raw",
		value = function(a)
			return a.value[2]
		end
	},
	-- list methods
	["len(l::list)"] = {
		mode = "untyped raw", -- raw to count pairs in the list
		value = function(a)
			return {
				type = "number",
				value = #a.value
			}
		end
	},
	["insert(l::list, v)"] = {
		mode = "raw",
		value = function(l, v)
			local lv = l.type == "type" and l.value[1] or l
			table.insert(lv.value, v)
		end
	},
	["insert(l::list, i::number, v)"] = {
		mode = "raw",
		value = function(l, i, v)
			local lv = l.type == "type" and l.value[1] or l
			local iv = i.type == "type" and i.value[1] or i
			table.insert(lv.value, iv.value, v)
		end
	},
	["remove(l::list)"] = {
		mode = "untyped raw",
		value = function(l)
			return table.remove(l.value)
		end
	},
	["remove(l::list, i::number)"] = {
		mode = "untyped raw",
		value = function(l, i)
			return table.remove(l.value, i.value)
		end
	},
	["find(l::list, v)"] = {
		mode = "raw",
		value = function(l, v)
			local lv = l.type == "type" and l.value[1] or l
			for i, x in ipairs(lv.value) do
				if compare(x, v) then
					return i
				end
			end
			return { type = "number", value = 0 }
		end
	},
	-- other methods
	["error(m::string)"] = function(m) error(m, 0) end,
	["rand"] = function() return math.random() end,
	["rand(a::number)"] = function(a) return math.random(a) end,
	["rand(a::number, b::number)"] = function(a, b) return math.random(a, b) end,
	["raw(v)"] = {
		mode = "raw",
		value = function(v)
			if v.type == "type" then
				return v.value[1]
			else
				return v
			end
		end
	},
	["type(v)"] = {
		mode = "raw",
		value = function(v)
			if v.type == "type" then
				return v.value[2]
			else
				return {
					type = "string",
					value = v.type
				}
			end
		end
	},
	["is of type(v, t)"] = {
		mode = "raw",
		value = function(v, t)
			return {
				type = "number",
				value = is_of_type(v, t) or 0
			}
		end
	},
	["cycle(l...)"] = function(l)
		local f, fseen = l[1], assert(anselme.running:eval(l[1]..".👁️", anselme.running:current_namespace()))
		for j=2, #l do
			local seen = assert(anselme.running:eval(l[j]..".👁️", anselme.running:current_namespace()))
			if seen < fseen then
				f = l[j]
				break
			end
		end
		return anselme.running:run(f, anselme.running:current_namespace())
	end,
	["random(l...)"] = function(l)
		return anselme.running:run(l[math.random(1, #l)], anselme.running:current_namespace())
	end,
	["next(l...)"] = function(l)
		local f = l[#l]
		for j=1, #l-1 do
			local seen = assert(anselme.running:eval(l[j]..".👁️", anselme.running:current_namespace()))
			if seen == 0 then
				f = l[j]
				break
			end
		end
		return anselme.running:run(f, anselme.running:current_namespace())
	end
}

package.loaded[...] = functions
local common = require((...):gsub("stdlib%.functions$", "interpreter.common"))
truthy, compare, is_of_type = common.truthy, common.compare, common.is_of_type
anselme = require((...):gsub("stdlib%.functions$", "anselme"))