From bbaff0e0c204c2fab216f6501dc8c11b4425b4bc Mon Sep 17 00:00:00 2001
From: Case Duckworth
Date: Mon, 4 Mar 2024 21:01:27 -0600
Subject: Ugghhhh totally not working

---
 types.lua | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 103 insertions(+), 19 deletions(-)

(limited to 'types.lua')

diff --git a/types.lua b/types.lua
index d4c8d14..e4813b2 100644
--- a/types.lua
+++ b/types.lua
@@ -1,28 +1,112 @@
 --- lam.types
 
 local types = {}
+local util = require "util"
+table.unpack = table.unpack or unpack
 
-types.luatype = type
-
-function types.lamtype (x)
-	if types.luatype(x) == "string" then
-		return "symbol"
-	elseif types.luatype(x) == "number" then
-		return "number"
-	elseif getmetatable(x) and getmetatable(x).__type then
-		return getmetatable(x).__type
-	elseif types.luatype(x) == "table" then
-		return "list"
-	else
-		return types.luatype(x)
+--- Converting between types
+
+types.globalns = {}		-- namespace
+
+types.Symbol =
+	function (name, ns, aliases)
+		ns = ns or types.globalns
+		aliases = aliases or {}
+		if ns[name] then return ns[name] end
+		local sym = { name = name, aliases = aliases }
+		ns[name] = sym
+		for _,a in ipairs(aliases) do
+			ns[a] = sym
+		end
+		local mt = {
+			__type = "Symbol",
+			__tostring = function (self) return self.name end,
+		}
+		return setmetatable(sym, mt)
+	end
+
+types.Number = tonumber
+
+types.String =
+	function (str)
+		local s = {
+			value = str,
+			escape =
+				function(self)
+					return self:gsub("\"", "\\\"")
+				end,
+		}
+		local mt = {
+			__type = "String",
+			__tostring =
+				function (self)
+					return string.format(
+						"\"%s\"",
+						self:escape())
+				end,
+		}
+		return setmetatable(s, mt)
+	end
+
+types.Cons =
+	function (a, b)
+		assert(a ~= nil and b ~= nil,
+			"Need two non-nil arguments in a pair")
+		local s = { a, b }
+		local mt = {
+			__type = "Pair",
+			__tostring =
+				function (p)
+					local out = {}
+					local car, cdr = p[1], p[2]
+					while cdr do
+						table.insert(out, tostring(car))
+						if type(cdr) == "table" then
+							car = cdr[1]
+							cdr = cdr[2]
+						else
+							table.insert(out, ".")
+							table.insert(out, cdr)
+							break
+						end
+					end
+					return "("..table.concat(out, " ")..")"
+				end
+
+		}
+		return setmetatable(s, mt)
 	end
-end
 
-types["number?"] = function (x) return types.lamtype(x) == "number" end
-types["symbol?"] = function (x) return types.lamtype(x) == "symbol" end
-types["list?"] = function (x) return types.lamtype(x) == "list" end
-types["procedure?"] = function (x) return types.lamtype(x) == "procedure" end
-types["null?"] = function (x) return x == {} end
+types.List =
+	function (tbl)
+		local function tolist(base, items)
+			if #items == 0 then return base end
+			return tolist(
+				types.Cons(table.remove(items), base),
+				items)
+		end
+		return tolist({}, tbl)
+	end
+
+--- Determining types
+
+types.lamtype =
+	function (x)
+		if type(x) == "number" then
+			return "Number"
+		elseif getmetatable(x) and getmetatable(x).__type then
+			return getmetatable(x).__type
+		else
+			return type(x)
+		end
+	end
+
+--- Type predicates
+
+types.isa =
+	function (x, t)
+		return types.lamtype(x) == t
+	end
 
 ---
 return types
-- 
cgit 1.4.1-21-gabe81