From f160a00a1472485a3aadff2a73cc201c84e8a87c Mon Sep 17 00:00:00 2001
From: Case Duckworth
Date: Wed, 3 Apr 2024 23:34:19 -0500
Subject: Refactor literals reading and implement number literals

that is, #b, #o, #d, #x
---
 read.lua | 64 ++++++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 44 insertions(+), 20 deletions(-)

diff --git a/read.lua b/read.lua
index 6b223f8..4fb9b70 100644
--- a/read.lua
+++ b/read.lua
@@ -44,7 +44,6 @@ function m.inport (source, kind)
 					tok, toktype, self.line =
 						m.scan(self.line)()
 					if tok ~= nil then
-						print(tok, toktype)
 						return tok, toktype
 					end
 				end
@@ -96,6 +95,37 @@ local function consume_comment (cs)
 	return table.concat(comment), "comment", cs
 end
 
+local function idf (x)
+	return function () return x end
+end
+
+local function numf (base)
+	return function (token)
+		local n = tonumber(token:sub(3), base)
+		assert(n, "Can't read number: " .. token)
+		return n
+	end
+end
+
+local literals = {
+	literal = {
+		["#t"] = idf(true),
+		["#true"] = idf(true),
+		["#f"] = idf(false),
+		["#false"] = idf(false),
+		["#\\space"] = idf(t.character(" ")),
+		["#\\tab"] = idf(t.character("\t")),
+		["#\\newline"] = idf(t.character("\n")),
+	},
+	match = {
+		["^#b"] = numf(2),
+		["^#o"] = numf(8),
+		["^#d"] = numf(10),
+		["^#x"] = numf(16),
+		["^#\\"] = function (tok) return t.character(tok:sub(3)) end,
+	}
+}
+
 local function consume_literal (cs)
 	-- whitespace and parantheses character literals.
 	-- reverse the match test b/c it's already a complement
@@ -105,26 +135,20 @@ local function consume_literal (cs)
 	pop(cs) -- discard '#'
 	local token, value, cs = consume_token(cs) -- todo: vectors #(...)
 	token = "#" .. token -- put '#' back
-	-- tokens!
-	if token == "#t" or token == "#true" then -- booleans
-		value = true
-	elseif token == "#f" or token == "#false" then
-		value = false
-		--[[ To actually *read* nil, I need to change ports from
-			returning `nil' on eof to an `eof' symbol, i think.
-
-			elseif token == "#n" or token == "#nil" then
-			value = nil
-		--]]
-	elseif token == "#\\space" then -- characters
-		value = type.character(" ")
-	elseif token == "#\\newline" then
-		value = type.character("\n")
-	elseif token:match("^#\\") then
-		value = type.character(token:sub(3))
+
+	if literals.literal[token] then
+		value = literals.literal[token]()
 	else
-		error("Bad literal notation: " .. token)
+		for re, fn in pairs(literals.match) do
+			if token:match(re) then
+				value = fn(token)
+			end
+		end
 	end
+	-- TODO : if `nil' is to be a value in lam i'm going to have to figure
+	-- out some kind of 'lam nil' and 'lua nil' or something..
+	assert(value~=nil, "Can't read literal: " .. token)
+
 	return value, "literal", cs
 end
 
@@ -208,7 +232,7 @@ m.readmacros = {
 			table.insert(Q, m.read(port))
 			return t.list(Q)
 		end,
-	comment = function () return nil end,
+	comment = idf(nil),
 }
 
 function m.read (port)
-- 
cgit 1.4.1-21-gabe81