From 9c5643d5f78e4228d47e293b421d7f388d47945f Mon Sep 17 00:00:00 2001
From: Case Duckworth
Date: Tue, 19 Mar 2024 22:13:44 -0500
Subject: A new start!

---
 Makefile  | 19 ++++++++++---------
 README.md |  6 ++++++
 base.lua  | 37 +++++++++++++++++++++++++++++++++++++
 eval.lua  | 39 ++++++---------------------------------
 read.lua  |  2 +-
 repl.lua  | 21 +++++++++++++++++++++
 test.lua  | 43 +++++++++++++++++++++++++++----------------
 type.lua  |  1 +
 8 files changed, 109 insertions(+), 59 deletions(-)
 create mode 100644 base.lua
 create mode 100644 repl.lua

diff --git a/Makefile b/Makefile
index 54c4f2c..f08ae06 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,12 @@
-LUA ?= rlwrap luajit
+LUA ?= rlwrap luajit \
+	-e 'pp = require "pp"' \
+	-e 'eval = require "eval"' \
+	-e 'read = require "read"' \
+	-e 'type = require "type"' \
+	-e 'utf8 = require "utf8"' \
+	-e 'util = require "util"' \
+	-e 'test = require "test"'
+
 
 .PHONY: repl
 repl:
@@ -6,14 +14,7 @@ repl:
 
 .PHONY: test
 test:
-	$(LUA) -i \
-		-e 'pp = require "pp"' \
-		-e 'eval = require "eval"' \
-		-e 'read = require "read"' \
-		-e 'type = require "type"' \
-		-e 'utf8 = require "utf8"' \
-		-e 'util = require "util"' \
-		-e 'test = require "test"'
+	$(LUA) -e 'test.runtests()'
 
 .PHONY: check
 check:
diff --git a/README.md b/README.md
index 3728ba6..1dcd392 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,12 @@ see COPYING for details.
 
 [email me]: mailto:acdw@acdw.net
 
+## references
+
+- [Lua 5.1 reference](https://www.lua.org/manual/5.1/manual.html)
+- [Luajit](https://luajit.org/)
+- [R7RS](https://standards.scheme.org/corrected-r7rs/r7rs.html)
+
 ## thanks
 
 thanks to peter norvig's [series on lisp interpreters][norvig]
diff --git a/base.lua b/base.lua
new file mode 100644
index 0000000..9c5b5b7
--- /dev/null
+++ b/base.lua
@@ -0,0 +1,37 @@
+--- lam.base --- base environment
+
+local base = {}
+local type = require "type"
+local isNull = type.isNull
+
+base.env = {
+	begin =
+		function (r)
+			local r = r
+			while not isNull(r.cdr) do
+				r = r.cdr
+			end
+			return r.car
+		end,
+	["+"] =
+		function (r)
+			local r, a = r, 0
+			while r.cdr do
+				r, a = r.cdr, a + r.car
+			end
+			return a
+		end,
+	["-"] =
+		function (r)
+			if isNull(r) then return -1 end
+			if isNull(r.cdr) then return (- r.car) end
+			local r, a = r.cdr, r.car
+			while r.cdr do
+				r, a = r.cdr, a - r.car
+			end
+			return a
+		end,
+}
+
+---
+return base
diff --git a/eval.lua b/eval.lua
index 5e897e2..e926bc4 100644
--- a/eval.lua
+++ b/eval.lua
@@ -1,6 +1,7 @@
 --- lam.eval
 
 local eval = {}
+local base = require "base"
 local type = require "type"
 local isNull, isList, isa, List, Cons =
 	type.isNull, type.isList, type.isa, type.List, type.Cons
@@ -30,6 +31,7 @@ function eval.Proc (params, body, env)
 					inner[p.car] = a.car
 					p, a = p.cdr, a.cdr
 				end
+				pp.pp(self.body)
 				return eval.eval(
 					self.body,
 					eval.Env(inner, self.env))
@@ -38,37 +40,8 @@ function eval.Proc (params, body, env)
 	return setmetatable(v, mt)
 end
 
-local global = {
-	begin =
-		function (r)
-			local r = r
-			while not isNull(r.cdr) do
-				r = r.cdr
-			end
-			return r.car
-		end,
-	["+"] =
-		function (r)
-			local r, a = r, 0
-			while r.cdr do
-				r, a = r.cdr, a + r.car
-			end
-			return a
-		end,
-	["-"] =
-		function (r)
-			if isNull(r) then return -1 end
-			if isNull(r.cdr) then return (- r.car) end
-			local r, a = r.cdr, r.car
-			while r.cdr do
-				r, a = r.cdr, a - r.car
-			end
-			return a
-		end,
-}
-
 function eval.eval (x, env)
-	env = env or global
+	env = env or base.env
 	if isa(x, "Symbol") then
 		return env[x]
 	elseif not isList(x) then
@@ -77,13 +50,13 @@ function eval.eval (x, env)
 		local op, args = x.car, x.cdr
 		if op == "quote" then
 			return args.car
-		elseif op == "define" then
+		elseif op == "define" or op == "def" then
 			env[args.car] = eval.eval(args.cdr.car, env)
 			return nil
-		elseif op == "lambda" then
+		elseif op == "lambda" or op == "lam" then
 			return eval.Proc(
 				args.car,
-				Cons("begin", args.cdr),
+				Cons("begin", args.cdr), -- i don't like this
 				env)
 		elseif op == "if" then
 			assert(not isNull(args.cdr), "Malformed 'if'")
diff --git a/read.lua b/read.lua
index c5dacc0..d21e4cb 100644
--- a/read.lua
+++ b/read.lua
@@ -7,7 +7,7 @@ local util = require "util"
 local pop = util.pop
 local unpack = table.unpack or unpack
 
-function program_characters (program)
+local function program_characters (program)
 	local chars = {}
 	for pos, code in utf8.codes(program) do
 		table.insert(chars, code)
diff --git a/repl.lua b/repl.lua
new file mode 100644
index 0000000..34e4c94
--- /dev/null
+++ b/repl.lua
@@ -0,0 +1,21 @@
+--- lam.repl
+
+local repl = {}
+local eval = require("eval").eval
+local read = require("read").read
+
+function repl.repl (prompt)
+	if not prompt then prompt = "lam> " end
+	io.input():setvbuf("line")
+	repeat
+		io.write(prompt)
+		io.output():flush()
+		local input = io.read()
+		if input == nil then break end
+		local value = eval(read(input))
+		if value then print(value) end
+	until false
+end
+
+---
+return repl
diff --git a/test.lua b/test.lua
index ce8c034..1d90df2 100644
--- a/test.lua
+++ b/test.lua
@@ -1,28 +1,39 @@
 --- lam.test
--- testing helpers
 
 local test = {}
 local eval = require("eval").eval
 local read = require("read").read
+local luatype = require("type").luatype
 
-function test.lambda ()
-	local ls = {
-		[ [[((lambda (x) (+ x x)) 3)]] ] = 6,
-		[ [[((lambda () 100))]] ] = 100,
-		[ [[((lambda (x) 1 2 3) 4)]] ] = 3,
-		[ [[((lambda () 1 2 3))]] ] = 3,
-		[ [[((lambda (x) x (+ x x) (+ x x x)) 9)]] ] = 27,
-	}
-	for l, target in pairs(ls) do
-		io.write(string.format("%s == %s\n\t", l, target))
-		local value = eval(read(l))
-		if value == target then
-			print "ok"
-		else
-			print(string.format("not ok : %s", value))
+function test.test (form, expected)
+	local diag = string.format("%s == %s", form, expected)
+	local value = eval(read(form))
+	if value == expected then
+		print(string.format("ok: %s", diag))
+	else
+		print(string.format("not ok: %s != %s", diag, value))
+	end
+end
+
+function test.runtests ()
+	for name, fn in pairs(test) do
+		if luatype(fn) == "function"
+			and name ~= "test"
+			and name ~= "runtests"
+		then
+			print(">>>", name)
+			fn()
 		end
 	end
 end
 
+function test.lambda ()
+	test.test([[((lambda (x) (+ x x)) 3)]], 6)
+	test.test([[((lambda () 100))]], 100)
+	test.test([[((lambda (x) 1 2 3) 4)]], 3)
+	test.test([[((lambda () 1 2 3))]], 3)
+	test.test([[((lambda (x) x (+ x x) (+ x x x)) 9)]], 27)
+end
+
 ---
 return test
diff --git a/type.lua b/type.lua
index 945f4d1..0d3b776 100644
--- a/type.lua
+++ b/type.lua
@@ -31,6 +31,7 @@ end
 -- Symbols and Numbers are strings and numbers, respectively.  At some point
 -- I'll want to implement a full numeric tower and symbol tables or namespaces
 -- or whatever, but today is not that day
+
 t.Symbol = tostring
 t.Number = tonumber
 
-- 
cgit 1.4.1-21-gabe81