From 2cd910389bb79036976508a93787404e2f2b2893 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89tienne=20Reuh=20Fildadut?= <fildadut@reuh.eu>
Date: Sat, 30 Dec 2023 23:43:05 +0100
Subject: [PATCH] Exported variables: no longer add export scope to every
 function, allow freely access and modifiy variable in function scope

Too many issues with predefining exported variables, and this is more flexible.
---
 anselme/ast/Closure.lua                       | 35 ++++++++-----------
 anselme/ast/Definition.lua                    | 20 ++++-------
 anselme/ast/Environment.lua                   |  2 +-
 anselme/ast/Function.lua                      |  9 ++---
 anselme/common/init.lua                       |  6 ++++
 anselme/state/State.lua                       | 10 +-----
 anselme/stdlib/closure.lua                    | 22 +++++++-----
 test/results/exported variable nested.ans     | 11 +++---
 test/results/function exported.ans            |  2 +-
 test/tests/exported variable nested.ans       |  6 ++--
 test/tests/exported variable.ans              |  3 +-
 test/tests/function exported.ans              |  5 ++-
 test/tests/function scope.ans                 |  3 +-
 ...amespace operator arbitrary expression.ans |  4 ++-
 14 files changed, 65 insertions(+), 73 deletions(-)

diff --git a/anselme/ast/Closure.lua b/anselme/ast/Closure.lua
index c1539eb..15772f9 100644
--- a/anselme/ast/Closure.lua
+++ b/anselme/ast/Closure.lua
@@ -2,7 +2,6 @@
 
 local ast = require("anselme.ast")
 local Overloadable, Runtime = ast.abstract.Overloadable, ast.abstract.Runtime
-local Definition
 
 local resume_manager
 
@@ -12,27 +11,14 @@ Closure = Runtime(Overloadable) {
 
 	func = nil, -- Function
 	scope = nil, -- Environment
-	exported_scope = nil, -- Environment
 
 	init = function(self, func, state)
 		self.func = func
+
+		-- layer a new scope layer on top of captured/current scope
+		-- to allow future define in the function (fn.:var = "foo")
+		state.scope:push()
 		self.scope = state.scope:capture()
-
-		-- layer a new export layer on top of captured/current scope
-		state.scope:push_export()
-		self.exported_scope = state.scope:capture()
-
-		-- pre-define exports
-		for _, target in pairs(self:list_resume_targets()) do
-			if Definition:is(target) and target.symbol.exported then
-				resume_manager:push_no_continue(state, target)
-				state.scope:push() -- create temp func scope, in case non-export definitions are done in the resume
-				self.func.expression:eval(state)
-				state.scope:pop()
-				resume_manager:pop(state)
-			end
-		end
-
 		state.scope:pop()
 	end,
 
@@ -43,7 +29,6 @@ Closure = Runtime(Overloadable) {
 	traverse = function(self, fn, ...)
 		fn(self.func, ...)
 		fn(self.scope, ...)
-		fn(self.exported_scope, ...)
 	end,
 
 	compatible_with_arguments = function(self, state, args)
@@ -53,15 +38,23 @@ Closure = Runtime(Overloadable) {
 		return self.func.parameters:format(state)
 	end,
 	call_dispatched = function(self, state, args)
-		state.scope:push(self.exported_scope)
+		state.scope:push(self.scope)
 		local exp = self.func:call_dispatched(state, args)
 		state.scope:pop()
 		return exp
 	end,
+	resume = function(self, state, target)
+		if self.func.parameters.min_arity > 0 then error("can't resume function with parameters") end
+		state.scope:push(self.scope)
+		resume_manager:push(state, target)
+		local exp = self.func:call(state, ast.ArgumentTuple:new())
+		resume_manager:pop(state)
+		state.scope:pop()
+		return exp
+	end,
 }
 
 package.loaded[...] = Closure
-Definition = ast.Definition
 resume_manager = require("anselme.state.resume_manager")
 
 return Closure
diff --git a/anselme/ast/Definition.lua b/anselme/ast/Definition.lua
index 3837564..593d420 100644
--- a/anselme/ast/Definition.lua
+++ b/anselme/ast/Definition.lua
@@ -3,7 +3,7 @@ local Nil, Overloadable
 
 local operator_priority = require("anselme.common").operator_priority
 
-local Definition = ast.abstract.ResumeTarget {
+local Definition = ast.abstract.Node {
 	type = "definition",
 
 	symbol = nil,
@@ -27,21 +27,13 @@ local Definition = ast.abstract.ResumeTarget {
 	end,
 
 	_eval = function(self, state)
-		if self.symbol.exported and state.scope:defined_in_current(self.symbol) then
-			return Nil:new() -- export vars: can reuse existing definition
-		end
-
 		local symbol = self.symbol:eval(state)
-		if symbol.alias then
-			state.scope:define_alias(symbol, self.expression)
-		else
-			local val = self.expression:eval(state)
+		local val = self.expression:eval(state)
 
-			if Overloadable:issub(val) then
-				state.scope:define_overloadable(symbol, val)
-			else
-				state.scope:define(symbol, val)
-			end
+		if Overloadable:issub(val) then
+			state.scope:define_overloadable(symbol, val)
+		else
+			state.scope:define(symbol, val)
 		end
 
 		return Nil:new()
diff --git a/anselme/ast/Environment.lua b/anselme/ast/Environment.lua
index 71e09c9..d039905 100644
--- a/anselme/ast/Environment.lua
+++ b/anselme/ast/Environment.lua
@@ -169,7 +169,7 @@ local Environment = ast.abstract.Runtime {
 		end
 		return false
 	end,
-	-- return bool if variable is defined in the current environment only - won't search in parent event for exported & partial names
+	-- return bool if variable is defined in the current environment only - won't search in parent env for exported & partial names
 	defined_in_current_strict = function(self, state, identifier)
 		return self.variables:has(state, identifier)
 	end,
diff --git a/anselme/ast/Function.lua b/anselme/ast/Function.lua
index d347f27..8abf701 100644
--- a/anselme/ast/Function.lua
+++ b/anselme/ast/Function.lua
@@ -13,10 +13,9 @@ Function = Overloadable {
 	parameters = nil, -- ParameterTuple
 	expression = nil,
 
-	init = function(self, parameters, expression, exports)
+	init = function(self, parameters, expression)
 		self.parameters = parameters
 		self.expression = ReturnBoundary:new(expression)
-		self.exports = exports or {}
 	end,
 
 	_format = function(self, ...)
@@ -33,10 +32,6 @@ Function = Overloadable {
 	traverse = function(self, fn, ...)
 		fn(self.parameters, ...)
 		fn(self.expression, ...)
-		for sym, val in pairs(self.exports) do
-			fn(sym, ...)
-			fn(val, ...)
-		end
 	end,
 
 	compatible_with_arguments = function(self, state, args)
@@ -61,7 +56,7 @@ Function = Overloadable {
 	end,
 
 	_eval = function(self, state)
-		return Closure:new(Function:new(self.parameters:eval(state), self.expression, self.exports), state)
+		return Closure:new(Function:new(self.parameters:eval(state), self.expression), state)
 	end,
 }
 
diff --git a/anselme/common/init.lua b/anselme/common/init.lua
index 2590212..97eb575 100644
--- a/anselme/common/init.lua
+++ b/anselme/common/init.lua
@@ -21,6 +21,12 @@ local common = {
 			:gsub("N", math.random(0x8, 0xb)) -- variant 1
 			:gsub("x", function() return ("%x"):format(math.random(0x0, 0xf)) end) -- random hexadecimal digit
 	end,
+	-- same as assert, but do not add position information
+	-- useful for errors raised from anselme (don't care about Lua error position)
+	assert0 = function(v, message, ...)
+		if not v then error(message, 0) end
+		return v, message, ...
+	end,
 	-- list of operators and their priority that are handled through regular function calls & can be overloaded/etc. by the user
 	regular_operators = {
 		prefixes = {
diff --git a/anselme/state/State.lua b/anselme/state/State.lua
index fb127f3..fe02233 100644
--- a/anselme/state/State.lua
+++ b/anselme/state/State.lua
@@ -10,17 +10,9 @@ local persistent_manager = require("anselme.state.persistent_manager")
 local uuid = require("anselme.common").uuid
 local parser = require("anselme.parser")
 local binser = require("anselme.lib.binser")
+local assert0 = require("anselme.common").assert0
 local anselme
 
--- same as assert, but do not add position information
--- useful for errors raised from anselme (don't care about Lua error position)
-local function assert0(v, message, ...)
-	if not v then
-		error(message, 0)
-	end
-	return v, message, ...
-end
-
 local State
 State = class {
 	type = "anselme state",
diff --git a/anselme/stdlib/closure.lua b/anselme/stdlib/closure.lua
index e6aab2f..4fe27ff 100644
--- a/anselme/stdlib/closure.lua
+++ b/anselme/stdlib/closure.lua
@@ -1,35 +1,41 @@
 local ast = require("anselme.ast")
-local Nil, Boolean, Definition = ast.Nil, ast.Boolean, ast.Definition
+local Nil, Boolean, Definition, Call, Function, ParameterTuple, FunctionParameter, Identifier, Overload = ast.Nil, ast.Boolean, ast.Definition, ast.Call, ast.Function, ast.ParameterTuple, ast.FunctionParameter, ast.Identifier, ast.Overload
+local assert0 = require("anselme.common").assert0
 
 return {
 	{
 		"defined", "(c::closure, s::string)",
 		function(state, c, s)
-			return Boolean:new(c.exported_scope:defined_in_current_strict(state, s:to_identifier()))
+			return Boolean:new(c.scope:defined_in_current_strict(state, s:to_identifier()))
+		end
+	},
+	{
+		"has upvalue", "(c::closure, s::string)",
+		function(state, c, s)
+			return Boolean:new(c.scope:defined(state, s:to_identifier()))
 		end
 	},
 	{
 		"_._", "(c::closure, s::string)",
 		function(state, c, s)
 			local identifier = s:to_identifier()
-			assert(c.exported_scope:defined_in_current_strict(state, identifier), ("no exported variable %q defined in closure"):format(s.string))
-			return c.exported_scope:get(state, identifier)
+			assert0(c.scope:defined(state, identifier), ("no variable %q defined in closure"):format(s.string))
+			return c.scope:get(state, identifier)
 		end
 	},
 	{
 		"_._", "(c::closure, s::string) = v",
 		function(state, c, s, v)
 			local identifier = s:to_identifier()
-			assert(c.exported_scope:defined_in_current_strict(state, identifier), ("no exported variable %q defined in closure"):format(s.string))
-			c.exported_scope:set(state, identifier, v)
+			assert0(c.scope:defined(state, identifier), ("no variable %q defined in closure"):format(s.string))
+			c.scope:set(state, identifier, v)
 			return Nil:new()
 		end
 	},
 	{
 		"_._", "(c::closure, s::symbol) = v",
 		function(state, c, s, v)
-			assert(s.exported, "can't define a non-exported variable from the outside of the closure")
-			state.scope:push(c.exported_scope)
+			state.scope:push(c.scope)
 			local r = Definition:new(s, v):eval(state)
 			state.scope:pop()
 			return r
diff --git a/test/results/exported variable nested.ans b/test/results/exported variable nested.ans
index 67821c7..bafafb6 100644
--- a/test/results/exported variable nested.ans	
+++ b/test/results/exported variable nested.ans	
@@ -1,11 +1,14 @@
 --# run #--
 --- text ---
+| {}"kk" |
+| {}"ko" |
+--- text ---
 | {}"" {}"42" {}"" |
 --- error ---
-./anselme/stdlib/closure.lua:15: no exported variable "y" defined in closure
-	↳ from test/tests/exported variable nested.ans:10:4 in call: f . "y"
-	↳ from test/tests/exported variable nested.ans:10:1 in text interpolation: | {f . "y"} |
-	↳ from test/tests/exported variable nested.ans:10:1 in translatable: | {f . "y"} |
+identifier "z" is undefined in branch 6843ee85-cea8-445d-10f21-9a8e54372094
+	↳ from test/tests/exported variable nested.ans:12:3 in identifier: z
+	↳ from test/tests/exported variable nested.ans:12:1 in text interpolation: | {z} |
+	↳ from test/tests/exported variable nested.ans:12:1 in translatable: | {z} |
 	↳ from ? in block: :f = ($() _)…
 --# saved #--
 {}
\ No newline at end of file
diff --git a/test/results/function exported.ans b/test/results/function exported.ans
index 8595571..dc8c9be 100644
--- a/test/results/function exported.ans	
+++ b/test/results/function exported.ans	
@@ -8,7 +8,7 @@
 --- text ---
 | {}"" {}"1" {}"" |
 --- text ---
-| {}"exported:" |
+| {}"upvalue:" |
 --- text ---
 | {}"" {}"1" {}"" |
 --- text ---
diff --git a/test/tests/exported variable nested.ans b/test/tests/exported variable nested.ans
index 165e2bb..313fe7b 100644
--- a/test/tests/exported variable nested.ans	
+++ b/test/tests/exported variable nested.ans	
@@ -5,6 +5,8 @@
 		:@z = 12
 	| ko
 
-|{f.x}
+f!
 
-|{f.y}
+|{x}
+
+|{z}
diff --git a/test/tests/exported variable.ans b/test/tests/exported variable.ans
index 12b0cb0..5fd2511 100644
--- a/test/tests/exported variable.ans	
+++ b/test/tests/exported variable.ans	
@@ -1,4 +1,5 @@
 :f = $
 	:@x = "ok"
+f!
 
-f.x
\ No newline at end of file
+x
\ No newline at end of file
diff --git a/test/tests/function exported.ans b/test/tests/function exported.ans
index 4f3dbe2..f25b052 100644
--- a/test/tests/function exported.ans	
+++ b/test/tests/function exported.ans	
@@ -6,11 +6,10 @@
 	a = a + 1
 
 :$ g
-	:@a = 1
-
 	|{a}
 
 	a = a + 1
+g.:a = 1
 
 |local:
 
@@ -20,7 +19,7 @@ f!
 
 f!
 
-|exported:
+|upvalue:
 
 g!
 
diff --git a/test/tests/function scope.ans b/test/tests/function scope.ans
index bb21a8b..b0951dd 100644
--- a/test/tests/function scope.ans	
+++ b/test/tests/function scope.ans	
@@ -1,4 +1,5 @@
+:b = 5
 :$ a
-	:@b = 5
+	:b = 12
 
 |a: {a.b}
diff --git a/test/tests/namespace operator arbitrary expression.ans b/test/tests/namespace operator arbitrary expression.ans
index 9b1a779..981a06b 100644
--- a/test/tests/namespace operator arbitrary expression.ans	
+++ b/test/tests/namespace operator arbitrary expression.ans	
@@ -1,5 +1,7 @@
 :$ f
-	:@x = 5
+	()
+
+f.:x = 5
 
 :a = f