Undefine _ in attached block

anselme/ast/Environment.lua

@@ -68,6 +68,7 @@ local Environment = ast.abstract.Runtime {
 	variables = nil, -- Table of { {identifier} = variable metadata, ... }
 
 	partial = nil, -- { [name string] = true, ... }
+	undefine = nil, -- { [name string] = true, ... }
 	export = nil, -- bool
 
 	init = function(self, state, parent, partial_names, is_export)
@@ -75,6 +76,7 @@ local Environment = ast.abstract.Runtime {
 		self.parent = parent
 		self.partial = partial_names
 		self.export = is_export
+		self.undefine = {}
 	end,
 
 	traverse = function(self, fn, ...)
@@ -97,7 +99,11 @@ local Environment = ast.abstract.Runtime {
 			or (self.export ~= symbol.exported) then
 			return self.parent:define(state, symbol, exp)
 		end
-		self.variables:set(state, symbol:to_identifier(), VariableMetadata:new(state, symbol, exp))
+		if symbol.undefine then
+			self.undefine[name] = true
+		else
+			self.variables:set(state, symbol:to_identifier(), VariableMetadata:new(state, symbol, exp))
+		end
 	end,
 	-- define or redefine new overloadable variable in current environment, inheriting existing overload variants from (parent) scopes
 	define_overloadable = function(self, state, symbol, exp)
@@ -132,7 +138,7 @@ local Environment = ast.abstract.Runtime {
 	defined = function(self, state, identifier)
 		if self.variables:has(state, identifier) then
 			return true
-		elseif self.parent then
+		elseif self.parent and not self.undefine[identifier.name] then
 			return self.parent:defined(state, identifier)
 		end
 		return false
@@ -143,9 +149,10 @@ local Environment = ast.abstract.Runtime {
 		local name = symbol.string
 		if self.variables:has(state, symbol:to_identifier()) then
 			return true
-		elseif (self.partial and not self.partial[name])
+		elseif self.parent and not self.undefine[name] then
-			or (self.export ~= symbol.exported) then
+			if (self.partial and not self.partial[name]) or (self.export ~= symbol.exported) then
-			return self.parent:defined_in_current(state, symbol)
+				return self.parent:defined_in_current(state, symbol)
+			end
 		end
 		return false
 	end,
@@ -159,7 +166,7 @@ local Environment = ast.abstract.Runtime {
 		if self:defined(state, identifier) then
 			if self.variables:has(state, identifier) then
 				return self.variables:get(state, identifier)
-			elseif self.parent then
+			elseif self.parent and not self.undefine[identifier.name] then
 				return self.parent:_get_variable(state, identifier)
 			end
 		else

anselme/ast/PartialScope.lua

@@ -1,7 +1,7 @@
 -- create a partial layer to define temporary variables
 
 local ast = require("anselme.ast")
-local Identifier, Quote
+local Identifier, Quote, Nil
 
 local attached_block_identifier, attached_block_symbol
 local unpack = table.unpack or unpack
@@ -11,7 +11,7 @@ PartialScope = ast.abstract.Node {
 	type = "partial scope",
 
 	expression = nil,
-	definitions = nil, -- {[sym]=value,...} where values are already evaluated!
+	definitions = nil, -- {[sym]=value,...}
 	_identifiers = nil, -- {identifier,...} - just a cache so we don't rebuild it on every eval
 
 	init = function(self, expression)
@@ -49,7 +49,7 @@ PartialScope = ast.abstract.Node {
 
 	_eval = function(self, state)
 		state.scope:push_partial(unpack(self._identifiers))
-		for sym, val in pairs(self.definitions) do state.scope:define(sym, val) end
+		for sym, val in pairs(self.definitions) do state.scope:define(sym:eval(state), val:eval(state)) end
 		local exp = self.expression:eval(state)
 		state.scope:pop()
 
@@ -71,14 +71,16 @@ PartialScope = ast.abstract.Node {
 	end,
 	-- class method: return a PartialScope that define the block identifier _ to a Quote of `block`
 	attach_block = function(self, expression, block)
-		local partial = ast.PartialScope:new(expression)
+		local partial = PartialScope:new(expression)
-		partial:define(attached_block_symbol, Quote:new(block))
+		local unpartial = PartialScope:new(block)
+		unpartial:define(attached_block_symbol:with{undefine=true}, Nil:new())
+		partial:define(attached_block_symbol, Quote:new(unpartial))
 		return partial
 	end
 }
 
 package.loaded[...] = PartialScope
-Identifier, Quote = ast.Identifier, ast.Quote
+Identifier, Quote, Nil = ast.Identifier, ast.Quote, ast.Nil
 
 attached_block_identifier = Identifier:new("_")
 attached_block_symbol = attached_block_identifier:to_symbol()

anselme/ast/Symbol.lua

@@ -15,6 +15,7 @@ Symbol = ast.abstract.Node {
 	exported = nil, -- bool
 
 	confined_to_branch = nil, -- bool
+	undefine = nil, -- bool
 
 	init = function(self, str, modifiers)
 		modifiers = modifiers or {}
@@ -24,6 +25,7 @@ Symbol = ast.abstract.Node {
 		self.alias = modifiers.alias
 		self.confined_to_branch = modifiers.confined_to_branch
 		self.exported = modifiers.exported
+		self.undefine = modifiers.undefine
 	end,
 
 	_eval = function(self, state)
@@ -34,7 +36,7 @@ Symbol = ast.abstract.Node {
 
 	with = function(self, modifiers)
 		modifiers = modifiers or {}
-		for _, k in ipairs{"constant", "type_check", "alias", "exported", "confined_to_branch"} do
+		for _, k in ipairs{"constant", "type_check", "alias", "exported", "confined_to_branch", "undefine"} do
 			if modifiers[k] == nil then
 				modifiers[k] = self[k]
 			end

anselme/stdlib/closure.lua

@@ -4,6 +4,8 @@ local assert0 = require("anselme.common").assert0
 
 local calling_environment_manager = require("anselme.state.calling_environment_manager")
 
+local block_identifier = Identifier:new("_")
+
 return {
 	{
 		"defined", "(c::function, s::string)",
@@ -88,21 +90,33 @@ return {
 		end
 	},
 	{
-		"attached block", "(level::number=1)",
+		"attached block", "(level::number=1, keep return=false)",
-		function(state, level)
+		function(state, level, keep_return)
 			-- level 2: env of the function that called the function that called attached block
 			local env = calling_environment_manager:get_level(state, level:to_lua(state)+1)
-			local r = env:get(state, Identifier:new("_"))
+			local r = env:get(state, block_identifier)
-			return Function:with_return_boundary(ParameterTuple:new(), r.expression):eval(state)
+			if keep_return:truthy() then
+				return Function:new(ParameterTuple:new(), r.expression):eval(state)
+			else
+				return Function:with_return_boundary(ParameterTuple:new(), r.expression):eval(state)
+			end
 		end
 	},
 	{
-		"attached block keep return", "(level::number=1)",
+		"attached block", "(level::number=1, keep return=false, default)",
-		function(state, level)
+		function(state, level, keep_return, default)
 			-- level 2: env of the function that called the function that called attached block
 			local env = calling_environment_manager:get_level(state, level:to_lua(state)+1)
-			local r = env:get(state, Identifier:new("_"))
+			if env:defined(state, block_identifier) then
-			return Function:new(ParameterTuple:new(), r.expression):eval(state)
+				local r = env:get(state, block_identifier)
+				if keep_return:truthy() then
+					return Function:new(ParameterTuple:new(), r.expression):eval(state)
+				else
+					return Function:with_return_boundary(ParameterTuple:new(), r.expression):eval(state)
+				end
+			else
+				return default
+			end
 		end
 	},
 }

anselme/stdlib/conditionals.lua

@@ -18,7 +18,7 @@ end
 
 return {
 	{
-		"if", "(condition, expression=attached block keep return!)", function(state, condition, expression)
+		"if", "(condition, expression=attached block(keep return=true))", function(state, condition, expression)
 			ensure_if_variable(state)
 			if condition:truthy() or expression:contains_current_resume_target(state) then
 				set_if_variable(state, true)
@@ -42,7 +42,7 @@ return {
 		end
 	},
 	{
-		"else if", "(condition, expression=attached block keep return!)",
+		"else if", "(condition, expression=attached block(keep return=true))",
 		function(state, condition, expression)
 			ensure_if_variable(state)
 			if (not last_if_success(state) and condition:truthy()) or expression:contains_current_resume_target(state) then
@@ -55,7 +55,7 @@ return {
 		end
 	},
 	{
-		"else", "(expression=attached block keep return!)",
+		"else", "(expression=attached block(keep return=true))",
 		function(state, expression)
 			ensure_if_variable(state)
 			if not last_if_success(state) or expression:contains_current_resume_target(state) then
@@ -67,7 +67,7 @@ return {
 		end
 	},
 	{
-		"while", "(condition, expression=attached block keep return!)",
+		"while", "(condition, expression=attached block(keep return=true))",
 		function(state, condition, expression)
 			ensure_if_variable(state)
 			local cond = condition:call(state, ArgumentTuple:new())

anselme/stdlib/script_script.lua

@@ -8,18 +8,19 @@ return [[
 
 	fn.:check = $(anchor::anchor)
 		fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
-	fn.:checkpoint = $(anchor::anchor)
+	fn.:checkpoint = $(anchor::anchor, on resume=attached block(default=()))
-		fn.current checkpoint = anchor
+		if(on resume)
-		if(resumed from != anchor)
+			fn.current checkpoint = anchor
-			fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
+			if(resumed from == anchor | resuming(4))
-			merge branch!
+				on resume!
-	fn.:checkpoint = $(anchor::anchor, on resume::function)
+			else!
-		fn.current checkpoint = anchor
+				fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
-		if(resumed from == anchor | resuming(2))
+				merge branch!
-			on resume!
 		else!
-			fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
+			fn.current checkpoint = anchor
-			merge branch!
+			if(resumed from != anchor)
+				fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
+				merge branch!
 
 	:f = $
 		if(fn.current checkpoint)

ideas.md

@@ -34,9 +34,8 @@ Standard library.
 * Text manipulation would make sense, but that would require a full UTF-8/Unicode support library like https://github.com/starwing/luautf8.
 * Something to load other files. Maybe not load it by default to let the calling game sandbox Anselme. Probably create an export scope per file to perform some nice module loading.
 * Implement the useful functions from Anselme v1.
-* Checkpoint management.
-* Overloadable :format for custom types.
 * Text manipulation: concatenation, retag/add tags
+* And in general, clean up everything.
 
 ---
 

test/results/checkpoint merging mutable value.ans

@@ -9,8 +9,6 @@
 | {}"1,2,3,4,5: " {}"*[1, 2, 3, 4, 5]" {}"" |
 --- error ---
 cancel merge
-	↳ from test/tests/checkpoint merging mutable value.ans:24:6 in call: error("cancel merge")
-	↳ from ? in block: :l = *[1, 2]…
 --# post run check #--
 --- text ---
 | {}"1,2,3,4: " {}"*[1, 2, 3, 4]" {}"" |

test/results/checkpoint merging variable.ans

@@ -9,8 +9,6 @@
 | {}"4: " {}"4" {}"" |
 --- error ---
 cancel merge
-	↳ from test/tests/checkpoint merging variable.ans:24:6 in call: error("cancel merge")
-	↳ from ? in block: :l = 1…
 --# post run check #--
 --- text ---
 | {}"3: " {}"3" {}"" |

test/results/closure define nested.ans

@@ -3,9 +3,5 @@
 | {}"" {}"42" {}"" |
 --- error ---
 no variable "y" defined in closure
-	↳ from test/tests/closure define nested.ans:12:4 in call: f . "y"
-	↳ from test/tests/closure define nested.ans:12:1 in text interpolation: | {f . "y"} |
-	↳ from test/tests/closure define nested.ans:12:1 in translatable: | {f . "y"} |
-	↳ from ? in block: :f = ($() _)…
 --# saved #--
 {}

test/results/constant variable.ans

@@ -1,7 +1,5 @@
 --# run #--
 --- error ---
 trying to change the value of constant a
-	↳ from test/tests/constant variable.ans:5:3 in assignment: a = 52
-	↳ from ? in block: ::a = 3…
 --# saved #--
 {}

test/results/constrained variable assignement.ans

@@ -5,7 +5,5 @@
 | {}"" {}"type(\"kg\", 12)" {}"" |
 --- error ---
 type check failure for weigh; 32 does not satisfy $(x) type(x) == t
-	↳ from test/tests/constrained variable assignement.ans:9:7 in assignment: weigh = 32
-	↳ from ? in block: :weigh::is("kg") = type(5, "kg")…
 --# saved #--
 {}

test/results/define override function.ans

@@ -1,7 +1,5 @@
 --# run #--
 --- error ---
 a is already defined in the current scope
-	↳ from test/tests/define override function.ans:4:4 in definition: :a = 2
-	↳ from ? in block: :a = ($() _)…
 --# saved #--
 {}

test/results/define override variable.ans

@@ -1,8 +1,5 @@
 --# run #--
 --- error ---
 can't add an overload variant to non-overloadable variable a defined in the same scope
-	↳ from test/tests/define override variable.ans:3:1 in definition: :a = ($() _)
-	↳ from test/tests/define override variable.ans:3:1 in partial scope: :a = ($() _)…
-	↳ from ? in block: :a = 2…
 --# saved #--
 {}

test/results/define override.ans

@@ -1,7 +1,5 @@
 --# run #--
 --- error ---
 a is already defined in the current scope
-	↳ from test/tests/define override.ans:3:4 in definition: :a = 2
-	↳ from ? in block: :a = 5…
 --# saved #--
 {}

test/results/exported variable nested.ans

@@ -6,9 +6,5 @@
 | {}"" {}"42" {}"" |
 --- error ---
 identifier "z" is undefined in branch cf017f8a-7c86-4871-109af-6658231331e6
-	↳ 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 #--
 {}

test/results/function args arity check fail.ans

@@ -1,7 +1,5 @@
 --# run #--
 --- error ---
 can't call function $(a, b) _: expected 2 arguments, received 1
-	↳ from test/tests/function args arity check fail.ans:4:2 in call: f("ok")
-	↳ from ? in block: :f = ($(a, b) _)…
 --# saved #--
 {}

test/results/function conflict.ans

@@ -1,7 +1,5 @@
 --# run #--
 --- error ---
 a function with parameters (a, b) is already defined in the overload
-	↳ from test/tests/function conflict.ans:5:1 in definition: :f = ($(a, b) 0)
-	↳ from ? in block: :f = ($(a, b) 0)…
 --# saved #--
 {}

test/results/function custom type dispatch error.ans

@@ -7,7 +7,5 @@
 can't call overload overload<($(name::($(x) type(x) == t)) _), ($(name::($(x) type(x) == t)) _)>: no function match (type("nope", 5)), possible functions were:
 	• (name::($(x) type(x) == t)): type check failure for parameter name in function (name::($(x) type(x) == t))
 	• (name::($(x) type(x) == t)): type check failure for parameter name in function (name::($(x) type(x) == t))
-	↳ from test/tests/function custom type dispatch error.ans:14:2 in call: a(type(5, "nope"))
-	↳ from ? in block: :french name = "french name"…
 --# saved #--
 {}

test/results/function scope wrong.ans

@@ -1,9 +1,5 @@
 --# run #--
 --- error ---
 identifier "b" is undefined in branch cf017f8a-7c86-4871-109af-6658231331e6
-	↳ from test/tests/function scope wrong.ans:4:7 in identifier: b
-	↳ from test/tests/function scope wrong.ans:4:1 in text interpolation: | a: {b} |
-	↳ from test/tests/function scope wrong.ans:4:1 in translatable: | a: {b} |
-	↳ from ? in block: :a = ($() _)…
 --# saved #--
 {}

test/results/function separate variable from variants.ans

@@ -7,9 +7,5 @@
 	• (c::($(x) <lua function>), s::($(x) <lua function>)) = v: expected 3 arguments, received 2
 	• (c::($(x) <lua function>), s::($(x) <lua function>)) = v: expected 3 arguments, received 2
 	• (c::($(x) <lua function>), s::($(x) <lua function>)): type check failure for parameter c in function (c::($(x) <lua function>), s::($(x) <lua function>))
-	↳ from test/tests/function separate variable from variants.ans:10:4 in call: f . "a"
-	↳ from test/tests/function separate variable from variants.ans:10:1 in text interpolation: | {f . "a"} = 2 |
-	↳ from test/tests/function separate variable from variants.ans:10:1 in translatable: | {f . "a"} = 2 |
-	↳ from ? in block: :f = ($() _)…
 --# saved #--
 {}

test/results/function type dispatch ambigous.ans

@@ -3,7 +3,5 @@
 can't call overload overload<($(a::($(x) <lua function>)) _), ($(x::($(x) <lua function>)) _)>: more than one function match (5), matching functions were at least (specificity 1.3):
 	• (x::($(x) <lua function>))
 	• (a::($(x) <lua function>))
-	↳ from test/tests/function type dispatch ambigous.ans:7:3 in call: fn(5)
-	↳ from ? in block: :fn = ($(x::number) _)…
 --# saved #--
 {}

test/results/list assignement.ans

@@ -11,7 +11,5 @@
 | {}"" {}"*[3, 12, 99]" {}"" |
 --- error ---
 list index out of bounds
-	↳ from test/tests/list assignement.ans:21:6 in call: x(5) = 0
-	↳ from ? in block: :x = *[1, 2]…
 --# saved #--
 {}

test/results/list index.ans

@@ -9,9 +9,5 @@
 | {}"" {}"3" {}" == " {}"3" {}"" |
 --- error ---
 tuple index out of bounds
-	↳ from test/tests/list index.ans:11:4 in call: x(-4)
-	↳ from test/tests/list index.ans:11:1 in text interpolation: | {x(-4)} |
-	↳ from test/tests/list index.ans:11:1 in translatable: | {x(-4)} |
-	↳ from ? in block: :x = [1, 2, 3]…
 --# saved #--
 {}

test/results/merge nested mutable error bis.ans

@@ -1,23 +1,6 @@
 --# run #--
 --- error ---
-abort
+abort
-	↳ from test/tests/merge nested mutable error bis.ans:14:7 in call: error("abort")
-	↳ from test/tests/merge nested mutable error bis.ans:3:1 in block: insert(a, b)…
-	↳ from test/tests/merge nested mutable error bis.ans:3:18 in call: _
-	↳ from test/tests/merge nested mutable error bis.ans:3:17 in return boundary: _
-	↳ from script.ans:29:6 in call: fn!
-	↳ from script.ans:27:3 in block: resumed from = ()…
-	↳ from script.ans:27:7 in call: else!
-	↳ from script.ans:27:3 in partial scope: else!…
-	↳ from script.ans:23:2 in block: if(fn . "current checkpoint")…
-	↳ from script.ans:23:9 in call: _
-	↳ from script.ans:23:7 in return boundary: _
-	↳ from script.ans:37:9 in call: value(s)!
-	↳ from script.ans:36:1 in block: value(s)!
-	↳ from script.ans:36:20 in call: _
-	↳ from script.ans:36:1 in return boundary: _
-	↳ from test/tests/merge nested mutable error bis.ans:19:2 in call: f!
-	↳ from ? in block: :a = *[1]…
 --# post run check #--
 --- text ---
 | {}"[1,[2,3]]: " {}"*[1, *[2, 3]]" {}"" |

test/results/merge nested mutable error.ans

@@ -1,23 +1,6 @@
 --# run #--
 --- error ---
-abort
+abort
-	↳ from test/tests/merge nested mutable error.ans:14:7 in call: error("abort")
-	↳ from test/tests/merge nested mutable error.ans:3:1 in block: insert(a, b)…
-	↳ from test/tests/merge nested mutable error.ans:3:18 in call: _
-	↳ from test/tests/merge nested mutable error.ans:3:17 in return boundary: _
-	↳ from script.ans:29:6 in call: fn!
-	↳ from script.ans:27:3 in block: resumed from = ()…
-	↳ from script.ans:27:7 in call: else!
-	↳ from script.ans:27:3 in partial scope: else!…
-	↳ from script.ans:23:2 in block: if(fn . "current checkpoint")…
-	↳ from script.ans:23:9 in call: _
-	↳ from script.ans:23:7 in return boundary: _
-	↳ from script.ans:37:9 in call: value(s)!
-	↳ from script.ans:36:1 in block: value(s)!
-	↳ from script.ans:36:20 in call: _
-	↳ from script.ans:36:1 in return boundary: _
-	↳ from test/tests/merge nested mutable error.ans:19:2 in call: f!
-	↳ from ? in block: :a = *[1]…
 --# post run check #--
 --- text ---
 | {}"[1,[2,3]]: " {}"*[1, *[2, 3]]" {}"" |

test/results/scope checkpoint mutable bis error.ans

@@ -14,20 +14,7 @@
 --- text ---
 | {}"CHECK 2" |
 --- error ---
-t
+t
-	↳ from test/tests/scope checkpoint mutable bis error.ans:32:7 in call: error("t")
-	↳ from test/tests/scope checkpoint mutable bis error.ans:7:1 in block: insert(t, len(l) + 1)…
-	↳ from test/tests/scope checkpoint mutable bis error.ans:7:8 in call: _
-	↳ from test/tests/scope checkpoint mutable bis error.ans:7:1 in return boundary: _
-	↳ from test/tests/scope checkpoint mutable bis error.ans:19:4 in call: f(t)
-	↳ from test/tests/scope checkpoint mutable bis error.ans:15:2 in block: | REC |…
-	↳ from test/tests/scope checkpoint mutable bis error.ans:15:4 in call: if(n < 1)
-	↳ from test/tests/scope checkpoint mutable bis error.ans:15:2 in partial scope: if(n < 1)…
-	↳ from test/tests/scope checkpoint mutable bis error.ans:7:1 in block: insert(t, len(l) + 1)…
-	↳ from test/tests/scope checkpoint mutable bis error.ans:7:8 in call: _
-	↳ from test/tests/scope checkpoint mutable bis error.ans:7:1 in return boundary: _
-	↳ from test/tests/scope checkpoint mutable bis error.ans:41:2 in call: f(l)
-	↳ from ? in block: :x = *[99]…
 --# post run check #--
 --- text ---
 | {}"AFTER ERROR" |

test/results/scope checkpoint mutable error.ans

@@ -10,20 +10,7 @@
 --- text ---
 | {}"CHECK" |
 --- error ---
-t
+t
-	↳ from test/tests/scope checkpoint mutable error.ans:23:7 in call: error("t")
-	↳ from test/tests/scope checkpoint mutable error.ans:5:1 in block: insert(t, len(l) + 1)…
-	↳ from test/tests/scope checkpoint mutable error.ans:5:8 in call: _
-	↳ from test/tests/scope checkpoint mutable error.ans:5:1 in return boundary: _
-	↳ from test/tests/scope checkpoint mutable error.ans:17:4 in call: f(t)
-	↳ from test/tests/scope checkpoint mutable error.ans:13:2 in block: | REC |…
-	↳ from test/tests/scope checkpoint mutable error.ans:13:4 in call: if(n < 1)
-	↳ from test/tests/scope checkpoint mutable error.ans:13:2 in partial scope: if(n < 1)…
-	↳ from test/tests/scope checkpoint mutable error.ans:5:1 in block: insert(t, len(l) + 1)…
-	↳ from test/tests/scope checkpoint mutable error.ans:5:8 in call: _
-	↳ from test/tests/scope checkpoint mutable error.ans:5:1 in return boundary: _
-	↳ from test/tests/scope checkpoint mutable error.ans:32:2 in call: f(l)
-	↳ from ? in block: :l = *[1]…
 --# post run check #--
 --- text ---
 | {}"AFTER ERROR" |

test/results/scope checkpoint mutable ter error.ans

@@ -14,20 +14,7 @@
 --- text ---
 | {}"CHECK 2" |
 --- error ---
-t
+t
-	↳ from test/tests/scope checkpoint mutable ter error.ans:34:7 in call: error("t")
-	↳ from test/tests/scope checkpoint mutable ter error.ans:7:1 in block: insert(t, len(l) + 1)…
-	↳ from test/tests/scope checkpoint mutable ter error.ans:7:8 in call: _
-	↳ from test/tests/scope checkpoint mutable ter error.ans:7:1 in return boundary: _
-	↳ from test/tests/scope checkpoint mutable ter error.ans:19:4 in call: f(t)
-	↳ from test/tests/scope checkpoint mutable ter error.ans:15:2 in block: | REC |…
-	↳ from test/tests/scope checkpoint mutable ter error.ans:15:4 in call: if(n < 1)
-	↳ from test/tests/scope checkpoint mutable ter error.ans:15:2 in partial scope: if(n < 1)…
-	↳ from test/tests/scope checkpoint mutable ter error.ans:7:1 in block: insert(t, len(l) + 1)…
-	↳ from test/tests/scope checkpoint mutable ter error.ans:7:8 in call: _
-	↳ from test/tests/scope checkpoint mutable ter error.ans:7:1 in return boundary: _
-	↳ from test/tests/scope checkpoint mutable ter error.ans:43:2 in call: f(l)
-	↳ from ? in block: :x = *[99]…
 --# post run check #--
 --- text ---
 | {}"AFTER ERROR" |

test/results/symbol alias constant.ans

@@ -6,7 +6,5 @@
 | {}"d=" {}"2" {}" (2)" |
 --- error ---
 trying to change the value of constant d
-	↳ from test/tests/symbol alias constant.ans:12:3 in assignment: d = 5
-	↳ from ? in block: :l = *[1, 2, 3]…
 --# saved #--
 {}

test/run.lua

@@ -47,6 +47,8 @@ local function run_loop(run_state, out)
 		elseif e == "return" then
 			table.insert(out, data:format(run_state))
 			run_state:merge()
+		elseif e == "error" then
+			table.insert(out, (tostring(data):gsub("\n%s*↳[^\n]*", ""))) -- traceback change every day and a half due to AST changes. TODO: only keep ast layers relevant for the user
 		else
 			table.insert(out, tostring(data))
 		end