Add variable reference and use them in alias(ref, id)

REFERENCE.md

@@ -534,6 +534,8 @@ Default types are:
 
 * `function reference`: reference to one or more function(s) with a given name. Can be defined using `&function name`, which will create a reference to every function with this name accessible from the current namespace. Can be called as if it was the original function using `func ref!` and `func ref(args)`.
 
+* `variable reference`: reference to a single variable with a given name. Can be defined using `&variable name`, which will create a reference to the closest variable with this name accessible from the current namespace. Can get the referenced variable value using `var ref!`.
+
 * `list`: a list of values. Mutable. Types can be mixed. Can be defined between square brackets and use comma as a separator '[1,2,3,4]'.
 
 Every type is immutable, except `list`.
@@ -835,7 +837,7 @@ This only works on strings:
 
 `a | b`: or operator, lazy
 
-##### Functions
+##### Functions and function references
 
 `fn(args)`: call the function, checkpoint or function reference with the given arguments.
 
@@ -845,6 +847,12 @@ This only works on strings:
 
 `a!fn(args)`: call the function or function reference with the variable as first argument. Parantheses are optional.
 
+##### Variable references
+
+`&var`: returns a variable reference to the given variable.
+
+`a!`: returns the value associated with the reference variable.
+
 ##### Various
 
 `a ; b`: evaluate a, discard its result, then evaluate b. Returns the result of b.
@@ -891,7 +899,7 @@ This only works on strings:
 
 ##### Various
 
-`alias(identifier::string, alias::string)`: define an alias `alias` for variable `identifier`. Expect fully qualified names.
+`alias(ref::reference, alias::string)`: define an alias `alias` for the variable or function referenced by `ref`. Expect fully qualified names for the alias.
 
 `rand([m[, n]])`: when called whitout arguments, returns a random float in [0,1). Otherwise, returns a random number in [m,n]; m=1 if not given.
 
@@ -903,7 +911,7 @@ This only works on strings:
 
 #### Built-in variables
 
-Variables for default types (each is associated to a string of the internal variable type name): `nil`, `number`, `string`, `list`, `pair`, `function reference`.
+Variables for default types (each is associated to a string of the internal variable type name): `nil`, `number`, `string`, `list`, `pair`, `function reference`, `variable reference`.
 
 #### Built-in languages
 

anselme.lua

@@ -197,6 +197,8 @@ local interpreter_methods = {
 		anselme.running = previous
 		if not success then
 			return nil, event
+		elseif event == "error" then
+			return nil, data
 		elseif event ~= "return" then
 			return nil, ("evaluated expression generated an %q event; at %s"):format(event, self.state.interpreter.running_line.source)
 		else

interpreter/expression.lua

@@ -148,12 +148,18 @@ local function eval(state, exp)
 	-- variable
 	elseif exp.type == "variable" then
 		return get_variable(state, exp.name)
-	-- function
+	-- references
 	elseif exp.type == "function reference" then
 		return {
 			type = "function reference",
 			value = exp.names
 		}
+	elseif exp.type == "variable reference" then
+		return {
+			type = "variable reference",
+			value = exp.name
+		}
+	-- function
 	elseif exp.type == "function call" then
 		-- eval args: list_brackets
 		local args = {}
@@ -372,7 +378,7 @@ local function eval(state, exp)
 						if r then
 							ret = r
 						else
-							return nil, ("%s; in Lua function %q"):format(e, exp.called_name)
+							return nil, ("%s; in Lua function %q"):format(e or "raw function returned nil and no error message", exp.called_name)
 						end
 					-- untyped raw mode: same as raw, but strips custom types from the arguments
 					elseif lua_fn.mode == "untyped raw" then
@@ -386,7 +392,7 @@ local function eval(state, exp)
 						if r then
 							ret = r
 						else
-							return nil, ("%s; in Lua function %q"):format(e, exp.called_name)
+							return nil, ("%s; in Lua function %q"):format(e or "untyped raw function returned nil and no error message", exp.called_name)
 						end
 					-- normal mode: convert args to Lua and convert back Lua value to Anselme
 					elseif lua_fn.mode == nil then

parser/common.lua

@@ -6,16 +6,19 @@ local common
 
 --- rewrite name to use defined aliases (under namespace only)
 -- namespace should not contain aliases
+-- returns the final fqm
 local replace_aliases = function(aliases, namespace, name)
-	namespace = namespace == "" and "" or namespace.."."
 	local name_list = common.split(name)
-	for i=1, #name_list, 1 do
-		local n = ("%s%s"):format(namespace, table.concat(name_list, ".", 1, i))
+	local prefix = namespace
+	for i=1, #name_list, 1 do -- search alias for each part of the fqm
+		local n = ("%s%s%s"):format(prefix, prefix == "" and "" or ".", name_list[i])
 		if aliases[n] then
-			name_list[i] = aliases[n]:match("[^%.]+$")
+			prefix = aliases[n]
+		else
+			prefix = n
 		end
 	end
-	return table.concat(name_list, ".")
+	return prefix
 end
 
 local disallowed_set = ("~`^+-=<>/[]*{}|\\_!?,;:()\"@&$#%"):gsub("[^%w]", "%%%1")
@@ -93,7 +96,7 @@ common = {
 		local ns = common.split(namespace)
 		for i=#ns, 1, -1 do
 			local current_namespace = table.concat(ns, ".", 1, i)
-			local fqm = ("%s.%s"):format(current_namespace, replace_aliases(aliases, current_namespace, name))
+			local fqm = replace_aliases(aliases, current_namespace, name)
 			if list[fqm] then
 				return list[fqm], fqm
 			end
@@ -112,7 +115,7 @@ common = {
 		local ns = common.split(namespace)
 		for i=#ns, 1, -1 do
 			local current_namespace = table.concat(ns, ".", 1, i)
-			local fqm = ("%s.%s"):format(current_namespace, replace_aliases(aliases, current_namespace, name))
+			local fqm = replace_aliases(aliases, current_namespace, name)
 			if list[fqm] then
 				table.insert(l, fqm)
 			end

parser/expression.lua

@@ -190,15 +190,27 @@ local function expression(s, state, namespace, current_priority, operating_on)
 				local escaped = escape(op)
 				if s:match("^"..escaped) then
 					local sright = s:match("^"..escaped.."(.*)$")
-					-- function reference
+					-- function and variable reference
 					if op == "&" and sright:match("^"..identifier_pattern) then
 						local name, r = sright:match("^("..identifier_pattern..")(.-)$")
 						name = format_identifier(name)
 						-- get all functions this name can reference
-						-- try prefixes until we find a valid function name
+						-- try prefixes until we find a valid function or variable name
 						local nl = split(name)
 						for i=#nl, 1, -1 do
 							local name_prefix = table.concat(nl, ".", 1, i)
+							-- variable ref
+							local var, vfqm = find(state.aliases, state.variables, namespace, name_prefix)
+							if var then
+								if i < #nl then
+									r = "."..table.concat(nl, ".", i+1, #nl)..r
+								end
+								return expression(r, state, namespace, current_priority, {
+									type = "variable reference",
+									name = vfqm
+								})
+							end
+							-- function ref
 							local lfnqm = find_all(state.aliases, state.functions, namespace, name_prefix)
 							if #lfnqm > 0 then
 								if i < #nl then

stdlib/bootscript.lua

@@ -7,4 +7,5 @@ return [[
 :list="list"
 :pair="pair"
 :function reference="function reference"
+:variable reference="variable reference"
 ]]

stdlib/functions.lua

@@ -145,9 +145,15 @@ functions = {
 	["()(fn::function reference, l...)"] = {
 		-- bypassed, this case is manually handled in the expression interpreter
 	},
-	["_!(fn::function reference, l...)"] = {
+	["_!(fn::function reference)"] = {
 		-- bypassed, this case is manually handled in the expression interpreter
 	},
+	["_!(fn::variable reference)"] = {
+		mode = "untyped raw",
+		value = function(v)
+			return anselme.running.state.variables[v.value]
+		end
+	},
 	-- format
 	["{}(v)"] = {
 		mode = "raw",
@@ -156,21 +162,40 @@ functions = {
 		end
 	},
 	-- alias
-	["alias(identifier::string, alias::string)"] = {
-		value = function(identifier, alias)
+	["alias(ref::function reference, alias::string)"] = {
+		mode = "untyped raw",
+		value = function(ref, alias)
 			-- check identifiers
-			local fqm = identifier:match("^"..identifier_pattern.."$")
-			if not fqm then error(("%q is not a valid identifier"):format(identifier)) end
-			fqm = format_identifier(fqm)
+			alias = alias.value
+			local aliasfqm = alias:match("^"..identifier_pattern.."$")
+			if not aliasfqm then error(("%q is not a valid identifier for an alias"):format(alias)) end
+			aliasfqm = format_identifier(aliasfqm)
+			-- define alias
+			for _, fnfqm in ipairs(ref.value) do
+				local aliases = anselme.running.state.aliases
+				if aliases[aliasfqm] ~= nil and aliases[aliasfqm] ~= fnfqm then
+					error(("trying to define alias %q for %q, but already exist and refer to %q"):format(aliasfqm, fnfqm, aliases[alias]))
+				end
+				aliases[aliasfqm] = fnfqm
+			end
+			return { type = "nil" }
+		end
+	},
+	["alias(ref::variable reference, alias::string)"] = {
+		mode = "untyped raw",
+		value = function(ref, alias)
+			-- check identifiers
+			alias = alias.value
 			local aliasfqm = alias:match("^"..identifier_pattern.."$")
 			if not aliasfqm then error(("%q is not a valid identifier for an alias"):format(alias)) end
 			aliasfqm = format_identifier(aliasfqm)
 			-- define alias
 			local aliases = anselme.running.state.aliases
-			if aliases[aliasfqm] ~= nil and aliases[aliasfqm] ~= fqm then
-				error(("trying to define alias %q for %q, but already exist and refer to %q"):format(aliasfqm, fqm, aliases[alias]))
+			if aliases[aliasfqm] ~= nil and aliases[aliasfqm] ~= ref.value then
+				error(("trying to define alias %q for %q, but already exist and refer to %q"):format(aliasfqm, ref.value, aliases[alias]))
 			end
-			aliases[aliasfqm] = fqm
+			aliases[aliasfqm] = ref.value
+			return { type = "nil" }
 		end
 	},
 	-- pair methods

stdlib/languages/frFR.lua

@@ -1,27 +1,29 @@
 return [[
 (Types)
-~ "nil"!alias("nul")
-~ "number"!alias("nombre")
-~ "string"!alias("texte")
-~ "list"!alias("liste")
-~ "pair"!alias("paire")
+~ &nil!alias("nul")
+~ &number!alias("nombre")
+~ &string!alias("texte")
+~ &list!alias("liste")
+~ &pair!alias("paire")
+~ &function reference!alias("réference de fonction")
+~ &variable reference!alias("réference de variable")
 
 (Built-in functions)
-(~ "alias"!alias("alias")
-~ "name"!alias("nom")
-~ "value"!alias("valeur")
-~ "len"!alias("longueur")
-~ "insert"!alias("ajouter")
-~ "remove"!alias("retirer")
-~ "find"!alias("trouver")
-~ "error"!alias("erreur")
-~ "rand"!alias("aléa")
-~ "raw"!alias("brut")
-(~ "type"!alias("type")
-~ "is of type"!alias("est de type")
-~ "cycle"!alias("cycler")
-~ "random"!alias("aléatoire")
-~ "next"!alias("séquence")
+(~ &alias!alias("alias")
+~ &name!alias("nom")
+~ &value!alias("valeur")
+~ &len!alias("longueur")
+~ &insert!alias("ajouter")
+~ &remove!alias("retirer")
+~ &find!alias("trouver")
+~ &error!alias("erreur")
+~ &rand!alias("aléa")
+~ &raw!alias("brut")
+(~ &type!alias("type")
+~ &is of type!alias("est de type")
+~ &cycle!alias("cycler")
+~ &random!alias("aléatoire")
+~ &next!alias("séquence")
 
 (Built-in variables)
 :alias 👁️ = "vu"

stdlib/types.lua

@@ -145,7 +145,22 @@ types.anselme = {
 			return k
 		end
 	},
-	["function reference"] = nil,
+	["function reference"] = {
+		format = function(val)
+			if #val > 1 then
+				return ("&(%s)"):format(table.concat(val, ", "))
+			else
+				return ("&%s"):format(table.concat(val, ", "))
+			end
+		end,
+		to_lua = nil
+	},
+	["variable reference"] = {
+		format = function(val)
+			return ("&%s"):format(val)
+		end,
+		to_lua = nil
+	},
 	-- internal types
 	["event buffer"] = {
 		format = function(val) -- triggered from subtexts

test/tests/variable reference get value.ans

@@ -0,0 +1,5 @@
+:x = 52
+
+:y = &x
+
+{y!}

test/tests/variable reference get value.lua

@@ -0,0 +1,14 @@
+local _={}
+_[5]={}
+_[4]={tags=_[5],text="52"}
+_[3]={_[4]}
+_[2]={"return"}
+_[1]={"text",_[3]}
+return {_[1],_[2]}
+--[[
+{ "text", { {
+      tags = {},
+      text = "52"
+    } } }
+{ "return" }
+]]--