feat: implement global keyword in lua55 writer

candran/can-parser/parser.lua

@@ -1,5 +1,5 @@
 --[[
-This module implements a parser for Lua 5.3 with LPeg,
+This module implements a parser for Lua 5.5 with LPeg,
 and generates an Abstract Syntax Tree that is similar to the one generated by Metalua.
 For more information about Metalua, please, visit:
 https://github.com/fab13n/metalua-parser
@@ -15,8 +15,11 @@ stat:
   | `Fornum{ ident expr expr expr? block }    -- for ident = e, e[, e] do b end
   | `Forin{ {ident+} {expr+} block }          -- for i1, i2... in e1, e2... do b end
   | `Local{ {attributeident+} {expr+}? }      -- local i1, i2... = e1, e2...
+  | `Global{ {attributeident+} {expr+}? }     -- global i1, i2... = e1, e2...
   | `Let{ {ident+} {expr+}? }                 -- let i1, i2... = e1, e2...
   | `Localrec{ {ident} {expr} }               -- only used for 'local function'
+  | `Globalrec{ {ident} {expr} }              -- only used for 'global function'
+  | `GlobalAll{ attribute? }                  -- only used for 'global *'
   | `Goto{ <string> }                         -- goto str
   | `Label{ <string> }                        -- ::str::
   | `Return{ <expr*> }                        -- return e1, e2...
@@ -112,6 +115,7 @@ local labels = {
   { "ErrEListFor", "expected one or more expressions after 'in'" },
   { "ErrDoFor", "expected 'do' after the range of the for loop" },
 
+  { "ErrDefGlobal", "expected a function definition or assignment after global" },
   { "ErrDefLocal", "expected a function definition or assignment after local" },
   { "ErrDefLet", "expected an assignment after let" },
   { "ErrDefClose", "expected an assignment after close" },
@@ -340,10 +344,10 @@ end
 local function searchEndRec (block, isRecCall) -- recursively search potential "end" keyword wrongly consumed by a short anonymous function on stat end (yeah, too late to change the syntax to something easier to parse)
     for i, stat in ipairs(block) do
         -- Non recursive statements
-        if stat.tag == "Set" or stat.tag == "Push" or stat.tag == "Return" or stat.tag == "Local" or stat.tag == "Let" or stat.tag == "Localrec" then
+        if stat.tag == "Set" or stat.tag == "Push" or stat.tag == "Return" or stat.tag == "Local" or stat.tag == "Let" or stat.tag == "Localrec" or stat.tag == "Global" or stat.tag == "Globalrec" then
             local exprlist
 
-            if stat.tag == "Set" or stat.tag == "Local" or stat.tag == "Let" or stat.tag == "Localrec" then
+            if stat.tag == "Set" or stat.tag == "Local" or stat.tag == "Let" or stat.tag == "Localrec" or stat.tag == "Global" or stat.tag == "Globalrec" then
                 exprlist = stat[#stat]
             elseif stat.tag == "Push" or stat.tag == "Return" then
                 exprlist = stat
@@ -515,7 +519,7 @@ local G = { V"Lua",
 
   Block       = tagC("Block", (V"Stat" + -V"BlockEnd" * throw("InvalidStat"))^0 * ((V"RetStat" + V"ImplicitPushStat") * sym(";")^-1)^-1);
   Stat        = V"IfStat" + V"DoStat" + V"WhileStat" + V"RepeatStat" + V"ForStat"
-              + V"LocalStat" + V"FuncStat" + V"BreakStat" + V"LabelStat" + V"GoToStat"
+              + V"LocalStat" + V"GlobalStat" + V"FuncStat" + V"BreakStat" + V"LabelStat" + V"GoToStat"
               + V"LetStat" + V"ConstStat" + V"CloseStat"
               + V"FuncCall" + V"Assignment"
               + V"ContinueStat" + V"PushStat"
@@ -542,6 +546,12 @@ local G = { V"Lua",
   ForIn     = tagC("Forin", V"DestructuringNameList" * expect(kw("in"), "InFor") * expect(V"ExprList", "EListFor") * V"ForBody");
   ForBody   = expectBlockOrSingleStatWithStartEnd(kw("do"), "DoFor", "EndFor");
 
+  GlobalStat    = kw("global") * expect(V"GlobalFunc" + V"GlobalAssign", "DefGlobal");
+  GlobalFunc    = tagC("Globalrec", kw("function") * expect(V"Id", "NameLFunc") * V"FuncBody") / fixFuncStat;
+  GlobalAssign  = tagC("Global", V"AttributeNameList" * (sym("=") * expect(V"ExprList", "EListLAssign") + Ct(Cc())))
+               + tagC("Global", V"DestructuringNameList" * sym("=") * expect(V"ExprList", "EListLAssign"))
+               + tagC("GlobalAll", V "Attribute"^-1 * sym("*")),
+
   LocalStat    = kw("local") * expect(V"LocalFunc" + V"LocalAssign", "DefLocal");
   LocalFunc    = tagC("Localrec", kw("function") * expect(V"Id", "NameLFunc") * V"FuncBody") / fixFuncStat;
   LocalAssign  = tagC("Local", V"AttributeNameList" * (sym("=") * expect(V"ExprList", "EListLAssign") + Ct(Cc())))
@@ -551,9 +561,9 @@ local G = { V"Lua",
   LetAssign    = tagC("Let", V"NameList" * (sym("=") * expect(V"ExprList", "EListLAssign") + Ct(Cc())))
                + tagC("Let", V"DestructuringNameList" * sym("=") * expect(V"ExprList", "EListLAssign"));
 
-  ConstStat       = kw("const") * expect(V"AttributeAssign" / setAttribute("const"), "DefConst");
+  ConstStat                = kw("const") * expect(V "LocalAssignNoAttribute" / setAttribute("const"), "DefConst"),
-  CloseStat       = kw("close") * expect(V"AttributeAssign" / setAttribute("close"), "DefClose");
+  CloseStat                = kw("close") * expect(V "LocalAssignNoAttribute" / setAttribute("close"), "DefClose"),
-  AttributeAssign = tagC("Local", V"NameList" * (sym("=") * expect(V"ExprList", "EListLAssign") + Ct(Cc())))
+  LocalAssignNoAttribute = tagC("Local", V"NameList" * (sym("=") * expect(V"ExprList", "EListLAssign") + Ct(Cc())))
                   + tagC("Local", V"DestructuringNameList" * sym("=") * expect(V"ExprList", "EListLAssign"));
 
   Assignment   = tagC("Set", (V"VarList" + V"DestructuringNameList") * V"BinOp"^-1 * (P"=" / "=") * ((V"BinOp" - P"-") + #(P"-" * V"Space") * V"BinOp")^-1 * V"Skip" * expect(V"ExprList", "EListAssign"));
@@ -677,7 +687,7 @@ local G = { V"Lua",
   Reserved  = V"Keywords" * -V"IdRest";
   Keywords  = P"and" + "break" + "do" + "elseif" + "else" + "end"
             + "false" + "for" + "function" + "goto" + "if" + "in"
-            + "local" + "nil" + "not" + "or" + "repeat" + "return"
+            + "local" + "global" + "nil" + "not" + "or" + "repeat" + "return"
             + "then" + "true" + "until" + "while";
   Ident     = V"IdStart" * V"IdRest"^0;
   IdStart   = alpha + P"_";

candran/can-parser/pp.lua

@@ -245,7 +245,7 @@ function stm2str (stm)
     str = str .. explist2str(stm[2]) .. ", "
     str = str .. block2str(stm[3])
     str = str .. " }"
-  elseif tag == "Local" then -- `Local{ {ident+} {expr+}? }
+  elseif tag == "Local" or tag == "Global" then -- `Local|Global{ {ident+} {expr+}? }
     str = str .. "{ "
     str = str .. varlist2str(stm[1])
     if #stm[2] > 0 then
@@ -254,7 +254,7 @@ function stm2str (stm)
       str = str .. ", " .. "{  }"
     end
     str = str .. " }"
-  elseif tag == "Localrec" then -- `Localrec{ ident expr }
+  elseif tag == "Localrec" or tag == "Globalrec" then -- `Localrec|Globalrec{ ident expr }
     str = str .. "{ "
     str = str .. "{ " .. var2str(stm[1][1]) .. " }, "
     str = str .. "{ " .. exp2str(stm[2][1]) .. " }"

candran/can-parser/validator.lua

@@ -1,5 +1,9 @@
 --[[
-This module impements a validator for the AST
+This module impements a validator for the AST.
+
+TODO/Checks that could be added in the future:
+- Check if attributes are valid in declarations: in AttributeNameList, PrefixedAttributeNameList, and GlobalAll
+- Check global variable declarations
 ]]
 local scope = require "candran.can-parser.scope"
 
@@ -395,10 +399,14 @@ function traverse_stm (env, stm)
   elseif tag == "Forin" then -- `Forin{ {ident+} {expr+} block }
     return traverse_forin(env, stm)
   elseif tag == "Local" or -- `Local{ {ident+} {expr+}? }
-         tag == "Let" then -- `Let{ {ident+} {expr+}? }
+         tag == "Let" or -- `Let{ {ident+} {expr+}? }
+         tag == "Global" then -- `Global{ {ident+} {expr+}? }
     return traverse_let(env, stm)
-  elseif tag == "Localrec" then -- `Localrec{ ident expr }
+  elseif tag == "Localrec" or -- `Localrec{ ident expr }
+          tag == "Globalrec" then -- `Globalrec{ ident expr }
     return traverse_letrec(env, stm)
+  elseif tag == "GlobalAll" then  -- GlobalAll{ attribute? }
+    return true
   elseif tag == "Goto" then -- `Goto{ <string> }
     return traverse_goto(env, stm)
   elseif tag == "Label" then -- `Label{ <string> }

compiler/lua54.can

@@ -1,5 +1,15 @@
 targetName = "Lua 5.4"
 
+tags.Global = (t)
+	error("NYI")
+end
+tags.Globalrec = (t)
+	error("NYI")
+end
+tags.GlobalAll = (t)
+	error("NYI")
+end
+
 #placeholder("patch")
 
 #local patch = output

compiler/lua55.can

@@ -471,6 +471,15 @@ return function(code, ast, options, macros={functions={}, variables={}})
 			end
 			return r..DESTRUCTURING_ASSIGN(destructured)
 		end,
+		-- Global{ {attributeident+} {expr+}? }
+		Global = (t)
+			local destructured = {}
+			local r = "global "..push("destructuring", destructured)..lua(t[1])..pop("destructuring")
+			if t[2][1] then
+				r ..= " = "..lua(t[2], "_lhs")
+			end
+			return r..DESTRUCTURING_ASSIGN(destructured)
+		end,
 		-- Let{ {ident+} {expr+}? }
 		Let = (t)
 			local destructured = {}
@@ -489,6 +498,18 @@ return function(code, ast, options, macros={functions={}, variables={}})
 		Localrec = (t)
 			return "local function "..lua(t[1][1])..lua(t[2][1], "_functionWithoutKeyword")
 		end,
+		-- Globalrec{ {ident} {expr} }
+		Globalrec = (t)
+			return "global function "..lua(t[1][1])..lua(t[2][1], "_functionWithoutKeyword")
+		end,
+		-- GlobalAll{ attribute? }
+		GlobalAll = (t)
+			if #t == 1 then
+				return "global <" .. t[1] .. "> *"
+			else
+				return "global *"
+			end
+		end,
 		-- Goto{ <string> }
 		Goto = (t)
 			return "goto "..lua(t, "Id")