improved line break heuristics

Closes #740.

spec/code_gen/linebreak_spec.lua

@@ -0,0 +1,31 @@
+local util = require("spec.util")
+
+describe("improved line break heuristics", function()
+   it("a line starting with ( is not a function call for the previous line", util.gen([[
+      local record Obj
+      end
+
+      function Obj:meth1()
+         print("hehe")
+      end
+
+      local t = setmetatable({}, { __index = Obj })
+      do
+         (t as Obj):meth1()
+         (t as Obj):meth1()
+      end
+   ]], [[
+      local Obj = {}
+
+
+      function Obj:meth1()
+         print("hehe")
+      end
+
+      local t = setmetatable({}, { __index = Obj })
+      do
+         (t):meth1();
+         (t):meth1()
+      end
+   ]]))
+end)

tl.lua

@@ -2973,6 +2973,12 @@ do
 
                e1 = { f = ps.filename, y = tkop.y, x = tkop.x, kind = "op", op = op, e1 = e1, e2 = key }
             elseif tkop.tk == "(" then
+               local prev_tk = ps.tokens[i - 1]
+               if tkop.y > prev_tk.y then
+                  table.insert(ps.tokens, i, { y = prev_tk.y, x = prev_tk.x + #prev_tk.tk, tk = ";", kind = ";" })
+                  break
+               end
+
                local op = new_operator(tkop, 2, "@funcall")
 
                local prev_i = i

tl.tl

@@ -2973,6 +2973,12 @@ do
 
             e1 = { f = ps.filename, y = tkop.y, x = tkop.x, kind = "op", op = op, e1 = e1, e2 = key }
          elseif tkop.tk == "(" then
+            local prev_tk = ps.tokens[i - 1]
+            if tkop.y > prev_tk.y then
+               table.insert(ps.tokens, i, { y = prev_tk.y, x = prev_tk.x + #prev_tk.tk, tk = ";", kind = ";" })
+               break
+            end
+
             local op: Operator = new_operator(tkop, 2, "@funcall")
 
             local prev_i = i