Added check for circular imports.

2 files changed, 31 insertions, 6 deletions

diff --git a/nomsu.lua b/nomsu.lua
index 94eec80..60f74ea 100644
--- a/nomsu.lua
+++ b/nomsu.lua
@@ -416,9 +416,26 @@ do
         return error("Invalid filetype for " .. tostring(filename), 0)
       end
     end,
-    require_file = function(self, filename)
+    use_file = function(self, filename)
       local loaded = self.environment.LOADED
       if not loaded[filename] then
+        for i, f in ipairs(self.use_stack) do
+          if f == filename then
+            local loop
+            do
+              local _accum_0 = { }
+              local _len_0 = 1
+              for j = i, #self.use_stack do
+                _accum_0[_len_0] = self.use_stack[j]
+                _len_0 = _len_0 + 1
+              end
+              loop = _accum_0
+            end
+            insert(loop, filename)
+            error("Circular import, this loops forever: " .. tostring(concat(loop, " -> ")))
+          end
+        end
+        insert(self.use_stack, filename)
         loaded[filename] = self:run_file(filename) or true
       end
       return loaded[filename]
@@ -1358,9 +1375,9 @@ do
       end)
       return self:define_compile_action("use %filename", get_line_no(), function(_filename)
         local filename = nomsu:tree_to_value(_filename)
-        nomsu:require_file(filename)
+        nomsu:use_file(filename)
         return {
-          expr = "nomsu:require_file(" .. tostring(repr(filename)) .. ");"
+          expr = "nomsu:use_file(" .. tostring(repr(filename)) .. ");"
         }
       end)
     end
@@ -1383,6 +1400,7 @@ do
           return id
         end
       })
+      self.use_stack = { }
       self.compilestack = { }
       self.debug = false
       self.environment = {
diff --git a/nomsu.moon b/nomsu.moon
index cb2efdd..0c58a2d 100755
--- a/nomsu.moon
+++ b/nomsu.moon
@@ -155,6 +155,7 @@ class NomsuCompiler
                 @[key] = id
                 return id
         })
+        @use_stack = {}
         @compilestack = {}
         @debug = false
 
@@ -323,9 +324,15 @@ class NomsuCompiler
         else
             error("Invalid filetype for #{filename}", 0)
     
-    require_file: (filename)=>
+    use_file: (filename)=>
         loaded = @environment.LOADED
         if not loaded[filename]
+            for i,f in ipairs @use_stack
+                if f == filename
+                    loop = [@use_stack[j] for j=i,#@use_stack]
+                    insert loop, filename
+                    error("Circular import, this loops forever: #{concat loop, " -> "}")
+            insert @use_stack, filename
             loaded[filename] = @run_file(filename) or true
         return loaded[filename]
 
@@ -933,8 +940,8 @@ class NomsuCompiler
 
         @define_compile_action "use %filename", get_line_no!, (_filename)->
             filename = nomsu\tree_to_value(_filename)
-            nomsu\require_file(filename)
-            return expr:"nomsu:require_file(#{repr filename});"
+            nomsu\use_file(filename)
+            return expr:"nomsu:use_file(#{repr filename});"
 
 -- Only run this code if this file was run directly with command line arguments, and not require()'d:
 if arg and debug.getinfo(2).func != require