now allowing empty lines in the grammar, and created scaffold for bet…

…ter error messages

grammars/level1.txt

@@ -1,5 +1,5 @@
 start: program
-program: command ("\n" command)*
+program: command ("\n"+ command)* "\n"*
 command: "print " text -> print
                | "ask " text -> ask
                | "echo " text -> echo

grammars/level2.txt

@@ -1,5 +1,5 @@
 start: program
-program: command ("\n" command)*
+program: command ("\n"+ command)* "\n"*
 command: "print " ( list_access | (text punctuation)| text) (" " ( list_access | (text punctuation)| text) )*  -> print
          | text " is ask " textwithspaces punctuation* -> ask
          | text " is " text ((", "|",") text)+  -> assign_list

grammars/level3.txt

@@ -1,5 +1,5 @@
 start: program
-program: command ("\n" command)*
+program: command ("\n"+ command)* "\n"*
 command: "print " (quoted_text | list_access | var) (" " (quoted_text | list_access | var))*  -> print
          | text " is ask " textwithspaces punctuation* -> ask
          | text " is " text ((", "|",") text)+  -> assign_list

grammars/level4.txt

@@ -1,5 +1,5 @@
 start: program
-program: command ("\n" command)*
+program: command ("\n"+ command)* "\n"*
 command: "print " (quoted_text | list_access | var) (" " (quoted_text | list_access | var))*  -> print
          | "if " equality_check " " command " else " command -> ifelse
          | "if " equality_check " " command -> ifs //if cannot be used in Python, hence ifs

hedy.py

@@ -8,6 +8,7 @@ def __init__(self, message, **arguments):
         self.arguments = arguments
 
 
+
 class AllCommands(Transformer):
     #creates a list of all commands in a tree for further processing
     # it removes command and program nodes
@@ -325,9 +326,14 @@ def transpile(input_string, level):
         punctuation_symbols = ['!', '?', '.']
         level = int(level)
         parser = create_parser(level)
-        program_root = parser.parse(input_string).children[0]  # getting rid of the root could also be done in the transformer would be nicer
-        lookup_table = all_assignments(program_root)
-        flattened_tree = FlattenText().transform(program_root)
+        try:
+            program_root = parser.parse(input_string).children[0]  # getting rid of the root could also be done in the transformer would be nicer
+            lookup_table = all_assignments(program_root)
+            flattened_tree = FlattenText().transform(program_root)
+        except Exception as e:
+            # TODO: here we could translate Lark error messages into more sensible texts!
+            raise HedyException('Parse', level=level, parse_error=e.args[0])
+
         is_valid = IsValid().transform(program_root)
 
         if is_valid[0]:
@@ -360,6 +366,7 @@ def transpile(input_string, level):
     else:
         raise Exception('Levels 5 to 7 are not implemented yet')
 
+
 def execute(input_string):
     python = transpile(input_string)
     exec(python)

static/texts.json

@@ -18,7 +18,8 @@
             "Execute_error": "Er ging iets fout bij het uitvoeren van het programma."
         },
         "HedyErrorMessages": {
-            "Invalid": "{command} is geen command in Hedy level {level}."
+            "Invalid": "{command} is geen command in Hedy level {level}.",
+            "Parse": "De code die jij intypte is geen geldige Hedy code. De foutmelding is: {parse_error}"
         }
     },
     "en": {
@@ -40,7 +41,8 @@
             "Execute_error": "Something went wrong while running the program."
         },
         "HedyErrorMessages": {
-            "Invalid": "{command} is not a Hedy level {level} command."
+            "Invalid": "{command} is not a Hedy level {level} command.",
+            "Parse": "The code you entered is not valid Hedy code"
         }
     },
     "es": {
@@ -62,7 +64,8 @@
             "Execute_error": "Algo estuvo mal mientras se ejecuto el programa."
         },
         "HedyErrorMessages": {
-            "Invalid": "{command} no es un comando de Hedy en nivel {level}."
+            "Invalid": "{command} no es un comando de Hedy en nivel {level}.",
+            "Parse": "El servidor no puede traducir este programa de Hedy a Python."
         }
     }
 }

tests.py

@@ -27,14 +27,17 @@ class TestsLevel1(unittest.TestCase):
     def test_transpile_other(self):
         with self.assertRaises(Exception) as context:
             result = hedy.transpile("abc felienne 123", 1)
-
         self.assertEqual(str(context.exception), 'Invalid')
 
     def test_transpile_print(self):
         result = hedy.transpile("print Hallo welkom bij Hedy!", 1)
         self.assertEqual(result, "print('Hallo welkom bij Hedy!')")
         self.assertEqual(run_code(result), 'Hallo welkom bij Hedy!')
 
+    def test_transpile_empty(self):
+        with self.assertRaises(hedy.HedyException) as context:
+            result = hedy.transpile("", 1)
+
     def test_transpile_ask(self):
         result = hedy.transpile("ask wat is je lievelingskleur?", 1)
         self.assertEqual(result, "answer = input('wat is je lievelingskleur?')")