Add helper method to cast datatypes from string

pfdl_scheduler/parser/pfdl_tree_visitor.py

@@ -358,12 +358,12 @@ def visitExpression(self, ctx: PFDLParser.ExpressionContext) -> Dict:
             ele = self.get_content(ctx.children[0])
             if isinstance(ele, List):
                 return ele
-            if helpers.is_int(ele):
-                return int(ele)
-            if helpers.is_float(ele):
-                return float(ele)
-            if helpers.is_boolean(ele):
-                return ele == "true"
+            elif not helpers.is_string(ele):
+                # strings should not appear here
+                casted_element = helpers.cast_element(ele)
+                # check if ele is a primitve datatype (number or bool)
+                if casted_element != ele:
+                    return casted_element
         if length == 2:
             un_op = self.get_content(ctx.children[0])
             ele = self.get_content(ctx.children[1])

pfdl_scheduler/utils/helpers.py

@@ -7,7 +7,7 @@
 """Helper functions used in the project (especially in the SemanticErrorChecker)."""
 
 # standard libraries
-from typing import Any, Dict, List
+from typing import Any, Dict, List, Union
 import operator
 
 # local sources
@@ -123,6 +123,23 @@ def is_int(string: str) -> bool:
         return True
 
 
+def cast_element(string: str) -> Union[str, int, float, bool]:
+    """Tries to cast the given string to a primitive datatype.
+
+    Returns:
+        The casted element if casting was successful, otherwise the input string
+    """
+    if is_int(string):
+        return int(string)
+    elif is_float(string):
+        return float(string)
+    elif is_boolean(string):
+        return string == "true"
+    elif is_string(string):
+        return string.replace('"', "")
+    return string
+
+
 def parse_operator(op: str) -> operator:
     """Parses a PFDL operator in form of a string into a Python executable operator func."""
     ops = {