diff --git a/paynt/parser/prism_parser.py b/paynt/parser/prism_parser.py
index cdfa73523..d204ef72b 100644
--- a/paynt/parser/prism_parser.py
+++ b/paynt/parser/prism_parser.py
@@ -40,8 +40,7 @@ def read_prism(cls, sketch_path, properties_path, relative_error, discount_facto
         holes = None
         if len(hole_definitions) > 0:
             logger.info("processing hole definitions...")
-            prism, hole_expressions, holes = PrismParser.parse_holes(
-                prism, expression_parser, hole_definitions)
+            prism, hole_expressions, holes = PrismParser.parse_holes(prism, expression_parser, hole_definitions)
 
         specification = PrismParser.parse_specification(properties_path, relative_error, discount_factor, prism, holes)
 
@@ -74,18 +73,23 @@ def load_sketch_prism(cls, sketch_path):
             sketch_lines = f.readlines()
 
         # replace hole definitions with constants
-        hole_re = re.compile(r'^hole\s+(.*?)\s+(.*?)\s+in\s+\{(.*?)\};$')
+        hole_re_brace = re.compile(r'^\s*hole\s+(.*?)\s+(.*?)\s+in\s+\{(.*?)\}\s*;\s*$')
+        # hole_re_bracket = re.compile(r'^\s*hole\s+(.*?)\s+(.*?)\s+in\s+[(.*?)]\s+;\s+$')
         sketch_output = []
-        hole_definitions = {}
+        hole_definitions = []
         for line in sketch_lines:
-            match = hole_re.search(line)
-            if match is not None:
-                hole_type = match.group(1)
-                hole_name = match.group(2)
-                hole_options = match.group(3).replace(" ", "")
-                hole_definitions[hole_name] = hole_options
-                line = f"const {hole_type} {hole_name};\n"
-            sketch_output.append(line)
+            match = hole_re_brace.search(line)
+            if match is None:
+                sketch_output.append(line)
+                continue
+            hole_type = match.group(1)
+            hole_name = match.group(2)
+            hole_options = match.group(3).replace(" ", "")
+            hole_definitions.append( (hole_name,hole_type,hole_options) )
+            sketch_output.append(f"const {hole_type} {hole_name};\n")
+            sketch_output.append(f"const {hole_type} {hole_name}_MIN;\n")
+            sketch_output.append(f"const {hole_type} {hole_name}_MAX;\n")
+
 
         # store modified sketch to a temporary file
         tmp_path = sketch_path + str(uuid.uuid4())
@@ -110,8 +114,19 @@ def parse_holes(cls, prism, expression_parser, hole_definitions):
         # parse hole definitions
         holes = Holes()
         hole_expressions = []
-        for hole_name,definition in hole_definitions.items():
-            options = definition.split(",")
+        hole_min = []
+        hole_max = []
+        for hole_name,hole_type,hole_options in hole_definitions:
+            if ".." in hole_options:
+                assert hole_type == "int", "cannot use range-based definitions for non-integer hole types"
+                options = hole_options.split("..")
+                range_start = int(options[0])
+                range_end = int(options[1])
+                hole_min.append(range_start)
+                hole_max.append(range_end)
+                options = [str(o) for o in range(range_start,range_end+1)]
+            else:
+                options = hole_options.split(",")
             expressions = [expression_parser.parse(o) for o in options]
             hole_expressions.append(expressions)
 
@@ -120,9 +135,20 @@ def parse_holes(cls, prism, expression_parser, hole_definitions):
             hole = Hole(hole_name, options, option_labels)
             holes.append(hole)
 
+        # substitute constants used as min/max values of holes
+        hole_range_definitions = {}
+        for hole_index,hole in enumerate(holes): 
+            var_min = prism.get_constant(f"{hole.name}_MIN").expression_variable
+            hole_range_definitions[var_min] = expression_parser.parse(str(hole_min[hole_index]))
+            var_max = prism.get_constant(f"{hole.name}_MAX").expression_variable
+            hole_range_definitions[var_max] = expression_parser.parse(str(hole_max[hole_index]))
+        prism = prism.define_constants(hole_range_definitions)
+
         # check that all undefined constants are indeed the holes
-        undefined_constants = [c for c in prism.constants if not c.defined]
-        assert len(undefined_constants) == len(holes), "some constants were unspecified"
+        hole_names = [hole.name for hole in holes]
+        for c in prism.constants:
+            if not c.defined:
+                assert c.name in hole_names, f"constant {c.name} was not specified"
 
         # convert single-valued holes to a defined constant
         trivial_holes_definitions = {}