diff --git a/tests/test_multi_03.py b/tests/test_multi_03.py
index fd6bda1..55465f4 100644
--- a/tests/test_multi_03.py
+++ b/tests/test_multi_03.py
@@ -7,6 +7,7 @@ from ziffers import zparse
     [
         ("1 2 3", [[1, 2, 3], [0.25,0.25,0.25]]),
         ("q2 eq3 e.4", [[2, 3, 4], [0.25,0.375,0.1875]]),
+        ("{q9 e10 23}", [[9,10,23],[0.25,0.125,0.25]])
     ],
 )
 def test_multi_var(pattern: str, expected: list):
diff --git a/ziffers/classes/__init__.py b/ziffers/classes/__init__.py
index e5a65ad..d496915 100644
--- a/ziffers/classes/__init__.py
+++ b/ziffers/classes/__init__.py
@@ -1,3 +1,3 @@
 from .items import *
 from .root import *
-from .sequences import *
\ No newline at end of file
+from .sequences import *
diff --git a/ziffers/classes/items.py b/ziffers/classes/items.py
index b4478f3..c3ada80 100644
--- a/ziffers/classes/items.py
+++ b/ziffers/classes/items.py
@@ -1,7 +1,6 @@
 """ Ziffers item classes """
 from dataclasses import dataclass, field, asdict
 from math import floor
-import operator
 import random
 from ..scale import (
     note_from_pc,
@@ -149,6 +148,26 @@ class Event(Item):
 class Rest(Event):
     """Class for rests"""
 
+    def get_note(self):
+        """Getter for note"""
+        return None
+
+    def get_freq(self):
+        """Getter for freq"""
+        return None
+
+    def get_octave(self):
+        """Getter for octave"""
+        return None
+
+    def get_pitch_class(self):
+        """Getter for pitche"""
+        return None
+    
+    def get_pitch_bend(self):
+        """Getter for pitche"""
+        return None
+
 
 @dataclass
 class Measure(Item):
@@ -283,9 +302,16 @@ class RandomPitch(Event):
         Returns:
             int: Returns random pitch
         """
-        return random.randint(
-            0, get_scale_length(options.get("scale", "Major")) if options else 9
-        )
+        if options:
+            scale = options["scale"]
+            if isinstance(scale, str):
+                scale_length = get_scale_length(options.get("scale", "Major"))
+            else:
+                scale_length = len(scale)
+        else:
+            scale_length = 9
+
+        return random.randint(0, scale_length)
 
 
 @dataclass(kw_only=True)
@@ -604,14 +630,6 @@ class Operator(Item):
     value: ...
 
 
-@dataclass(kw_only=True)
-class Operation(Item):
-    """Class for lisp-like operations: (+ 1 2 3) etc."""
-
-    values: list
-    operator: operator
-
-
 @dataclass(kw_only=True)
 class Atom(Item):
     """Class for evaluable atoms"""
diff --git a/ziffers/classes/root.py b/ziffers/classes/root.py
index 5529f28..165914a 100644
--- a/ziffers/classes/root.py
+++ b/ziffers/classes/root.py
@@ -3,7 +3,7 @@
 from dataclasses import dataclass, field
 from itertools import islice, cycle
 from ..defaults import DEFAULT_OPTIONS
-from .items import Item, Pitch, Chord, Event
+from .items import Item, Pitch, Chord, Event, Rest
 from .sequences import Sequence, Subdivision
 
 
@@ -32,7 +32,7 @@ class Ziffers(Sequence):
 
     def __len__(self):
         return len(self.evaluated_values)
-    
+
     def __iter__(self):
         return self
 
@@ -107,15 +107,15 @@ class Ziffers(Sequence):
         return [
             val.get_pitch_class()
             for val in self.evaluated_values
-            if isinstance(val, (Pitch, Chord))
+            if isinstance(val, (Pitch, Chord, Rest))
         ]
-    
+
     def pitch_bends(self) -> list[int]:
         """Return list of pitch bend values"""
         return [
             val.get_pitch_bend()
             for val in self.evaluated_values
-            if isinstance(val, (Pitch, Chord))
+            if isinstance(val, (Pitch, Chord, Rest))
         ]
 
     def notes(self) -> list[int]:
@@ -123,7 +123,7 @@ class Ziffers(Sequence):
         return [
             val.get_note()
             for val in self.evaluated_values
-            if isinstance(val, (Pitch, Chord))
+            if isinstance(val, (Pitch, Chord, Rest))
         ]
 
     def durations(self) -> list[float]:
@@ -133,10 +133,12 @@ class Ziffers(Sequence):
             for val in self.evaluated_values
             if isinstance(val, Event)
         ]
-    
+
     def total_duration(self) -> float:
         """Return total duration"""
-        return sum([val.duration for val in self.evaluated_values if isinstance(val, Event)])
+        return sum(
+            [val.duration for val in self.evaluated_values if isinstance(val, Event)]
+        )
 
     def total_beats(self) -> float:
         """Return total beats"""
@@ -161,7 +163,7 @@ class Ziffers(Sequence):
         return [
             val.get_octave()
             for val in self.evaluated_values
-            if isinstance(val, (Pitch, Chord))
+            if isinstance(val, (Pitch, Chord, Rest))
         ]
 
     def freqs(self) -> list[int]:
@@ -169,9 +171,9 @@ class Ziffers(Sequence):
         return [
             val.get_freq()
             for val in self.evaluated_values
-            if isinstance(val, (Pitch, Chord))
+            if isinstance(val, (Pitch, Chord, Rest))
         ]
-    
+
     def collect(self, num: int = None, keys: str | list = None) -> list:
         """Collect n items from parsed Ziffers"""
         if num is None:
diff --git a/ziffers/classes/sequences.py b/ziffers/classes/sequences.py
index 2c42167..5b66b17 100644
--- a/ziffers/classes/sequences.py
+++ b/ziffers/classes/sequences.py
@@ -4,8 +4,9 @@ from itertools import product
 from math import floor
 from types import LambdaType
 from copy import deepcopy
+import operator
 from ..defaults import DEFAULT_OPTIONS
-from ..common import cyclic_zip, euclidian_rhythm
+from ..common import cyclic_zip, euclidian_rhythm, flatten
 from ..scale import note_from_pc, midi_to_freq
 from .items import (
     Meta,
@@ -31,7 +32,7 @@ from .items import (
     Modification,
     Whitespace,
     Sample,
-    SampleList
+    SampleList,
 )
 
 
@@ -46,6 +47,8 @@ def resolve_item(item: Meta, options: dict):
         elif isinstance(item, Subdivision):
             item.evaluate_values(options)
             yield item
+        elif isinstance(item, Eval):
+            yield from item.evaluate_values(options)
         else:
             yield from item.evaluate_tree(options)
     elif isinstance(item, VariableAssignment):
@@ -66,14 +69,14 @@ def resolve_item(item: Meta, options: dict):
                         run=opt_item,
                         text=item.text,
                         kwargs=(options | item.local_options),
-                        local_options=item.local_options
+                        local_options=item.local_options,
                     )
                 elif isinstance(opt_item, str):
                     yield Sample(
                         name=opt_item,
                         text=item.text,
                         kwargs=(options | item.local_options),
-                        local_options=item.local_options
+                        local_options=item.local_options,
                     )
                 variable = deepcopy(opt_item)
                 yield from resolve_item(variable, options)
@@ -90,7 +93,7 @@ def resolve_item(item: Meta, options: dict):
                             run=opt_item,
                             text=var.text,
                             kwargs=(options | var.local_options),
-                            local_options=var.local_options
+                            local_options=var.local_options,
                         )
                     )
                 elif isinstance(opt_item, str):
@@ -99,7 +102,7 @@ def resolve_item(item: Meta, options: dict):
                             name=opt_item,
                             text=var.text,
                             kwargs=(options | var.local_options),
-                            local_options=var.local_options
+                            local_options=var.local_options,
                         )
                     )
                 elif isinstance(opt_item, Sequence):
@@ -343,7 +346,7 @@ class Subdivision(Sequence):
             if isinstance(item, Event):
                 if duration is not None:
                     item.duration = new_d
-                    item.beat = new_d*4
+                    item.beat = new_d * 4
                 yield item
 
 
@@ -373,6 +376,8 @@ class ListOperation(Sequence):
                         flattened_list.extend(list(item.evaluate_durations()))
                     elif isinstance(item, RepeatedListSequence):
                         flattened_list.extend(list(item.resolve_repeat(options)))
+                    elif isinstance(item, Eval):
+                        flattened_list.extend(item.evaluate_values(options))
                     else:
                         flattened_list.append(_filter_operation(item, options))
                 elif isinstance(item, Cyclic):
@@ -543,13 +548,43 @@ class ListOperation(Sequence):
 class Eval(Sequence):
     """Class for evaluation notation"""
 
-    result: ... = None
     wrap_start: str = field(default="{", repr=False)
     wrap_end: str = field(default="}", repr=False)
 
-    def __post_init__(self):
-        super().__post_init__()
-        self.result = eval(self.text)
+    # def __post_init__(self):
+    #    self.text = "".join([val.text for val in flatten(self.values)])
+    #   super().__post_init__()
+
+    def evaluate_values(self, options):
+        operations = [val for val in self.values if isinstance(val, (Operation, Rest))]
+        eval_values = []
+        for val in operations:
+            if isinstance(val,Operation):
+                eval_values.append(Pitch(pitch_class=val.evaluate(), kwargs=options | val.local_options))
+            else:
+                eval_values.append(val)
+
+        self.evaluated_values = eval_values
+
+        return self.evaluated_values
+
+
+@dataclass(kw_only=True)
+class LispOperation(Sequence):
+    """Class for lisp-like operations: (+ 1 2 3) etc."""
+
+    values: list
+    operator: operator
+
+
+@dataclass(kw_only=True)
+class Operation(Sequence):
+    """Class for sequential operations"""
+
+    values: list
+
+    def evaluate(self):
+        return eval(self.text)
 
 
 @dataclass(kw_only=True)
@@ -588,6 +623,8 @@ class RepeatedSequence(Sequence):
                 elif isinstance(item, Subdivision):
                     item.evaluate_values(options)
                     yield item
+                elif isinstance(item, Eval):
+                    yield from item.evaluate_values(options)
                 else:
                     yield from item
             elif isinstance(item, Cyclic):
diff --git a/ziffers/common.py b/ziffers/common.py
index 285828f..17fe4e3 100644
--- a/ziffers/common.py
+++ b/ziffers/common.py
@@ -2,6 +2,7 @@
 import re
 from copy import deepcopy
 
+
 def flatten(arr: list) -> list:
     """Flattens array"""
     return (
@@ -23,14 +24,16 @@ def rotate(arr, k):
         arr = arr[-k:] + arr[:-k]
     return arr
 
-def repeat_text(pos,neg,times):
+
+def repeat_text(pos, neg, times):
     """Helper to repeat text"""
-    if times>0:
-        return pos*times
-    if times<0:
-        return neg*abs(times)
+    if times > 0:
+        return pos * times
+    if times < 0:
+        return neg * abs(times)
     return ""
 
+
 def sum_dict(arr: list[dict]) -> dict:
     """Sums a list of dicts: [{a:3,b:3},{b:1}] -> {a:3,b:4}"""
     result = arr[0]
@@ -110,4 +113,4 @@ def cyclic_zip(first: list, second: list) -> list:
     f_length = len(first)
     for i in range(s_length):
         result.append([first[i % f_length], second[i]])
-    return [deepcopy(item) for sublist in result for item in sublist]
\ No newline at end of file
+    return [deepcopy(item) for sublist in result for item in sublist]
diff --git a/ziffers/generators.py b/ziffers/generators.py
new file mode 100644
index 0000000..e09bf44
--- /dev/null
+++ b/ziffers/generators.py
@@ -0,0 +1,35 @@
+"""Collection of generators"""
+
+
+# Sieve of Eratosthenes
+# Based on code by David Eppstein, UC Irvine, 28 Feb 2002
+# http://code.activestate.com/recipes/117119/
+def gen_primes():
+    """Generate an infinite sequence of prime numbers."""
+    # Maps composites to primes witnessing their compositeness.
+    # This is memory efficient, as the sieve is not "run forward"
+    # indefinitely, but only as long as required by the current
+    # number being tested.
+    sieve = {}
+
+    # The running integer that's checked for primeness
+    current = 2
+
+    while True:
+        if current not in sieve:
+            # current is a new prime.
+            # Yield it and mark its first multiple that isn't
+            # already marked in previous iterations
+            yield current
+            sieve[current * current] = [current]
+        else:
+            # current is composite. sieve[current] is the list of primes that
+            # divide it. Since we've reached current, we no longer
+            # need it in the map, but we'll mark the next
+            # multiples of its witnesses to prepare for larger
+            # numbers
+            for composite in sieve[current]:
+                sieve.setdefault(composite + current, []).append(composite)
+            del sieve[current]
+
+        current += 1
diff --git a/ziffers/mapper.py b/ziffers/mapper.py
index c949709..0443838 100644
--- a/ziffers/mapper.py
+++ b/ziffers/mapper.py
@@ -1,8 +1,7 @@
 """ Lark transformer for mapping Lark tokens to Ziffers objects """
 import random
-from math import log, pow
 from lark import Transformer, Token
-from .scale import cents_to_semitones, ratio_to_cents
+from .scale import cents_to_semitones, ratio_to_cents, monzo_to_cents
 from .classes.root import Ziffers
 from .classes.sequences import (
     Sequence,
@@ -13,6 +12,8 @@ from .classes.sequences import (
     Euclid,
     Subdivision,
     Eval,
+    Operation,
+    LispOperation,
 )
 from .classes.items import (
     Whitespace,
@@ -29,7 +30,6 @@ from .classes.items import (
     RandomInteger,
     Range,
     Operator,
-    Operation,
     Atom,
     Integer,
     VariableAssignment,
@@ -138,6 +138,11 @@ class ZiffersTransformer(Transformer):
         text_value = items[0].value.replace("T", "10").replace("E", "11")
         return {"pitch_class": int(text_value), "text": items[0].value}
 
+    def escaped_pitch(self, items):
+        """Return escaped pitch"""
+        val = items[0].value[1:-1]
+        return {"pitch_class": int(val), "text": val}
+
     def prefix(self, items):
         """Return prefix"""
         return items[0]
@@ -305,8 +310,7 @@ class ZiffersTransformer(Transformer):
 
     def eval(self, items):
         """Parse eval"""
-        val = items[0]
-        return Eval(values=val)
+        return Eval(values=items)
 
     def sub_operations(self, items):
         """Returns list of operations"""
@@ -314,12 +318,16 @@ class ZiffersTransformer(Transformer):
 
     def operation(self, items):
         """Return partial eval operations"""
-        return flatten(items)
+        if isinstance(items[0], dict):
+            local_opts = items[0]
+            del local_opts["text"]
+            return Operation(values=flatten(items[1:]), local_options=items[0])
+        return Operation(values=flatten(items))
 
     def atom(self, token):
         """Return partial eval item"""
         val = token[0].value
-        return Atom(value=val, text=val)
+        return Atom(value=val, text=str(val))
 
     # Variable assignment
 
@@ -340,6 +348,7 @@ class ZiffersTransformer(Transformer):
         return items[0].value
 
     def variable(self, items):
+        """Return variable"""
         if len(items) > 1:
             prefixes = sum_dict(items[0:-1])
             text_prefix = prefixes.pop("text")
@@ -405,9 +414,10 @@ class ZiffersTransformer(Transformer):
                 )
             return seq
 
-    def NUMBER(self, token):
-        """Parse integer"""
-        val = token.value
+    def integer(self, items):
+        """Parses integer from single ints"""
+        concatted = sum_dict(items)
+        val = concatted["text"]
         return Integer(text=val, value=int(val))
 
     def number(self, item):
@@ -422,7 +432,7 @@ class ZiffersTransformer(Transformer):
         """Parse lisp like list operation"""
         op = items[0]
         values = items[1:]
-        return Operation(
+        return LispOperation(
             operator=op,
             values=values,
             text="(+" + "".join([v.text for v in values]) + ")",
@@ -433,6 +443,11 @@ class ZiffersTransformer(Transformer):
         val = token[0].value
         return Operator(text=val, value=OPERATORS[val])
 
+    def list_operator(self, token):
+        """Parse list operator"""
+        val = token[0].value
+        return Operator(text=val, value=OPERATORS[val])
+
     def list_items(self, items):
         """Parse sequence"""
         return Sequence(values=items)
@@ -483,44 +498,67 @@ class ZiffersTransformer(Transformer):
 
 # pylint: disable=locally-disabled, unused-argument, too-many-public-methods, invalid-name, eval-used
 class ScalaTransformer(Transformer):
+    """Transformer for scala scales"""
+
     def lines(self, items):
-        cents = [ratio_to_cents(item) if isinstance(item,int) else item for item in items]
+        """Transforms cents to semitones"""
+        cents = [
+            ratio_to_cents(item) if isinstance(item, int) else item for item in items
+        ]
         return cents_to_semitones(cents)
 
     def operation(self, items):
+        """Get operation"""
         # Safe eval. Items are pre-parsed.
         val = eval("".join(str(item) for item in items))
         return val
 
     def operator(self, items):
+        """Get operator"""
         return items[0].value
 
     def sub_operations(self, items):
+        """Get sub-operation"""
         return "(" + items[0] + ")"
 
-    def ratio(self, items):
-        ratio = items[0]/items[1]
+    def frac_ratio(self, items):
+        """Get ration as fraction"""
+        ratio = items[0] / items[1]
         return ratio_to_cents(ratio)
-    
+
+    def decimal_ratio(self, items):
+        """Get ratio as decimal"""
+        ratio = float(str(items[0]) + "." + str(items[1]))
+        return ratio_to_cents(ratio)
+
+    def monzo(self, items):
+        """Get monzo ratio"""
+        return monzo_to_cents(items)
+
     def edo_ratio(self, items):
-        ratio = pow(2,items[0]/items[1])
+        """Get EDO ratio"""
+        ratio = pow(2, items[0] / items[1])
         return ratio_to_cents(ratio)
-    
+
     def edji_ratio(self, items):
-        if len(items)>3:
-            power = items[2]/items[3]
+        """Get EDJI ratio"""
+        if len(items) > 3:
+            power = items[2] / items[3]
         else:
             power = items[2]
-        ratio = pow(power,items[0]/items[1])
+        ratio = pow(power, items[0] / items[1])
         return ratio_to_cents(ratio)
-    
+
     def int(self, items):
+        """Get integer"""
         return int(items[0].value)
-    
+
     def float(self, items):
+        """Get float"""
         return float(items[0].value)
-        
+
     def random_int(self, items):
+        """Get random integer"""
 
         def _rand_between(start, end):
             return random.randint(min(start, end), max(start, end))
@@ -529,8 +567,9 @@ class ScalaTransformer(Transformer):
         end = items[1]
         rand_val = _rand_between(start, end)
         return rand_val
-    
+
     def random_decimal(self, items):
+        """Get random decimal"""
 
         def _rand_between(start, end):
             return random.uniform(min(start, end), max(start, end))
diff --git a/ziffers/scale.py b/ziffers/scale.py
index 5bf359c..3ef1836 100644
--- a/ziffers/scale.py
+++ b/ziffers/scale.py
@@ -2,7 +2,9 @@
 #!/usr/bin/env python3
 # pylint: disable=locally-disabled, no-name-in-module
 import re
-from math import log2, floor, log
+from math import log2
+from itertools import islice
+from .generators import gen_primes
 from .common import repeat_text
 from .defaults import (
     SCALES,
@@ -70,7 +72,7 @@ def note_name_to_midi(name: str) -> int:
     return 12 + octave * 12 + interval + modifier
 
 
-def get_scale(name: str) -> list[int]:
+def get_scale(scale: str) -> list[int]:
     """Get a scale from the global scale list
 
     Args:
@@ -79,7 +81,10 @@ def get_scale(name: str) -> list[int]:
     Returns:
         list: List of intervals in the scale
     """
-    scale = SCALES.get(name.lower().capitalize(), SCALES["Ionian"])
+    if isinstance(scale, (list, tuple)):
+        return scale
+
+    scale = SCALES.get(scale.lower().capitalize(), SCALES["Ionian"])
     return scale
 
 
@@ -102,7 +107,11 @@ def get_scale_notes(name: str, root: int = 60, num_octaves: int = 1) -> list[int
 
 
 def get_chord_from_scale(
-    degree: int, root: int = 60, scale: str = "Major", num_notes: int = 3, skip: int = 2
+    degree: int,
+    root: int = 60,
+    scale: str | tuple = "Major",
+    num_notes: int = 3,
+    skip: int = 2,
 ) -> list[int]:
     """Generate chord from the scale by skipping notes
 
@@ -116,12 +125,17 @@ def get_chord_from_scale(
     Returns:
         list[int]: List of midi notes
     """
-    num_of_octaves = ((num_notes * skip + degree) // get_scale_length(scale)) + 1
+    if isinstance(scale, str):
+        scale_length = get_scale_length(scale)
+    else:
+        scale_length = len(scale)
+
+    num_of_octaves = ((num_notes * skip + degree) // scale_length) + 1
     scale_notes = get_scale_notes(scale, root, num_of_octaves)
     return scale_notes[degree - 1 :: skip][:num_notes]
 
 
-def get_scale_length(name: str) -> int:
+def get_scale_length(scale: str) -> int:
     """Get length of the scale
 
     Args:
@@ -130,8 +144,10 @@ def get_scale_length(name: str) -> int:
     Returns:
         int: Length of the scale
     """
-    scale = SCALES.get(name.lower().capitalize(), SCALES["Ionian"])
-    return len(scale)
+    if isinstance(scale, (list, tuple)):
+        return len(scale)
+
+    return len(SCALES.get(scale.lower().capitalize(), SCALES["Ionian"]))
 
 
 # pylint: disable=locally-disabled, too-many-arguments
@@ -271,9 +287,9 @@ def midi_to_pitch_class(note: int, key: str | int, scale: str) -> dict:
     Returns:
         tuple: Returns dict containing pitch-class values
     """
-    pitch_class = note % 12
+    pitch_class = int(note % 12)  # Cast to int "fixes" microtonal scales
     octave = midi_to_octave(note) - 5
-    if scale.upper() == "CHROMATIC":
+    if isinstance(scale, str) and scale.upper() == "CHROMATIC":
         return {"text": str(pitch_class), "pitch_class": pitch_class, "octave": octave}
 
     sharps = ["0", "#0", "1", "#1", "2", "3", "#3", "4", "#4", "5", "#5", "6"]
@@ -319,7 +335,11 @@ def chord_from_degree(
     """
     root = note_name_to_midi(root) if isinstance(root, str) else root
 
-    if name is None and scale.lower().capitalize() == "Chromatic":
+    if (
+        name is None
+        and isinstance(scale, str)
+        and scale.lower().capitalize() == "Chromatic"
+    ):
         name = "major"
 
     if name:
@@ -387,6 +407,32 @@ def cents_to_semitones(cents: list) -> tuple[float]:
         semitone_scale.append(semitone_interval)
     return tuple(semitone_scale)
 
+
 def ratio_to_cents(ratio: float) -> float:
     """Transform ratio to cents"""
-    return 1200.0 * log(float(ratio), 2)
+    return 1200.0 * log2(float(ratio))
+
+
+def monzo_to_cents(monzo) -> float:
+    """
+    Convert a monzo to cents using the prime factorization method.
+
+    Args:
+        monzo (list): A list of integers representing the exponents of the prime factorization
+
+    Returns:
+        float: The value in cents
+    """
+    # Calculate the prime factors of the indices in the monzo
+    max_index = len(monzo)
+    primes = list(islice(gen_primes(), max_index + 1))
+
+    # Product of the prime factors raised to the corresponding exponents
+    ratio = 1
+    for i in range(max_index):
+        ratio *= primes[i] ** monzo[i]
+
+    # Frequency ratio to cents
+    cents = 1200 * log2(ratio)
+
+    return cents
diff --git a/ziffers/spec/scala.lark b/ziffers/spec/scala.lark
index a42dba6..fddc894 100644
--- a/ziffers/spec/scala.lark
+++ b/ziffers/spec/scala.lark
@@ -1,20 +1,24 @@
 ?root: lines
 
-lines: (number | operation | ratio | edo_ratio | edji_ratio)+
+lines: (number | ratio | monzo | operation)+
 
-operation: (number | ratio) (operator ((number | ratio) | sub_operations | operation))+
-ratio: (int | random_int) "/" (int | random_int)
-edo_ratio: (int | random_int) "\\" (int | random_int)
-edji_ratio: (int | random_int) "\\" (int | random_int) "<" (int | random_int) "/"? (int | random_int)? ">"
-!operator: "+" | "-" | "*" | "%" | "&" | "|" | "<<" | ">>"
-sub_operations: "(" operation ")"
-
-// Signed number without EXP
 ?number: float | int | random_int | random_float
 random_int: "(" int "," int ")"
 random_float: "(" float "," float ")"
 float: /(-?[0-9]+\.[0-9]*)|(\.[0-9]+)/
-int: /[0-9]+/
+int: /-?[0-9]+/
+
+?ratio: frac_ratio | edo_ratio | edji_ratio | decimal_ratio
+frac_ratio: (int | random_int) "/" (int | random_int)
+edo_ratio: (int | random_int) "\\" (int | random_int)
+edji_ratio: (int | random_int) "\\" (int | random_int) "<" (int | random_int) "/"? (int | random_int)? ">"
+decimal_ratio: int "," int
+
+monzo: "[" int+ ">"
+
+operation: (number | ratio | monzo) (operator ((number | ratio | monzo) | sub_operations | operation))+
+!operator: "+" | "-" | "*" | "%" | "&" | "|" | "<<" | ">>"
+sub_operations: "(" operation ")"
 
 %import common.WS
 %ignore WS
\ No newline at end of file
diff --git a/ziffers/spec/ziffers.lark b/ziffers/spec/ziffers.lark
index 0066d26..03466b9 100644
--- a/ziffers/spec/ziffers.lark
+++ b/ziffers/spec/ziffers.lark
@@ -3,7 +3,7 @@
     sequence: (pitch_class | repeat_item | assignment | variable | variablelist | rest | dur_change | oct_mod | oct_change | WS | measure | chord | named_roman | cycle | random_integer | random_pitch | random_percent | range | list | repeated_list | lisp_operation | list_op | subdivision | eval | euclid | repeat)*
     
     // Pitch classes
-    pitch_class: prefix* pitch
+    pitch_class: prefix* (pitch | escaped_pitch)
     prefix: (octave | duration_chars | escaped_decimal | escaped_octave | modifier)
     pitch: /-?[0-9TE]/
     escaped_decimal: "<" decimal ">"
@@ -39,10 +39,9 @@
     invert: /%-?[0-9][0-9]*/
   
     // Valid as integer
-    number: NUMBER | random_integer | cycle
-    
-    // CYCLIC NUMBERS NOT IN USE. NUMBERS MUST BE VALIDATED FROM FULL CYCLES!
-    // cyclic_number: "<" number (WS number)* ">"
+    number: integer | random_integer | cycle
+    integer: pitch+
+    escaped_pitch: /{-?[0-9]+}/
 
     // Repeats
     repeat: "[:" sequence ":" [number] "]"
@@ -53,10 +52,12 @@
     repeated_list: prefix* "(:" sequence ":" [number] ")"
 
     // Right recursive list operation
-    list_op: list (operator right_op)+
+    list_op: list ((operator | list_operator) right_op)+
     right_op: list | number
-    //operator: "+" | "-" | "*" | "%" | "&" | "|" | "<<" | ">>" | "@" | "#"
-    operator: /([\+\-\*\/%\|\&]|<<|>>|@|#|<>)/
+    // Operators that work only on lists: | << >>
+    list_operator: /(\||<<|>>|<>|#|@)(?=[(\d])/
+    // Common operators that works with numbers 3+5 3-5 etc.
+    operator: /([\+\-\*\/%\&])/
 
     // Euclidean cycles
     // TODO: Support randomization etc.
@@ -88,13 +89,9 @@
     random_percent: /(%)(?!\d)/
 
     // Rules for evaluating clauses inside {}
-    // TODO: Support for parenthesis?
-    eval: "{" operation+ "}"
-    operation: atom (operator (sub_operations | operation))*
+    eval: "{" ((operation | rest) WS?)+ "}"
+    operation: prefix? atom (operator (sub_operations | operation))*
     sub_operations: "(" operation ")"
-    atom: (NUMBER | DECIMAL)
+    atom: number
 
-    %import common.NUMBER
-    //%import common.SIGNED_NUMBER
-    %import common.DECIMAL
     %import common.WS
\ No newline at end of file