diff --git a/src/rsprocess/grammar.lalrpop b/src/rsprocess/grammar.lalrpop
index ae77337..928631b 100644
--- a/src/rsprocess/grammar.lalrpop
+++ b/src/rsprocess/grammar.lalrpop
@@ -1,17 +1,20 @@
 use std::str::FromStr;
 use lalrpop_util::ParseError;
-use crate::rsprocess::{RSprocess, RSenvironment, RSassert, RSassertOp, RSBHML};
+use crate::rsprocess::{RSset, RSprocess, RSenvironment, RSassert, RSassertOp, RSBHML};
 
 grammar;
 
+// matches words (letter followed by numbers, letters or _)
 Literal = { r"[[:alpha:]][[:word:]]*" };
 
+// all numbers are i64
 Num: i64 = {
     r"[0-9]+" =>? i64::from_str(<>)
 	.map_err(|_| ParseError::User { error: "Number is too big" })
 };
 
-Comma<T, C>: Vec<T> = {
+// macro for matching sequence of patterns with C as separator
+Separeted<T, C>: Vec<T> = {
     <mut v:(<T> C)+> <e:T?> => match e {
 	None => v,
 	Some(e) => {
@@ -21,40 +24,44 @@ Comma<T, C>: Vec<T> = {
     }
 };
 
-pub Set: Vec<&'input str> = {
+// ----- SetParser -----
+pub Set: RSset<'input> = {
     <s: Set_of_entities> => s
 };
 
+// ----- ContextParser -----
 pub Context: Box<RSprocess<'input>> = {
     "[" "]" => Box::new(RSprocess::Nill),
     "[" <t: CTX_process>  "]" => Box::new(t),
-    "[" <t: Comma<CTX_process, ",">> "]" => Box::new(RSprocess::NondeterministicChoice{children: t})
+    "[" <t: Separeted<CTX_process, ",">> "]" => Box::new(RSprocess::NondeterministicChoice{children: t})
 };
 
 CTX_process: RSprocess<'input> = {
     <c: Set_of_entities> "." <k: CTX_process> => RSprocess::EntitySet{entities: c, next_process: Box::new(k)},
     "(" <k: CTX_process>  ")" => k,
-    "(" <k: Comma<CTX_process, "+">> ")" => RSprocess::Summation{children: k},
+    "(" <k: Separeted<CTX_process, "+">> ")" => RSprocess::Summation{children: k},
     "<" <n: Num> <k1: CTX_process> ">" "." <k: CTX_process> => RSprocess::WaitEntity{repeat: n, repeated_process: Box::new(k1), next_process: Box::new(k)},
     "nil" => RSprocess::Nill,
     <identifier: Literal> => RSprocess::ConstantIdentifier{identifier: identifier}
 };
 
-Set_of_entities: Vec<&'input str> = {
-    "{" "}" => vec![],
-    "{" <t: Literal> "}" => vec![t],
-    "{" <mut t: Comma<Literal, ",">> "}" => {t.sort(); t}
+Set_of_entities: RSset<'input> = {
+    "{" "}" => RSset::from(vec![]),
+    "{" <t: Literal> "}" => RSset::from(vec![t]),
+    "{" <t: Separeted<Literal, ",">> "}" => RSset::from(t)
 };
 
+// ----- EnvironmentParser -----
 pub Environment: Box<RSenvironment<'input>> = {
     "[" "]" => Box::new(RSenvironment::new()),
-    "[" <t: Comma<Env_term, ",">> "]" => Box::new(RSenvironment::from(t))
+    "[" <t: Separeted<Env_term, ",">> "]" => Box::new(RSenvironment::from(t))
 };
 
 Env_term: (&'input str, Box<RSprocess<'input>>) = {
     <identifier: Literal> "=" <k: CTX_process> => (identifier, Box::new(k))
 };
 
+// ----- AssertParser -----
 pub Assert: Box<RSassert<'input>> = {
     <f: Formula_Assert> => Box::new(f)
 };
@@ -62,8 +69,8 @@ pub Assert: Box<RSassert<'input>> = {
 Formula_Assert: RSassert<'input> = {
     "-" <f: Formula_Assert> => RSassert::Not(Box::new(f)),
     "(" <f1: Formula_Assert> "^" <f2: Formula_Assert> ")" => RSassert::Xor(Box::new(f1), Box::new(f2)),
-    "(" <f: Comma<Formula_Assert, "\\/">> ")" => RSassert::Or(f),
-    "(" <f: Comma<Formula_Assert, "/\\">> ")" => RSassert::And(f),
+    "(" <f: Separeted<Formula_Assert, "\\/">> ")" => RSassert::Or(f),
+    "(" <f: Separeted<Formula_Assert, "/\\">> ")" => RSassert::And(f),
     <c: Set_of_entities> "inW" => RSassert::Sub(c, RSassertOp::InW),
     <c: Set_of_entities> "inR" => RSassert::Sub(c, RSassertOp::InR),
     <c: Set_of_entities> "inI" => RSassert::Sub(c, RSassertOp::InI),
@@ -74,6 +81,7 @@ Formula_Assert: RSassert<'input> = {
     "?" "inP" => RSassert::NonEmpty(RSassertOp::InP),
 };
 
+// ----- BHMLParser -----
 pub BHML: Box<RSBHML<'input>> = {
     <g: Formula_BHML> => Box::new(g)
 };
@@ -81,8 +89,8 @@ pub BHML: Box<RSBHML<'input>> = {
 Formula_BHML: RSBHML<'input> = {
     "true" => RSBHML::True,
     "false" => RSBHML::False,
-    "(" <g: Comma<Formula_BHML, "\\/">> ")" => RSBHML::Or(g),
-    "(" <g: Comma<Formula_BHML, "/\\">> ")" => RSBHML::And(g),
+    "(" <g: Separeted<Formula_BHML, "\\/">> ")" => RSBHML::Or(g),
+    "(" <g: Separeted<Formula_BHML, "/\\">> ")" => RSBHML::And(g),
     "<" <f: Formula_Assert> ">" <g: Formula_BHML> => RSBHML::Diamond(Box::new(f), Box::new(g)),
     "[" <f: Formula_Assert> "]" <g: Formula_BHML> => RSBHML::Box(Box::new(f), Box::new(g)),
 };
diff --git a/src/rsprocess/mod.rs b/src/rsprocess/mod.rs
index e51ece5..5348efa 100644
--- a/src/rsprocess/mod.rs
+++ b/src/rsprocess/mod.rs
@@ -1,11 +1,40 @@
 use std::collections::BTreeMap;
 
+#[derive(Clone, Debug)]
+#[allow(dead_code)]
+pub struct RSset<'a> {
+    identifiers: Vec<&'a str>
+}
+
+impl<'a, const N: usize> From<[&'a str; N]> for RSset<'a> {
+    fn from(mut arr: [&'a str; N]) -> Self {
+	arr.sort();
+	RSset{identifiers: arr.to_vec()}
+    }
+}
+
+impl<'a> From<&[&'a str]> for RSset<'a> {
+    fn from(arr: &[&'a str]) -> Self {
+	let mut tmp = arr.to_vec();
+	tmp.sort();
+	RSset{identifiers: tmp}
+    }
+}
+
+impl<'a> From<Vec<&'a str>> for RSset<'a> {
+    fn from(mut arr: Vec<&'a str>) -> Self {
+	arr.sort();
+	RSset{identifiers: arr}
+    }
+}
+
+
 #[derive(Clone, Debug)]
 #[allow(dead_code)]
 pub enum RSprocess<'a> {
     Nill,
     ConstantIdentifier{identifier: &'a str},
-    EntitySet{entities: Vec<&'a str>, next_process: Box<RSprocess<'a>>},
+    EntitySet{entities: RSset<'a>, next_process: Box<RSprocess<'a>>},
     WaitEntity{repeat: i64, repeated_process: Box<RSprocess<'a>>, next_process: Box<RSprocess<'a>>},
     NondeterministicChoice{children: Vec<RSprocess<'a>>},
     Summation{children: Vec<RSprocess<'a>>}
@@ -58,7 +87,7 @@ pub enum RSassert<'a> {
     Xor(Box<RSassert<'a>>, Box<RSassert<'a>>),
     Or(Vec<RSassert<'a>>),
     And(Vec<RSassert<'a>>),
-    Sub(Vec<&'a str>, RSassertOp),
+    Sub(RSset<'a>, RSassertOp),
     NonEmpty(RSassertOp)
 }