diff --git a/src/executor.py b/src/executor.py
index 32ed2bd..c1ed52c 100644
--- a/src/executor.py
+++ b/src/executor.py
@@ -29,6 +29,9 @@ def __init__(self, ast):
             "xor": self.instruction_xor,
             "negate": self.instruction_negate,
             "not": self.instruction_not,
+            "equal": self.instruction_equal,
+            "greater": self.instruction_greater,
+            "lesser": self.instruction_lesser,
             "if": self.instruction_if,
             "while": self.instruction_while,
             "exit": lambda args, bindings: exit(self.resolve_value(args[0], bindings)),
@@ -112,7 +115,25 @@ def instruction_negate(self, args, bindings):
     def instruction_not(self, args, bindings):
         ((_, target),) = args
         old = bindings.resolve(target)
-        bindings.assign(target, 0 if old else 1)
+        bindings.assign(target, not old)
+
+    def instruction_equal(self, args, bindings):
+        ((_, target),) = args
+        argument = self.stack.pop()
+        old = bindings.resolve(target)
+        bindings.assign(target, old == argument)
+
+    def instruction_greater(self, args, bindings):
+        ((_, target),) = args
+        argument = self.stack.pop()
+        old = bindings.resolve(target)
+        bindings.assign(target, old > argument)
+
+    def instruction_lesser(self, args, bindings):
+        ((_, target),) = args
+        argument = self.stack.pop()
+        old = bindings.resolve(target)
+        bindings.assign(target, old < argument)
 
     def instruction_if(self, args, bindings):
         for index in range(0, len(args) - 1, 2):
@@ -183,6 +204,9 @@ def resolve_value(self, value, bindings: Bindings):
         if kind == "id":
             return bindings.resolve(content)
 
+        if kind == "boolean":
+            return content == "true"
+
         return content
 
     def invoke_subroutine(self, name, bindings: Bindings):
diff --git a/src/grammar.py b/src/grammar.py
index bcf48e0..cff9122 100644
--- a/src/grammar.py
+++ b/src/grammar.py
@@ -5,24 +5,28 @@
     program         = ws_0n subroutine (sp_0n br ws_0n subroutine)* ws_0n
     subroutine      = identifier ws_1n block
     block           = begin ws_1n (instruction (sp_0n br ws_0n instruction)*)? ws_1n end
-    instruction     = conditional / loop / stack / op / io / stop
-                        / identifier / halt / store / load
+    instruction     = conditional / loop / stack / op / io / stop / identifier
+                        / halt / store / load
 
-    conditional     = if sp_1n value ws_1n block (ws_1n elif sp_1n value ws_1n block)* (ws_1n else ws_1n block)?
+    conditional     = if sp_1n value ws_1n
+                        block (ws_1n elif sp_1n value ws_1n block)*
+                        (ws_1n else ws_1n block)?
     loop            = while sp_1n value ws_1n block
     stack           = (push sp_1n value) / (pop sp_1n identifier)
-    op              = (add / subtract / multiply / divide / and / or / xor / negate / not) sp_1n identifier
+    op              = (add / subtract / multiply / divide / and / or / xor
+                        / negate / not / equal / greater / lesser) sp_1n identifier
     io              = print sp_1n value
     halt            = exit sp_1n value
 
     value           = identifier / literal
-    literal         = integer / float / string
+    literal         = integer / float / string / boolean
 
     identifier      = !reserved ~r"[a-z][a-z0-9_]*"i
     
     integer         = ~r"-?(0|([1-9][0-9]*))"
     float           = ~r"-?(0|([1-9][0-9]*))\.[0-9]+"
     string          = quote string_text quote
+    boolean         = true / false
 
     quote           = "\""
     string_text     = ~r"([^\"\\]|\\.)*"
@@ -35,7 +39,8 @@
 
     reserved        = begin / end / stop / if / elif / else / while / push
                         / pop / add / subtract / multiply / divide / and
-                        / or / xor / not / print / exit / store / load
+                        / or / xor / not / print / exit / store / load / true
+                        / false / equal / greater / lesser
     begin           = ~r"begin"i / ~r"do"i
     exit            = ~r"exit"i
     end             = ~r"end"i
@@ -58,5 +63,10 @@
     print           = ~r"print"i
     store           = ~r"store"i
     load            = ~r"load"i
+    true            = ~r"true"i
+    false           = ~r"false"i
+    equal           = ~r"equal"i
+    greater         = ~r"greater"i
+    lesser          = ~r"lesser"i
     """
 )
diff --git a/src/visitor.py b/src/visitor.py
index ad0e7ad..8920c4d 100644
--- a/src/visitor.py
+++ b/src/visitor.py
@@ -69,7 +69,7 @@ def visit_io(self, _, visited_children):
     def visit_stop(self, _, __):
         return ("stop",)
 
-    def visit_halt(self, node, visited_children):
+    def visit_halt(self, _, visited_children):
         operation, _, status_code = visited_children
         return operation.text, status_code
 
@@ -89,6 +89,9 @@ def visit_integer(self, node, _):
     def visit_float(self, node, _):
         return "float", float(node.text)
 
+    def visit_boolean(self, node, _):
+        return "boolean", node.text
+
     def visit_identifier(self, node, _):
         return "id", node.text
 
diff --git a/tests/add.imp b/tests/add.imp
index 3851832..aa984a5 100644
--- a/tests/add.imp
+++ b/tests/add.imp
@@ -1,9 +1,15 @@
-main
-    begin
-        push -5
-        pop x
-        push 5
-        add x
-        exit x
-        exit 1
-    end
\ No newline at end of file
+main begin
+    push 37
+    pop x
+
+    push 5
+    add x
+    
+    push 42
+    equal x
+    
+    if x do
+        exit 0
+    end
+    exit 1
+end
\ No newline at end of file
diff --git a/tests/not.imp b/tests/not.imp
index c37798e..1355c0c 100644
--- a/tests/not.imp
+++ b/tests/not.imp
@@ -1,5 +1,5 @@
 main begin
-  push 1
+  push true
   pop x
   not x
   
@@ -7,7 +7,7 @@ main begin
     exit 1
   end
 
-  push 0
+  push false
   pop x
   not x