diff --git a/app/src/main/java/com/annimon/hotarufx/lexer/HotaruLexer.java b/app/src/main/java/com/annimon/hotarufx/lexer/HotaruLexer.java
index 8de3259..cc10f56 100644
--- a/app/src/main/java/com/annimon/hotarufx/lexer/HotaruLexer.java
+++ b/app/src/main/java/com/annimon/hotarufx/lexer/HotaruLexer.java
@@ -14,7 +14,7 @@ public class HotaruLexer extends Lexer {
     }
 
     private static final String TEXT_CHARS = "'\"";
-    private static final String OPERATOR_CHARS = "(){}=.,";
+    private static final String OPERATOR_CHARS = "(){}:=+-.,";
 
     private static final Map<String, HotaruTokenId> OPERATORS;
     static {
@@ -23,7 +23,10 @@ public class HotaruLexer extends Lexer {
         OPERATORS.put(")", HotaruTokenId.RPAREN);
         OPERATORS.put("{", HotaruTokenId.LBRACE);
         OPERATORS.put("}", HotaruTokenId.RBRACE);
+        OPERATORS.put(":", HotaruTokenId.COLON);
         OPERATORS.put("=", HotaruTokenId.EQ);
+        OPERATORS.put("+", HotaruTokenId.PLUS);
+        OPERATORS.put("-", HotaruTokenId.MINUS);
         OPERATORS.put(".", HotaruTokenId.DOT);
         OPERATORS.put(",", HotaruTokenId.COMMA);
     }
diff --git a/app/src/main/java/com/annimon/hotarufx/lexer/HotaruTokenId.java b/app/src/main/java/com/annimon/hotarufx/lexer/HotaruTokenId.java
index 1382bc9..00be239 100644
--- a/app/src/main/java/com/annimon/hotarufx/lexer/HotaruTokenId.java
+++ b/app/src/main/java/com/annimon/hotarufx/lexer/HotaruTokenId.java
@@ -11,10 +11,13 @@ public enum HotaruTokenId {
     TEXT(Category.STRING),
 
     EQ(Category.OPERATOR),
+    PLUS(Category.OPERATOR),
+    MINUS(Category.OPERATOR),
     LPAREN(Category.OPERATOR),
     RPAREN(Category.OPERATOR),
     LBRACE(Category.OPERATOR),
     RBRACE(Category.OPERATOR),
+    COLON(Category.OPERATOR),
     COMMA(Category.OPERATOR),
     DOT(Category.OPERATOR),
 
diff --git a/app/src/test/java/com/annimon/hotarufx/lexer/HotaruLexerTest.java b/app/src/test/java/com/annimon/hotarufx/lexer/HotaruLexerTest.java
index 2f33ec3..29b4d8e 100644
--- a/app/src/test/java/com/annimon/hotarufx/lexer/HotaruLexerTest.java
+++ b/app/src/test/java/com/annimon/hotarufx/lexer/HotaruLexerTest.java
@@ -76,14 +76,17 @@ class HotaruLexerTest {
 
     @Test
     void testTokenizeOperators() {
-        assertThat(t("(){}=,."), contains(
+        assertThat(t("(){}=+-,.:"), contains(
                 tokenId(HotaruTokenId.LPAREN),
                 tokenId(HotaruTokenId.RPAREN),
                 tokenId(HotaruTokenId.LBRACE),
                 tokenId(HotaruTokenId.RBRACE),
                 tokenId(HotaruTokenId.EQ),
+                tokenId(HotaruTokenId.PLUS),
+                tokenId(HotaruTokenId.MINUS),
                 tokenId(HotaruTokenId.COMMA),
-                tokenId(HotaruTokenId.DOT)
+                tokenId(HotaruTokenId.DOT),
+                tokenId(HotaruTokenId.COLON)
         ));
     }
 
@@ -118,11 +121,16 @@ class HotaruLexerTest {
 
     @Test
     void testStatements() {
-        assertThat(t("A = node()"), contains(
+        assertThat(t("A = node({x : 10})"), contains(
                 tokenId(HotaruTokenId.WORD),
                 tokenId(HotaruTokenId.EQ),
                 tokenId(HotaruTokenId.WORD),
                 tokenId(HotaruTokenId.LPAREN),
+                tokenId(HotaruTokenId.LBRACE),
+                tokenId(HotaruTokenId.WORD),
+                tokenId(HotaruTokenId.COLON),
+                tokenId(HotaruTokenId.NUMBER),
+                tokenId(HotaruTokenId.RBRACE),
                 tokenId(HotaruTokenId.RPAREN)
         ));
         assertThat(t("B.x = 100"), contains(