Support peeking ahead multiple tokens

1 files changed, 20 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/tokeniser/TokenIteratorTests.java b/src/test/java/org/shedlang/compiler/tokeniser/TokenIteratorTests.java
index 315551ee..52d036a8 100644
--- a/src/test/java/org/shedlang/compiler/tokeniser/TokenIteratorTests.java
+++ b/src/test/java/org/shedlang/compiler/tokeniser/TokenIteratorTests.java
@@ -223,6 +223,26 @@ public class TokenIteratorTests {
         assertThat(tokens.peek(), equalTo(token(1, TokenType.IDENTIFIER, "x")));
     }
 
+    @Test
+    public void canPeekMultipleTokensAhead() {
+        var tokens = new TokenIterator<>(
+            List.of(
+                token(0, TokenType.SYMBOL, "!"),
+                token(1, TokenType.IDENTIFIER, "x"),
+                token(2, TokenType.SYMBOL, "!")
+            ),
+            token(3, TokenType.END, "")
+        );
+
+        assertThat(tokens.peek(0), equalTo(token(0, TokenType.SYMBOL, "!")));
+        assertThat(tokens.peek(1), equalTo(token(1, TokenType.IDENTIFIER, "x")));
+        assertThat(tokens.peek(2), equalTo(token(2, TokenType.SYMBOL, "!")));
+        tokens.skip(TokenType.SYMBOL);
+        assertThat(tokens.peek(0), equalTo(token(1, TokenType.IDENTIFIER, "x")));
+        assertThat(tokens.peek(1), equalTo(token(2, TokenType.SYMBOL, "!")));
+        assertThat(tokens.peek(2), equalTo(token(3, TokenType.END, "")));
+    }
+
     private Token<TokenType> token(int characterIndex, TokenType tokenType, String value) {
         return new Token<>(Sources.NULL, tokenType, value);
     }