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https://issues.apache.org/jira/browse/GROOVY-11655?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17949857#comment-17949857
]
ASF GitHub Bot commented on GROOVY-11655:
-----------------------------------------
paulk-asert commented on code in PR #2215:
URL: https://github.com/apache/groovy/pull/2215#discussion_r2076518594
##########
src/main/java/org/codehaus/groovy/runtime/StringGroovyMethods.java:
##########
@@ -1877,6 +1878,77 @@ public static StringBuilder leftShift(final
StringBuilder self, final Object val
return self;
}
+
//--------------------------------------------------------------------------
+ // make StringBuilder behaves like a stack of chars
+
+ /**
+ * Since StringBuilder is a basic dynamic container of chars, sometimes it
should
+ * behave like a stack of chars at the same time.
+ * stack's methods should have: push(), peek(), pop(), size(), isEmpty()
+ * <pre class="groovyTestCase">
+ * def st = new StringBuilder()
+ * // stack in cases:
+ * st.push('B')
+ * assert st.toString() == 'B'
+ * st.push('a')
+ * assert st.toString() == 'Ba'
+ * st.push('r')
+ * assert st.toString() == 'Bar'
+ * assert st.size() == 3
+ * assert st.isEmpty() == false
+ * // stack out cases:
+ * assert st.peek() == 'r' as char
+ * assert st.pop() == 'r' as char
+ * assert st.toString() == 'Ba'
+ * assert st.peek() == 'a' as char
+ * assert st.pop() == 'a' as char
+ * assert st.toString() == 'B'
+ * assert st.size() == 1
+ * assert st.isEmpty() == false
+ * assert st.pop() == 'B' as char
+ * assert st.isEmpty() == true
+ * </pre>
+ *
+ * @param self a StringBuilder obj
+ * @param ch a char to push in
+ * @return the StringBuilder obj self
+ * @since 5.0.0
+ */
+ public static StringBuilder push(final StringBuilder self, final char ch) {
+ Objects.requireNonNull(self);
+ self.append(ch);
+ return self;
+ }
+
+ public static StringBuilder push(final StringBuilder self, final String
ch) {
+ Objects.requireNonNull(self);
+ self.append(ch);
+ return self;
+ }
+
+ public static StringBuilder push(final StringBuilder self, final GString
ch) {
+ Objects.requireNonNull(self);
+ self.append(ch);
+ return self;
+ }
+
+ public static char peek(final StringBuilder self) {
+ Objects.requireNonNull(self);
+ assert self.length() > 0;
+ return self.charAt(self.length() - 1);
+ }
+
+ public static char pop(final StringBuilder self) {
+ char last = peek(self);
+ self.setLength(self.length() - 1);
+ return last;
+ }
+
+ public static int size(final StringBuilder self) {
Review Comment:
This is provided by #size(CharSequence) already.
> Create extension method to make StringBuilder like a stack
> ----------------------------------------------------------
>
> Key: GROOVY-11655
> URL: https://issues.apache.org/jira/browse/GROOVY-11655
> Project: Groovy
> Issue Type: New Feature
> Reporter: John
> Priority: Major
>
> for leetcode problem:
> [https://leetcode.com/problems/design-a-text-editor/description/]
> the java code below, suppose StringBuilder to be a contain of chars ,
> meanwhile as a stack.
>
> {code:java}
> class TextEditor {
> private final StringBuilder left = new StringBuilder();
> private final StringBuilder right = new StringBuilder();
> public void addText(String text) {
> left.append(text);
> }
> public int deleteText(int k) {
> k = Math.min(k, left.length());
> left.setLength(left.length() - k);
> return k;
> }
> public String cursorLeft(int k) {
> while (k > 0 && !left.isEmpty()) {
> right.append(left.charAt(left.length() - 1));
> left.setLength(left.length() - 1);
> k--;
> }
> return text();
> }
> public String cursorRight(int k) {
> while (k > 0 && !right.isEmpty()) {
> left.append(right.charAt(right.length() - 1));
> right.setLength(right.length() - 1);
> k--;
> }
> return text();
> }
> private String text() {
>
> return left.substring(Math.max(left.length() - 10, 0));
> }
> }
> {code}
>
>
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