From 9804f3d636a6c074a33d2e70ff8c0ee39b8f7ac9 Mon Sep 17 00:00:00 2001
From: Matthias Goerner <1239022+unhyperbolic@users.noreply.github.com>
Date: Sun, 18 Jan 2026 11:45:47 +0100
Subject: [PATCH] SnapPy app adding multiline input: allowing the body of,
 e.g., a for loop, to have multiple lines. That is, we do not run code after
 adding the first line, only after adding an empty line.

---
 python/tkterminal.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/python/tkterminal.py b/python/tkterminal.py
index 0f26a04c..349804d4 100644
--- a/python/tkterminal.py
+++ b/python/tkterminal.py
@@ -788,7 +788,8 @@ def interact_handle_input(self, cell, script=False):
             self._input_buffer = self.clean_code(cell)
         transformed_cell = self.IP.transform_cell(self._input_buffer)
         status, indent = self.IP.check_complete(transformed_cell)
-        self._current_indent = indent or ''
+        if indent:
+            self._current_indent = indent
         if status == 'incomplete':
             self.IP.more = True
             return
@@ -805,7 +806,15 @@ def interact_handle_input(self, cell, script=False):
         insert_line = int(self.text.index(Tk_.INSERT).split('.')[0])
         prompt_line = int(self.text.index('output_end').split('.')[0])
         tail = self.text.get('%d.%d' % (insert_line, self._prompt_size), Tk_.END)
-        if not tail.strip():
+        if tail.strip():
+            run_cell = False
+        else:
+            lines = cell.split('\n')
+            if len(lines) <= 2:
+                run_cell = True
+            else:
+                run_cell = not lines[-2][self._prompt_size:].strip()
+        if run_cell:
             self.text.tag_delete('history')
             self._input_buffer = self._input_buffer.rstrip() + '\n'
             self.text.delete(Tk_.INSERT, Tk_.END)