extmod/modure: Add match.span(), start() and end() methods, and tests.

This feature is controlled at compile time by
MICROPY_PY_URE_MATCH_SPAN_START_END, disabled by default.

Thanks to @dmazzella for the original patch for this feature; see #3770.

1 files changed, 40 insertions, 0 deletions

diff --git a/tests/extmod/ure_span.py b/tests/extmod/ure_span.py
new file mode 100644
index 000000000..50f44399c
--- /dev/null
+++ b/tests/extmod/ure_span.py
@@ -0,0 +1,40 @@
+# test match.span(), and nested spans
+
+try:
+    import ure as re
+except ImportError:
+    try:
+        import re
+    except ImportError:
+        print("SKIP")
+        raise SystemExit
+
+try:
+    m = re.match(".", "a")
+    m.span
+except AttributeError:
+    print('SKIP')
+    raise SystemExit
+
+
+def print_spans(match):
+    print('----')
+    try:
+        i = 0
+        while True:
+            print(match.span(i), match.start(i), match.end(i))
+            i += 1
+    except IndexError:
+        pass
+
+m = re.match(r'(([0-9]*)([a-z]*)[0-9]*)','1234hello567')
+print_spans(m)
+
+m = re.match(r'([0-9]*)(([a-z]*)([0-9]*))','1234hello567')
+print_spans(m)
+
+# optional span that matches
+print_spans(re.match(r'(a)?b(c)', 'abc'))
+
+# optional span that doesn't match
+print_spans(re.match(r'(a)?b(c)', 'bc'))