extmod/modure: Add ure.sub() function and method, and tests.

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

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

1 files changed, 61 insertions, 0 deletions

diff --git a/tests/extmod/ure_sub.py b/tests/extmod/ure_sub.py
new file mode 100644
index 000000000..4aeb8650a
--- /dev/null
+++ b/tests/extmod/ure_sub.py
@@ -0,0 +1,61 @@
+try:
+    import ure as re
+except ImportError:
+    try:
+        import re
+    except ImportError:
+        print('SKIP')
+        raise SystemExit
+
+try:
+    re.sub
+except AttributeError:
+    print('SKIP')
+    raise SystemExit
+
+
+def multiply(m):
+    return str(int(m.group(0)) * 2)
+
+print(re.sub("\d+", multiply, "10 20 30 40 50"))
+
+print(re.sub("\d+", lambda m: str(int(m.group(0)) // 2), "10 20 30 40 50"))
+
+def A():
+    return "A"
+print(re.sub('a', A(), 'aBCBABCDabcda.'))
+
+print(
+    re.sub(
+        r'def\s+([a-zA-Z_][a-zA-Z_0-9]*)\s*\(\s*\):', 
+        'static PyObject*\npy_\\1(void){\n  return;\n}\n', 
+        '\n\ndef myfunc():\n\ndef myfunc1():\n\ndef myfunc2():'
+    )
+) 
+
+print(
+    re.compile(
+         '(calzino) (blu|bianco|verde) e (scarpa) (blu|bianco|verde)'
+    ).sub(
+        r'\g<1> colore \2 con \g<3> colore \4? ...',
+        'calzino blu e scarpa verde'
+    )
+)
+
+# no matches at all
+print(re.sub('a', 'b', 'c'))
+
+# with maximum substitution count specified
+print(re.sub('a', 'b', '1a2a3a', 2))
+
+# invalid group
+try:
+    re.sub('(a)', 'b\\2', 'a')
+except:
+    print('invalid group')
+
+# invalid group with very large number (to test overflow in uPy)
+try:
+    re.sub('(a)', 'b\\199999999999999999999999999999999999999', 'a')
+except:
+    print('invalid group')