runtime(python): Highlight f-string replacement fields in Python

Highlight f-string replacement fields, including

- Comments
- Debugging flags
- Conversion fields
- Format specifications
- Delimiters

Syntax inside fields will be addressed in a separate commit.

related: #10734
related: #14033
closes: #17784

Signed-off-by: Rob B <github@0x7e.net>
Signed-off-by: Zvezdan Petkovic <zpetkovic@acm.org>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/testdir/input/python_strings_bytes.py

@@ -99,6 +99,69 @@ and fields {1}, {2} and {1
     +
     2}"""
 
+# F-string replacement fields
+test = f"String is {
+    "one plus "
+    "two plus "
+    "three"}"
+test = f"Number is {
+    1 +
+    2 +
+    3}"
+test = f"abc{a # This is a comment }
+    + 1}"
+test = f"def{a # So is this :
+    + 2}"
+test = f"ghi{a # And this "
+    + 3}"
+test = f"He said his name is {name!r}."
+test = f"He said his name is {repr(name)}."
+test = f"result: {value:{width}}"
+test = f"result: {value:{width}.{precision}}"
+test = f"result: {value:{width:d}.{precision!s}}"
+test = f"result: {value:{options}{width}{grouping}{precision}{type}}"
+test = f"{number:#0x}"
+test = f"{number:+#0x}"
+test = f"{number:<+#0x}"
+test = f"{number: <+#0x}"
+test = f"{number:<#0x}"
+test = f"{number: <#0x}"
+test = f"{string=}"
+test = f"{string=!r}"
+test = f"{string=:20}"
+test = f"{string=!r:20}"
+test = f"{string = }"
+test = f"{string = !r}"
+test = f"{string = :20}"
+test = f"{string = !r:20}"
+test = f"abc {a["x"]} def"
+test = f"List contains:\n{"\n".join(a)}"
+test = f"Today's date is {datetime.now()}"
+test = f"Today's formatted date is {datetime.now():%Y-%m-%d %H:%M:%S}"
+test = f"Date is {datetime.datetime(2010, 7, 4, 12, 15, 58)}"
+test = f"Formatted date is {datetime.datetime(2010, 7, 4, 12, 15, 58):%Y-%m-%d %H:%M:%S}"
+test = f"Lambda returns {(lambda x: x**2)}"
+test = f"Zero padded lambda returns {(lambda x: x**2):09}"
+test = f"Space padded lambda returns {(lambda x: x**2):{width}}"
+test = f"List copy is {items[:]}"
+test = f"List slice is {items[1:]}"
+test = f"List slice is {items[:9]}"
+test = f"List elements are {items[:2:]}"
+test = f"Padded list copy is {items[:]:99}"
+test = f"Left-aligned list slice is {items[1:]:<99}"
+test = f"Right aligned list slice is {items[:9]:>99}"
+test = f"Center-aligned list elements are {items[:2:]:^99}"
+test = f"Expression is {x == 1}"
+test = f"Expression is {x != 1}"
+test = f"Expression is {(x := 1)}"
+test = f"Debug expression is {x == 1=}"
+test = f"Debug expression is {x != 1=}"
+test = f"Debug expression is {(x := 1)=}"
+test = f"List comprehension returns { [x**2 for x in range(10)] }"
+test = f"Padded list comprehension returns { [x**2 for x in range(10)] :99}"
+test = f"Dict comprehension returns { {x: x**2 for x in range(10)} }"
+test = f"Padded dict comprehension returns { {x: x**2 for x in range(10)} :99}"
+
 # Bytes
 test = b'Bytes with escapes \' and \" and \t'
 test = B"Bytes with escapes \040 and \xFF"