bearophile wrote:
Andrei Alexandrescu:
I think the "g", "i", and "m" flags are popular enough if you've done any
amount of regex
programming.<
I think I don't like the "g".
-----------------------
To test an API it's often good to try to use it or compare it against similar
practical&common operations done with another language or library. So here I
show two examples in Python. You can try to translate such two operations with the
std.re of D2 to see how they become :-)
The first example shows the usage of a callable for re.sub() (in D it may be
called replace()).
Here replacer() is a user-defined function given to re.sub()/matchobj.sub()
that they call on each match.
Note that in Python functions are objects, so I have dynamically added to the replacer()
function an instance attribute named "counter". In D (and Python) you can do
the same thing creating a small class with counter attribute.
import re
def replacer(mobj):
replacer.counter += 1
return "REPL%02d" % replacer.counter
replacer.counter = 0
s1 = ".......TAG............TAG................TAG..........TAG....."
result =
".......REPL01............REPL02................REPL03..........REPL04..."
r = re.sub("TAG", replacer, s1)
assert r == result
----------
Excellent idea. Let's see:
uint counter;
string replacer(string) { return format("REPL%02d", counter++); }
auto s1 = ".......TAG............TAG................TAG..........TAG.....";
auto result =
".......REPL01............REPL02................REPL03..........REPL04...";
r = replace!(replacer)(s1, "TAG");
assert(r == result);
This is a little example of managing groups in Python:
import re
data = ">hello1 how are5 you?<"
patt = re.compile(r".*?(hello\d).*?(are\d).*")
patt.match(data).groups()
('hello1', 'are5')
auto data = ">hello1 how are5 you?<";
auto iter = match(data, regex(r".*?(hello\d).*?(are\d).*"));
foreach (i; 0 .. iter.engine.captures)
writeln(iter.capture[i]);
(notes that here all groups are found eagerly. If you want a lazy matching in
Python you have to use re.finditer() or matchobj.finditer()).
I may like a syntax similar to this, where opIndex() allows to find the matched
group:
patt.match(data)[0]
'hello1'
patt.match(data)[1]
'are5'
No go due to confusions with random-access ranges.
Andrei
