#
# Pattern matching demo program
#
# Matt Bishop, MHI 289I, Fall 2020
#
import re
import sys

#
# loop until end of file
#
while True:
    #
    # read in the pattern
    #
    try:
        pat = input("Pattern: ")
    except EOFError:
        break
    except Exception as msg:
        print(msg)
        continue
    #
    # now loop, matching strings (or not)
    #
    while True:
        #
        # read in a string
        #
        try:
            print("The pattern is:", pat)
            text = input("Text to match: ")
        except EOFError:
            sys.exit(0)
        except Exception as msg:
            print(msg)
            continue
        #
        # now do the matching
        #
        print("Does it match the begining of the string? ", end='')
        m = re.match(pat, text)
        if m:
            print("Yes")
            print("Here's the string it matched:", m.group())
            print("Here's the character positions it spans:", m.span())
            print("Here's the character position where it begins:", m.start())
            print("Here's the character position where it ends:", m.end())
        else:
            print("No")
            print("Does it match anywhere in the string? ", end='')
            n = re.search(pat, text)
            if n:
                print("Yes")
                print("Here's the string it matched:", n.group())
                print("Here's the character positions it spans:", n.span())
                print("Here's the character position where it begins:", n.start())
                print("Here's the character position where it ends:", n.end())
            else:
                print("No")
        print("Here are all the matches: ", end='')
        print(re.findall(pat, text))