Learning Perl, Fourth Edition

Exercise

See Appendix A for an answer to the following exercise:

1. [30] Make a program that reads a list of strings from a file, one string per line, and then lets the user interactively enter patterns that may match some of the strings. For each pattern, the program should tell how many strings from the file matched, then which ones those were. Don’t re-read the file for each new pattern; keep the strings in memory. The filename may be hardcoded in the file. If a pattern is invalid (for example, if it has unmatched parentheses), the program should report that error and let the user continue trying patterns. When the user enters a blank line instead of a pattern, the program should quit. (If you need a file full of interesting strings to try matching, try the file sample_text in the files from the O’Reilly web site. See the Preface.)