commit 2d2895ce14d94d50848f207db1463cc5af017319
Author: Nicolo P <nicolo.paraciani@cnr.it>
Date:   Sun Feb 13 16:25:20 2022 +0100

    Initial commit

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
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+*.swp
+test_f*.txt
+bin
+lib*
+*.cfg
+share
+*cache*
diff --git a/README.md b/README.md
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+++ b/README.md
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+# crapgrep
+
+Have you ever wanted to use a poorly-written, less-featured, slower replacement for an existing [powerful tool?](https://www.gnu.org/software/grep/)
+
+Then this is for you...
diff --git a/crapgrep/crapgrep.py b/crapgrep/crapgrep.py
new file mode 100644
index 0000000..a755f51
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+++ b/crapgrep/crapgrep.py
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+import exceptions
+import re
+import os
+import sys
+
+def print_usage():
+    usage = """
+Usage: pygrep.py [OPTIONS]... PATTERN [FILE]...
+
+Example:
+
+    pygrep.py -i 'searching' target1.txt target2.txt
+
+OPTIONS:
+
+    -E : PATTERN is an extended regexp
+    -i : case-insensitive search for PATTERN
+    -n : print line numbers
+    -r : search recursively in files in the given path
+
+    --help: print this help message
+    """
+    print(usage)
+
+def check_args(args: list) -> bool:
+    """
+    The arguments passed to pygrep.py
+    """
+    if len(args) < 2 or args[0] == '--help':
+        return False
+    return True
+
+def check_pattern(pattern: str) -> bool:
+    """
+    Compile pattern and return false if invalid
+    """
+    try:
+        re.compile(pattern)
+        return True
+    except:
+        return False
+
+def parse_args(args: list) -> dict:
+    """
+    Parse cli arguments and return the tree as a dict
+    """
+    # TODO move to class
+    OPTS = [
+        'i', # Case-insensitive search
+        'E', # Pattern is a full regexp
+        'r', # Search recursively in dir
+        'n', # Print line numbers
+    ]
+    # TODO Handle extended options? (e.g. --ignore-case)
+    LONG_OPTS = [
+        '--ignore-case',
+        '--regexp',
+        '--recursive',
+        '--line-numbers',
+    ]
+
+    args_tree = dict()
+    
+    options = []
+    # Get options
+    for arg in args:
+        # Parse short options
+        if arg[0] == '-':
+            if arg[1:] not in OPTS:
+                raise exceptions.InvalidOption(arg[1:])
+
+            options.append(arg[1:])
+
+    args_tree["options"] = options
+
+    # Filter options from args
+    remaining_args = [a for a in args if a.lstrip('-') not in options]
+
+    pattern = remaining_args[0]
+    
+    if pattern[0] == "'" and pattern[-1] == "'":
+        pattern = pattern.strip("'")
+    elif pattern[0] == '"' and pattern[-1] == '"':
+        pattern = pattern.strip('"')
+
+    args_tree["pattern"] = rf"{pattern}"
+    args_tree["files"] = remaining_args[1:]
+
+    """
+    print(args_tree)
+    sys.exit(1)
+    """
+    return args_tree
+
+def match_regexp(pattern: str, line: str) -> object:
+    """
+    Search for pattern in the given line and return
+    a match object or None if no match found.
+
+    Flags??
+    """
+    return re.search(pattern, line)
+
+def process_grep(args_tree: dict) -> list:
+    lines = []
+    found_lines = []
+    options = args_tree["options"]
+    pattern = args_tree["pattern"]
+    files = args_tree["files"]
+
+    try:
+        for f in files:
+            with open(f, 'r') as fp:
+                    lines = fp.readlines()
+
+            f = f + ':' if len(files) > 1 else ''
+
+            # Check if case insensitive
+            if 'i' in options:
+                pattern = pattern.lower()
+            # Check if regexp flag
+            if 'E' in options:
+                if not check_pattern(pattern):
+                    raise exceptions.InvalidPattern(pattern)
+                # Match regexp
+                # This isn't DRY... decorator?
+                for l in lines:
+                    matches = re.findall(pattern, l)
+                    if len(matches) > 0:
+                        l = l.strip()
+                        found_lines.append(f + l)
+            else:
+                for l in lines:
+                    if l.find(pattern) != -1:
+                        l = l.strip()
+                        found_lines.append(f + l)
+
+    except FileNotFoundError as e:
+        print(e)
+        sys.exit(1)
+
+    return found_lines
+
+# The main program...
+def __main__():
+    args = sys.argv[1:]
+
+    if not check_args(args):
+        print_usage()
+        sys.exit(1)
+
+    try:
+        args_tree = parse_args(args)
+    except exceptions.InvalidOption as e:
+        print(e.get_message())
+        print_usage()
+        sys.exit(1)
+
+    try:
+        for l in process_grep(args_tree):
+            print(l)
+    except exceptions.InvalidPattern as e:
+        print(e.get_message())
+        sys.exit(1)
+
+__main__()
diff --git a/crapgrep/exceptions.py b/crapgrep/exceptions.py
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+++ b/crapgrep/exceptions.py
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+class InvalidOption(Exception):
+    def __init__(self, invalid_opt):
+        self.invalid_opt = invalid_opt
+    def get_message(self):
+        return f"pygrep: invalid option -- '{self.invalid_opt}'"
+    
+class InvalidPattern(Exception):
+    def __init__(self, pattern):
+        self.invalid = pattern
+    def get_message(self):
+        return f"pygrep: invalid pattern -- '{self.invalid}'"
+