todo.py

# MIT License

# Copyright 2025 @asyncze (Michael Sjöberg)

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# Tokenizer for Todo

DEFAULT = "default"
KEYWORD = "keyword"
COMMENT = "comment"
NAME = "name"
SPECIAL = "special"
ERROR = "error"
SUCCESS = "success"

class Lexer(object):
    def __init__(self): pass

    def comment_char(self): return None

    def lexer_name(self): return "Todo"
    
    def tokenize(self, text):
        tokens = []
        current_char = ''
        current_char_index = 0

        while current_char_index < len(text):
            current_char = text[current_char_index]
            match current_char:
                
                # whitespace
                case ' ' | '\t' | '\r' | '\n':
                    current_char_index += 1

                # header
                case '#':                    
                    start_pos = current_char_index                    
                    current_char_index += 1
                    line = current_char
                    
                    while current_char_index < len(text) and text[current_char_index] != '\n':
                        line += text[current_char_index]
                        current_char_index += 1
                    
                    tokens.append((KEYWORD, int(start_pos), str(line)))
                
                # done
                case '+':                    
                    start_pos = current_char_index                    
                    current_char_index += 1
                    line = current_char
                    
                    while current_char_index < len(text) and text[current_char_index] != '\n':
                        line += text[current_char_index]
                        current_char_index += 1
                    
                    tokens.append((SUCCESS, int(start_pos), str(line)))

                # not done
                case '-':                    
                    start_pos = current_char_index
                    current_char_index += 1
                    line = current_char
                    
                    while current_char_index < len(text) and text[current_char_index] != '\n':

                        # handle nested special
                        if text[current_char_index] == '[':
                            tokens.append((NAME, int(start_pos), str(line))) # append token for line up until [

                            # todo : create helper function for this
                            start_pos = current_char_index # set start_pos for special
                            special = text[current_char_index]
                            current_char_index += 1
                            
                            while current_char_index < len(text) and text[current_char_index] != '\n':
                                special += text[current_char_index]

                                if text[current_char_index] == ']':
                                    current_char_index += 1
                                    break
                                else:
                                    current_char_index += 1
                            
                            tokens.append((SPECIAL, int(start_pos), str(special)))

                            # handle special case of whitespace at start of next name section on line
                            if current_char_index < len(text) and text[current_char_index] == ' ': current_char_index += 1

                            start_pos = current_char_index # reset start pos for next char on line
                            line = str() # reset line to char at new start pos
                        else:
                            line += text[current_char_index]
                            current_char_index += 1
                    
                    tokens.append((NAME, int(start_pos), str(line)))

                # important
                case '*':                    
                    start_pos = current_char_index                    
                    current_char_index += 1
                    line = current_char
                    
                    while current_char_index < len(text) and text[current_char_index] != '\n':
                        line += text[current_char_index]
                        current_char_index += 1
                    
                    tokens.append((ERROR, int(start_pos), str(line)))
                
                # comment
                case _:
                    tokens.append((COMMENT, int(current_char_index), str(current_char)))
                    current_char_index += 1

        return tokens