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1 | import re | |
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2 | from typing import List, Tuple | |
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3 | from IPython.utils import tokenize2 | |
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4 | from IPython.utils.tokenutil import generate_tokens | |
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5 | ||
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6 | def leading_indent(lines): | |
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7 | """Remove leading indentation. | |
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8 | ||
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9 | If the first line starts with a spaces or tabs, the same whitespace will be | |
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10 | removed from each following line. | |
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11 | """ | |
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12 | m = re.match(r'^[ \t]+', lines[0]) | |
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13 | if not m: | |
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14 | return lines | |
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15 | space = m.group(0) | |
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16 | n = len(space) | |
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17 | return [l[n:] if l.startswith(space) else l | |
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18 | for l in lines] | |
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19 | ||
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20 | class PromptStripper: | |
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21 | """Remove matching input prompts from a block of input. | |
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22 | ||
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23 | Parameters | |
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24 | ---------- | |
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25 | prompt_re : regular expression | |
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26 | A regular expression matching any input prompt (including continuation) | |
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27 | initial_re : regular expression, optional | |
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28 | A regular expression matching only the initial prompt, but not continuation. | |
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29 | If no initial expression is given, prompt_re will be used everywhere. | |
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30 | Used mainly for plain Python prompts, where the continuation prompt | |
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31 | ``...`` is a valid Python expression in Python 3, so shouldn't be stripped. | |
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32 | ||
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33 | If initial_re and prompt_re differ, | |
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34 | only initial_re will be tested against the first line. | |
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35 | If any prompt is found on the first two lines, | |
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36 | prompts will be stripped from the rest of the block. | |
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37 | """ | |
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38 | def __init__(self, prompt_re, initial_re=None): | |
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39 | self.prompt_re = prompt_re | |
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40 | self.initial_re = initial_re or prompt_re | |
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41 | ||
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42 | def _strip(self, lines): | |
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43 | return [self.prompt_re.sub('', l, count=1) for l in lines] | |
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44 | ||
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45 | def __call__(self, lines): | |
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46 | if self.initial_re.match(lines[0]) or \ | |
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47 | (len(lines) > 1 and self.prompt_re.match(lines[1])): | |
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48 | return self._strip(lines) | |
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49 | return lines | |
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50 | ||
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51 | classic_prompt = PromptStripper( | |
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52 | prompt_re=re.compile(r'^(>>>|\.\.\.)( |$)'), | |
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53 | initial_re=re.compile(r'^>>>( |$)') | |
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54 | ) | |
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55 | ||
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56 | ipython_prompt = PromptStripper(re.compile(r'^(In \[\d+\]: |\s*\.{3,}: ?)')) | |
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57 | ||
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58 | def cell_magic(lines): | |
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59 | if not lines[0].startswith('%%'): | |
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60 | return lines | |
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61 | if re.match('%%\w+\?', lines[0]): | |
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62 | # This case will be handled by help_end | |
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63 | return lines | |
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64 | magic_name, first_line = lines[0][2:].partition(' ') | |
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65 | body = '\n'.join(lines[1:]) | |
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66 | return ['get_ipython().run_cell_magic(%r, %r, %r)' % (magic_name, first_line, body)] | |
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67 | ||
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68 | line_transforms = [ | |
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69 | leading_indent, | |
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70 | classic_prompt, | |
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71 | ipython_prompt, | |
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72 | cell_magic, | |
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73 | ] | |
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74 | ||
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75 | # ----- | |
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76 | ||
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77 | def help_end(tokens_by_line): | |
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78 | pass | |
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79 | ||
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80 | def escaped_command(tokens_by_line): | |
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81 | pass | |
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82 | ||
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83 | def _find_assign_op(token_line): | |
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84 | # Find the first assignment in the line ('=' not inside brackets) | |
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85 | # We don't try to support multiple special assignment (a = b = %foo) | |
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86 | paren_level = 0 | |
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87 | for i, ti in enumerate(token_line): | |
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88 | s = ti.string | |
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89 | if s == '=' and paren_level == 0: | |
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90 | return i | |
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91 | if s in '([{': | |
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92 | paren_level += 1 | |
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93 | elif s in ')]}': | |
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94 | paren_level -= 1 | |
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95 | ||
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96 | class MagicAssign: | |
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97 | @staticmethod | |
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98 | def find(tokens_by_line): | |
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99 | """Find the first magic assignment (a = %foo) in the cell. | |
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100 | ||
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101 | Returns (line, column) of the % if found, or None. | |
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102 | """ | |
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103 | for line in tokens_by_line: | |
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104 | assign_ix = _find_assign_op(line) | |
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105 | if (assign_ix is not None) \ | |
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106 | and (len(line) >= assign_ix + 2) \ | |
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107 | and (line[assign_ix+1].string == '%') \ | |
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108 | and (line[assign_ix+2].type == tokenize2.NAME): | |
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109 | return line[assign_ix+1].start | |
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110 | ||
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111 | @staticmethod | |
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112 | def transform(lines: List[str], start: Tuple[int, int]): | |
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113 | """Transform a magic assignment found by find | |
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114 | """ | |
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115 | start_line = start[0] - 1 # Shift from 1-index to 0-index | |
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116 | start_col = start[1] | |
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117 | ||
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118 | print("Start at", start_line, start_col) | |
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119 | print("Line", lines[start_line]) | |
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120 | ||
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121 | lhs, rhs = lines[start_line][:start_col], lines[start_line][start_col:-1] | |
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122 | assert rhs.startswith('%'), rhs | |
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123 | magic_name, _, args = rhs[1:].partition(' ') | |
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124 | args_parts = [args] | |
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125 | end_line = start_line | |
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126 | # Follow explicit (backslash) line continuations | |
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127 | while end_line < len(lines) and args_parts[-1].endswith('\\'): | |
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128 | end_line += 1 | |
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129 | args_parts[-1] = args_parts[-1][:-1] # Trim backslash | |
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130 | args_parts.append(lines[end_line][:-1]) # Trim newline | |
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131 | args = ' '.join(args_parts) | |
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132 | ||
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133 | lines_before = lines[:start_line] | |
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134 | call = "get_ipython().run_line_magic({!r}, {!r})".format(magic_name, args) | |
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135 | new_line = lhs + call + '\n' | |
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136 | lines_after = lines[end_line+1:] | |
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137 | ||
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138 | return lines_before + [new_line] + lines_after | |
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139 | ||
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140 | def make_tokens_by_line(lines): | |
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141 | tokens_by_line = [[]] | |
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142 | for token in generate_tokens(iter(lines).__next__): | |
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143 | tokens_by_line[-1].append(token) | |
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144 | if token.type == tokenize2.NEWLINE: | |
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145 | tokens_by_line.append([]) | |
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146 | ||
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147 | return tokens_by_line | |
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148 | ||
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149 | class TokenTransformers: | |
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150 | def __init__(self): | |
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151 | self.transformers = [ | |
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152 | MagicAssign | |
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153 | ] | |
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154 | ||
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155 | def do_one_transform(self, lines): | |
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156 | """Find and run the transform earliest in the code. | |
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157 | ||
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158 | Returns (changed, lines). | |
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159 | ||
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160 | This method is called repeatedly until changed is False, indicating | |
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161 | that all available transformations are complete. | |
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162 | ||
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163 | The tokens following IPython special syntax might not be valid, so | |
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164 | the transformed code is retokenised every time to identify the next | |
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165 | piece of special syntax. Hopefully long code cells are mostly valid | |
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166 | Python, not using lots of IPython special syntax, so this shouldn't be | |
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167 | a performance issue. | |
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168 | """ | |
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169 | tokens_by_line = make_tokens_by_line(lines) | |
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170 | candidates = [] | |
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171 | for transformer in self.transformers: | |
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172 | locn = transformer.find(tokens_by_line) | |
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173 | if locn: | |
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174 | candidates.append((locn, transformer)) | |
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175 | ||
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176 | if not candidates: | |
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177 | # Nothing to transform | |
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178 | return False, lines | |
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179 | ||
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180 | first_locn, transformer = min(candidates) | |
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181 | return True, transformer.transform(lines, first_locn) | |
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182 | ||
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183 | def __call__(self, lines): | |
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184 | while True: | |
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185 | changed, lines = self.do_one_transform(lines) | |
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186 | if not changed: | |
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187 | return lines | |
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188 | ||
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189 | def assign_from_system(tokens_by_line, lines): | |
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190 | pass | |
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191 | ||
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192 | ||
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193 | def transform_cell(cell): | |
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194 | if not cell.endswith('\n'): | |
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195 | cell += '\n' # Ensure every line has a newline | |
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196 | lines = cell.splitlines(keepends=True) | |
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197 | for transform in line_transforms: | |
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198 | #print(transform, lines) | |
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199 | lines = transform(lines) | |
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200 | ||
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201 | lines = TokenTransformers()(lines) | |
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202 | for line in lines: | |
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203 | print('~~', line) |
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