This Engineering Notebook post is a status report about the Ahas discussed here <https://groups.google.com/g/leo-editor/c/A3ocbXiwSuw/m/0EwP6t1VAgAJ>.
*Executive summary* PR #3330 <https://github.com/leo-editor/leo-editor/pull/3330> contains a c++ importer superior in all dimensions to any existing importer. Almost all of Leo's importers will use the new design pattern. PR #3330 remains a draft because I have just realized I can channel one of Vitalije's ideas to allow multi-line regex (*string*) searches in a *line-oriented* context. *Brags* The new code is: - *reliable*: The c++ importer flawlessly handles codon's c++ files. - *general*: The base Importer class contains all the new methods. Subclasses need only override the *find_blocks* method! - *stateless*: The recursive new_gen_block method generates subtrees naturally. - *simple*: All previous infrastructure disappears! All methods are short and easily understandable. *Multi-line regex searches* I was about the declare that the c++ importer was perfect. However, *C_Importer.find_blocks* is a bit clumsy. I went to bed last night wondering whether I could improve it. find_blocks applies regexs *line-by-line.* Instead, we want (say) to use Pattern.match <https://docs.python.org/3/library/re.html#re.Pattern.match> on *multi-line* strings. Aha! One of Vitalije's techniques provides the answer. Let guide_string = ''.join(self.guide_lines) Now compute the *self.index_list*, a list of tuples (starting_index, ending_index) for each of the *guide string's* lines. The lengths of self.lines, self.guide_lines, and self.index_lists are the same! find_blocks takes two arguments (i1: int, i2: int). Let: start_i = self.index_list[i1][0] end_i = self.index_list[i2][1] It's not necessary to compute self.guide_string [start_i : end_i]! Instead, find_blocks will call pat.match(self.guide_string, i, end_i), where the starting value of i is start_i. *Summary* The new importers are perfect! They are a milestone in Leo's history. Each importer needs only override i.find_blocks. Nothing could be simpler. I'll soon improve C_Importer.find_blocks as described above. I thank Vitalije for showing me how. Edward -- You received this message because you are subscribed to the Google Groups "leo-editor" group. To unsubscribe from this group and stop receiving emails from it, send an email to leo-editor+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/leo-editor/f7e6b859-fc62-4d26-a24f-aae9514121ben%40googlegroups.com.
