comparison: parse.py
parse.py
- changeset 2
- 50d3086070df
- child 3
- 1dc58f44d556
equal
deleted
inserted
replaced
| 1:5411a25cfca7 | 2:50d3086070df |
|---|---|
| 1 import linetypes | |
| 2 import re | |
| 3 from geometry import * | |
| 4 | |
| 5 class BadLdrawLine(Exception): | |
| 6 pass | |
| 7 | |
| 8 def parse_ldraw_code(line): | |
| 9 line = line.strip() | |
| 10 if not line: | |
| 11 return linetypes.EmptyLine() | |
| 12 elif line == '0': | |
| 13 return linetypes.Comment('') | |
| 14 elif line.startswith('0 '): | |
| 15 return linetypes.Comment(line[2:].strip()) | |
| 16 elif line.startswith('1 '): | |
| 17 return parse_ldraw_subfile_reference(line) | |
| 18 elif line.startswith('2 '): | |
| 19 return parse_ldraw_line(line) | |
| 20 elif line.startswith('3 '): | |
| 21 return parse_ldraw_triangle(line) | |
| 22 elif line.startswith('4 '): | |
| 23 return parse_ldraw_quadrilateral(line) | |
| 24 elif line.startswith('5 '): | |
| 25 return parse_ldraw_contour(line) | |
| 26 else: | |
| 27 raise BadLdrawLine('unknown line type') | |
| 28 | |
| 29 def parse_ldraw_subfile_reference(line): | |
| 30 pattern = r'^1\s+(\d+)' + r'\s+([^ ]+)' * (3 + 9 + 1) + r'\s*$' | |
| 31 match = re.search(pattern, line) | |
| 32 if not match: | |
| 33 raise BadLdrawLine('unable to parse') | |
| 34 groups = list(match.groups()) | |
| 35 indices = { | |
| 36 'color': 0, | |
| 37 'anchor': slice(1, 4), | |
| 38 'matrix': slice(4, 13), | |
| 39 'subfile_path': 13 | |
| 40 } | |
| 41 try: | |
| 42 color = int(groups[indices['color']]) | |
| 43 vertex_values = [float(x) for x in groups[indices['anchor']]] | |
| 44 matrix_values = [float(x) for x in groups[indices['matrix']]] | |
| 45 except ValueError: | |
| 46 raise BadLdrawLine('bad numeric values') | |
| 47 return linetypes.SubfileReference( | |
| 48 color = color, | |
| 49 anchor = Vertex(*vertex_values), | |
| 50 matrix = TransformationMatrix(matrix_values), | |
| 51 subfile_path = groups[indices['subfile_path']] | |
| 52 ) | |
| 53 | |
| 54 def generic_parse_polygon(line, *, type_code, vertex_count): | |
| 55 pattern = r'^' \ | |
| 56 + str(type_code) \ | |
| 57 + '\s+(\d+)' \ | |
| 58 + r'\s+([^ ]+)' * (vertex_count * 3) \ | |
| 59 + r'\s*$' | |
| 60 match = re.search(pattern, line) | |
| 61 if not match: | |
| 62 raise BadLdrawLine(str.format('cannot parse type-{} line', type_code)) | |
| 63 vertices = [] | |
| 64 for vertex_index in range(vertex_count): | |
| 65 slice_begin = 1 + vertex_index * 3 | |
| 66 slice_end = 1 + (vertex_index + 1) * 3 | |
| 67 coordinates = match.groups()[slice_begin:slice_end] | |
| 68 assert(len(coordinates) == 3) | |
| 69 try: | |
| 70 coordinates = [float(x) for x in coordinates] | |
| 71 except ValueError: | |
| 72 raise BadLdrawLine('bad numeric values') | |
| 73 vertices.append(Vertex(*coordinates)) | |
| 74 return { | |
| 75 'color': int(match.group(1)), | |
| 76 'vertices': vertices, | |
| 77 } | |
| 78 | |
| 79 def parse_ldraw_line(line): | |
| 80 parse_result = generic_parse_polygon(line, type_code = 2, vertex_count = 2) | |
| 81 return linetypes.LineSegment( | |
| 82 color = parse_result['color'], | |
| 83 geometry = LineSegment(*parse_result['vertices']), | |
| 84 ) | |
| 85 | |
| 86 def parse_ldraw_triangle(line): | |
| 87 parse_result = generic_parse_polygon(line, type_code = 3, vertex_count = 3) | |
| 88 return linetypes.Triangle( | |
| 89 color = parse_result['color'], | |
| 90 geometry = Polygon(parse_result['vertices']), | |
| 91 ) | |
| 92 | |
| 93 def parse_ldraw_quadrilateral(line): | |
| 94 parse_result = generic_parse_polygon(line, type_code = 4, vertex_count = 4) | |
| 95 return linetypes.Quadrilateral( | |
| 96 color = parse_result['color'], | |
| 97 geometry = Polygon(parse_result['vertices']), | |
| 98 ) | |
| 99 | |
| 100 def parse_ldraw_contour(line): | |
| 101 parse_result = generic_parse_polygon(line, type_code = 5, vertex_count = 4) | |
| 102 return linetypes.Contour( | |
| 103 color = parse_result['color'], | |
| 104 geometry = LineSegment(*parse_result['vertices'][0:2]), | |
| 105 control_points = parse_result['vertices'][2:], | |
| 106 ) |
