Merge pull request #39 from cmacmackin/lines-and-line-ranges

Add support for specifying lines and line ranges

README.md

@@ -47,6 +47,30 @@ Markdown is being called. If you would like to change the directory relative to
 which paths are evaluated, then this can be done by specifying the extension
 setting ``base_path``.
 
+### Line Ranges
+
+You can also define specific lines or line ranges to include by specifying `lines`:
+
+```Markdown
+{!filename!lines=1  3 8-10  2}
+```
+
+`lines` takes a sequence of integers separated by spaces (one or more), or it can also
+take line ranges specified with a start line and an end line separated by a dash (`-`).
+
+In the example above, it would read the file called `filename` and include the lines
+`1`, `3`, `8`, `9`, `10`, `2`.
+
+Notice that line `9` was not explicitly set. But it was still included as part of the
+range `8-10`.
+
+Also, notice that line `2` is set *after* the range `8-10`. This means that the
+line `2` in `filename` will be included *after* (below) the range `8-10`.
+
+You can use this to include lines in a different order than the original file. But it
+also means that if you want to preserve the original order, you have to pay attention
+to the order in which you specify the lines.
+
 ## Configuration
 
 The following settings can be specified when initialising the plugin.

markdown_include/include.py

@@ -29,7 +29,7 @@
 from markdown.extensions import Extension
 from markdown.preprocessors import Preprocessor
 
-INC_SYNTAX = re.compile(r'\{!\s*(.+?)\s*!\}')
+INC_SYNTAX = re.compile(r'{!\s*(.+?)\s*!((\blines\b)=([0-9 -]+))?\}')
 HEADING_SYNTAX = re.compile( '^#+' )
 
 
@@ -91,7 +91,7 @@ def run(self, lines):
                         )
                     try:
                         with open(filename, 'r', encoding=self.encoding) as r:
-                            text = self.run(r.readlines())
+                            original_text = self.run(r.readlines())
 
                     except Exception as e:
                         if not self.throwException:
@@ -101,6 +101,46 @@ def run(self, lines):
                             break
                         else:
                             raise e
+                    if m.group(2) is None:
+                        text = original_text
+                    else:
+                        lines_str = m.group(4)
+                        lines_blocks = lines_str.split()
+                        wanted_lines = []
+                        for block in lines_blocks:
+                            if "-" in block:
+                                start, end = block.strip().split("-")
+                                current_start = int(start)
+                                current_end = int(end)
+                                if not len(original_text) >= current_end:
+                                    current_end = len(original_text)
+                                    print(
+                                        f"Warning: line range: {block} ending in "
+                                        f"line: {end} is larger than file: {filename} "
+                                        f"using end: {current_end}"
+                                    )
+                                if not current_start <= current_end:
+                                    current_start = max(current_end - 1, 1)
+                                    print(
+                                        f"Warning: in line range: {block} "
+                                        f"the start line: {start} is not "
+                                        f"smaller than the end line: {current_end} "
+                                        f"using start: {current_start}"
+                                    )
+
+                                wanted_lines.extend(original_text[current_start-1:current_end])
+                            else:
+                                wanted_line = int(block.strip())
+                                current_line = wanted_line
+                                if current_line > len(original_text):
+                                    current_line = len(original_text)
+                                    print(
+                                        f"Warning: line: {wanted_line} is larger than "
+                                        f"file: {filename} using end: {current_line}"
+                                    )
+                                wanted_lines.append(original_text[current_line-1])
+                        text = wanted_lines
+
 
                     if len(text) == 0:
                         text.append('')

tests/resources/longer.md

@@ -0,0 +1,8 @@
+This is line 1
+This is line 2
+This is line 3
+This is line 4
+This is line 5
+This is line 6
+This is line 7
+This is line 8

tests/test_include.py

@@ -142,3 +142,51 @@ def test_processor_lines():
     result_lines = processor.run(source)
 
     assert len(result_lines) == 9
+
+
+def test_include_lines(markdown_include):
+    source = "{!resources/longer.md!lines=1 3}"
+    html = markdown.markdown(source, extensions=[markdown_include])
+
+    assert html == dedent(
+        """\
+        <p>This is line 1
+        This is line 3</p>"""
+    )
+
+
+def test_include_line_range(markdown_include):
+    source = "{!resources/longer.md!lines=3-5}"
+    html = markdown.markdown(source, extensions=[markdown_include])
+
+    assert html == dedent(
+        """\
+        <p>This is line 3
+        This is line 4
+        This is line 5</p>"""
+    )
+
+
+def test_include_lines_and_line_range(markdown_include):
+    source = "{!resources/longer.md!lines=1 3-5 8}"
+    html = markdown.markdown(source, extensions=[markdown_include])
+
+    assert html == dedent(
+        """\
+        <p>This is line 1
+        This is line 3
+        This is line 4
+        This is line 5
+        This is line 8</p>"""
+    )
+
+
+def test_include_lines_out_of_order(markdown_include):
+    source = "{!resources/longer.md!lines=3 1}"
+    html = markdown.markdown(source, extensions=[markdown_include])
+
+    assert html == dedent(
+        """\
+        <p>This is line 3
+        This is line 1</p>"""
+    )