Add separate transforms module with paragraph()

5 files changed, 38 insertions, 4 deletions

diff --git a/mammoth/__init__.py b/mammoth/__init__.py
index fe480ec..27cc580 100644
--- a/mammoth/__init__.py
+++ b/mammoth/__init__.py
@@ -1,8 +1,8 @@
-from . import docx, conversion, options, images, underline
+from . import docx, conversion, options, images, transforms, underline
 from .raw_text import extract_raw_text_from_element
 from .docx.style_map import write_style_map, read_style_map
 
-__all__ = ["convert_to_html", "extract_raw_text", "images", "underline"]
+__all__ = ["convert_to_html", "extract_raw_text", "images", "transforms", "underline"]
 
 
 _undefined = object()
diff --git a/mammoth/documents.py b/mammoth/documents.py
index a8c3fb2..fe1cbcb 100644
--- a/mammoth/documents.py
+++ b/mammoth/documents.py
@@ -2,7 +2,8 @@ import cobble
 
 
 class Element(object):
-    pass
+    def copy(self, **kwargs):
+        return cobble.copy(self, **kwargs)
 
 
 class HasChildren(Element):
diff --git a/mammoth/transforms.py b/mammoth/transforms.py
new file mode 100644
index 0000000..6eb6d92
--- /dev/null
+++ b/mammoth/transforms.py
@@ -0,0 +1,22 @@
+from . import documents
+
+
+def paragraph(transform_paragraph):
+    def transform_element(element):
+        if isinstance(element, documents.Paragraph):
+            return transform_paragraph(element)
+        else:
+            return element
+    
+    return _each_element(transform_element)
+
+
+def _each_element(transform_element):
+    def transform_element_and_children(element):
+        if isinstance(element, documents.HasChildren):
+            children = list(map(transform_element, element.children))
+            element = element.copy(children=children)
+        
+        return transform_element(element)
+    
+    return transform_element_and_children
diff --git a/setup.py b/setup.py
index 5ce5336..a68eb9c 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@ def read(fname):
 
 
 _install_requires = [
-    "cobble>=0.1.1,<0.2",
+    "cobble>=0.1.2,<0.2",
 ]
 
 if sys.version_info[:2] <= (2, 6):
diff --git a/tests/mammoth_tests.py b/tests/mammoth_tests.py
index bcdf5a8..1dcbaa9 100644
--- a/tests/mammoth_tests.py
+++ b/tests/mammoth_tests.py
@@ -306,6 +306,17 @@ def transform_document_is_applied_to_document_before_conversion():
 
 
 @istest
+def paragraph_transform_only_transforms_paragraphs():
+    def transform_paragraph(paragraph):
+        return paragraph.copy(style_id="Heading1")
+    transform_document = mammoth.transforms.paragraph(transform_paragraph)
+    with open(test_path("single-paragraph.docx"), "rb") as fileobj:
+        result = mammoth.convert_to_html(fileobj=fileobj, transform_document=transform_document)
+        assert_equal("<h1>Walking on imported air</h1>", result.value)
+        assert_equal([], result.messages)
+
+
+@istest
 def docx_containing_one_paragraph_can_be_converted_to_markdown():
     with open(test_path("single-paragraph.docx"), "rb") as fileobj:
         result = mammoth.convert_to_markdown(fileobj=fileobj)