Fix parsing pair marks with line breaks inside

amanuensis/parser/parsing.py

@@ -47,32 +47,40 @@ def parse_paragraph(text: str) -> SpanContainer:
 
 def parse_paired_formatting(
     text: str,
-    can_cite: bool = True,
-    can_bold: bool = True,
-    can_italic: bool = True,
+    in_cite: bool = False,
+    in_bold: bool = False,
+    in_italic: bool = False,
 ) -> Spans:
     """
     Parses citations, bolds, and italics, which can be nested inside each other.
+    A single type cannot nest inside itself, which is controlled by setting the
+    flag parameters to False.
     """
     # Find positions of any paired formatting
-    first_cite = find_pair(text, "[[", "]]") if can_cite else -1
-    first_bold = find_pair(text, "**", "**") if can_bold else -1
-    first_italic = find_pair(text, "//", "//") if can_italic else -1
-    # Load the possible parse handlers into the map
+    next_cite = find_pair(text, "[[", "]]") if not in_cite else -1
+    next_bold = find_pair(text, "**", "**") if not in_bold else -1
+    next_italic = find_pair(text, "//", "//") if not in_italic else -1
+    # Create a map from a formatting mark's distance to its parse handler
     handlers = {}
-    handlers[first_cite] = lambda: parse_citation(
-        text, can_bold=can_bold, can_italic=can_italic
+    handlers[next_cite] = lambda: parse_citation(
+        text, in_bold=in_bold, in_italic=in_italic
     )
-    handlers[first_bold] = lambda: parse_bold(
-        text, can_cite=can_cite, can_italic=can_italic
+    handlers[next_bold] = lambda: parse_bold(
+        text, in_cite=in_cite, in_italic=in_italic
     )
-    handlers[first_italic] = lambda: parse_italic(
-        text, can_cite=can_cite, can_bold=can_bold
+    handlers[next_italic] = lambda: parse_italic(
+        text, in_cite=in_cite, in_bold=in_bold
     )
-    # If nothing was found, move on to the next parsing step
-    handlers[-1] = lambda: parse_breaks(text)
-    # Choose a handler based on the earliest found result
-    finds = [i for i in (first_cite, first_bold, first_italic) if i > -1]
+    # Map the next parsing step at -1. If we're currently inside a formatting
+    # mark pair, skip parsing line breaks, which are not allowed inside paired
+    # marks.
+    if in_cite or in_bold or in_italic:
+        handlers[-1] = lambda: parse_text(text)
+    else:
+        handlers[-1] = lambda: parse_breaks(text)
+    # Choose the handler for the earliest found pair, or the default handler
+    # at -1 if nothing was found.
+    finds = [i for i in (next_cite, next_bold, next_italic) if i > -1]
     first = min(finds) if finds else -1
     return handlers[first]()
 
@@ -95,8 +103,8 @@ def find_pair(text: str, open_tag: str, close_tag: str) -> int:
 
 def parse_citation(
     text: str,
-    can_bold: bool = True,
-    can_italic: bool = True,
+    in_bold: bool = False,
+    in_italic: bool = False,
 ) -> Spans:
     """
     Parses text into a citation span.
@@ -118,7 +126,7 @@ def parse_citation(
         inner_split = text_inner.split("|", 1)
         text_inner_actual, cite_target = inner_split[0], inner_split[-1]
         spans_inner = parse_paired_formatting(
-            text_inner_actual, can_cite=False, can_bold=can_bold, can_italic=can_italic
+            text_inner_actual, in_cite=True, in_bold=in_bold, in_italic=in_italic
         )
         citation = CitationSpan(spans_inner, cite_target)
         return [*spans_before, citation, *spans_after]
@@ -128,8 +136,8 @@ def parse_citation(
 
 def parse_bold(
     text: str,
-    can_cite: bool = True,
-    can_italic: bool = True,
+    in_cite: bool = False,
+    in_italic: bool = False,
 ) -> Spans:
     """
     Parses text into a bold span.
@@ -144,7 +152,7 @@ def parse_bold(
         # Parse inner text minus bold parsing
         text_inner = text[bold_open + 2 : bold_close]
         spans_inner = parse_paired_formatting(
-            text_inner, can_cite=can_cite, can_bold=False, can_italic=can_italic
+            text_inner, in_cite=in_cite, in_bold=True, in_italic=in_italic
         )
         bold = BoldSpan(spans_inner)
         return [*spans_before, bold, *spans_after]
@@ -154,8 +162,8 @@ def parse_bold(
 
 def parse_italic(
     text: str,
-    can_cite: bool = True,
-    can_bold: bool = True,
+    in_cite: bool = False,
+    in_bold: bool = False,
 ) -> Spans:
     """
     Parses text into an italic span.
@@ -170,7 +178,7 @@ def parse_italic(
         # Parse inner text minus italic parsing
         text_inner = text[italic_open + 2 : italic_close]
         spans_inner = parse_paired_formatting(
-            text_inner, can_cite=can_cite, can_bold=can_bold, can_italic=False
+            text_inner, in_cite=in_cite, in_bold=in_bold, in_italic=True
         )
         italic = ItalicSpan(spans_inner)
         return [*spans_before, italic, *spans_after]
@@ -193,3 +201,12 @@ def parse_breaks(text: str) -> Spans:
         for i in range(0, 2 * len(splits) - 1)
     ]
     return spans
+
+
+def parse_text(text: str) -> Spans:
+    """
+    Parses text with no remaining parseable marks.
+    """
+    if not text:
+        return []
+    return [TextSpan(text)]

tests/test_parser.py

@@ -153,6 +153,32 @@ def test_simple_single_parse_pairs():
     assert_text(spans, ["In the ", ["beginning"], " was ", ["the"], " Word"])
 
 
+def test_simple_parse_pairs_with_break():
+    """Test pair marks with breaks"""
+    text: str
+    spans: Spans
+
+    text = r"**glory\\" + "\nhammer**"
+    spans = parse_paired_formatting(text)
+    assert_types(spans, [[BoldSpan, TextSpan]])
+    assert_text(spans, [["glory\\\\\nhammer"]])
+
+    text = r"//glory\\" + "\nhammer//"
+    spans = parse_paired_formatting(text)
+    assert_types(spans, [[ItalicSpan, TextSpan]])
+    assert_text(spans, [["glory\\\\\nhammer"]])
+
+    text = r"**glory\\" + "\n**hammer**"
+    spans = parse_paired_formatting(text)
+    assert_types(spans, [[BoldSpan, TextSpan], TextSpan])
+    assert_text(spans, [["glory\\\\\n"], "hammer**"])
+
+    text = r"//glory\\" + "\n//hammer//"
+    spans = parse_paired_formatting(text)
+    assert_types(spans, [[ItalicSpan, TextSpan], TextSpan])
+    assert_text(spans, [["glory\\\\\n"], "hammer//"])
+
+
 def test_simple_nested_parse_pairs():
     """Test parsing for nesting bold and italic"""
     text: str