WIP: Experimental error handling with snippets of input for OutputGenerator. Would be nice to generalise for TransformProcessor, which is not easy as they don't have a common parent class.

src/formatitko/html_generator.py

@@ -29,10 +29,10 @@ class HTMLGenerator(OutputGenerator):
 		self.imageProcessor = imageProcessor
 		super().__init__(output_file, *args, **kwargs)
 
-	def generate(self, e: Union[Element, ListContainer]):
+	def _generate(self, e: Union[Element, ListContainer]):
 		if hasattr(e, "attributes") and "only" in e.attributes and e.attributes["only"] != "html":
 			return
-		super().generate(e)
+		super()._generate(e)
 
 	def escape_special_chars(self, text: str) -> str:
 		text = text.replace("&", "&")
@@ -190,7 +190,7 @@ class HTMLGenerator(OutputGenerator):
 			attributes["alt"] = e.title
 		else:
 			fake_out = io.StringIO()
-			HTMLGenerator(fake_out, self.katexClient, self.imageProcessor).generate(e.content)
+			HTMLGenerator(fake_out, self.katexClient, self.imageProcessor)._generate(e.content)
 			attributes["alt"] = fake_out.getvalue()
 		
 		if len(srcset) != 0:
@@ -202,7 +202,7 @@ class HTMLGenerator(OutputGenerator):
 		img = RawInline(self.single_tag("img", attributes))
 		link = Link(img, url=url)
 
-		self.generate(link)
+		self._generate(link)
 
 	def generate_InlineGroup(self, e: InlineGroup):
 		self.generate_Group(e)
@@ -216,10 +216,10 @@ class HTMLGenerator(OutputGenerator):
 		self.katexClient.endgroup()
 
 	def generate_Plain(self, e: Plain):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_LineItem(self, e: LineItem):
-		self.generate(e.content)
+		self._generate(e.content)
 		self.write("<br>")
 		self.endln()
 	
@@ -229,12 +229,12 @@ class HTMLGenerator(OutputGenerator):
 		tag = self.tagname(e)
 		if inline is not None:
 			self.write(self.start_tag(tag)+" (")
-			self.generate(inline)
+			self._generate(inline)
 			self.write(") "+self.end_tag(tag))
 		else:
 			self.writeln(self.start_tag(tag) + "(")
 			self.indent_more()
-			self.generate(e.content)
+			self._generate(e.content)
 			self.indent_less()
 			self.writeln(self.end_tag(tag) + ")")
 

src/formatitko/katex.py

@@ -79,7 +79,7 @@ class KatexClient:
 		if "error" in response:
 			raise KatexServerError(response["error"])
 		if "error" in response["results"][0]:
-			raise KatexError(response["results"][0]["error"])
+			raise KatexError(response["results"][0]["error"] + " in $" + tex + "$")
 		else:
 			return response["results"][0]["html"]
 

src/formatitko/latex_generator.py

@@ -17,10 +17,10 @@ class LaTeXGenerator(OutputGenerator):
 		self.imageProcessor = imageProcessor
 		super().__init__(output_file, *args, **kwargs)
 
-	def generate(self, e: Union[Element, ListContainer]):
+	def _generate(self, e: Union[Element, ListContainer]):
 		if hasattr(e, "attributes") and "only" in e.attributes and e.attributes["only"] != "tex":
 			return
-		super().generate(e)
+		super()._generate(e)
 
 	def escape_special_chars(self, text: str) -> str:
 		text = text.replace("&", "\\&")
@@ -58,14 +58,14 @@ class LaTeXGenerator(OutputGenerator):
 		self.endln()
 
 	def generate_Para(self, e: Para):
-		self.generate(e.content)
+		self._generate(e.content)
 		self.writeln("") # This ensures an empty line
 
 	def generate_Plain(self, e: Plain):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_Span(self, e: Plain):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_Header(self, e: Header):
 		tag = {

src/formatitko/output_generator.py

@@ -3,18 +3,31 @@ from panflute import Cite, Code, Emph, Image, LineBreak, Link, Math, Note, Quote
 from panflute import BlockQuote, BulletList, Citation, CodeBlock, Definition, DefinitionItem, DefinitionList, Div, Figure, Header, HorizontalRule, LineBlock, LineItem, ListItem, MetaBlocks, MetaBool, MetaInlines, MetaList, MetaMap, MetaString, Null, OrderedList, Para, Plain, RawBlock, Table, TableBody, TableFoot, TableHead
 from panflute import TableRow, TableCell, Caption, Doc
 from panflute import MetaValue
+from panflute import stringify
 from typing import Union, Callable
 
 from .whitespace import NBSP
 from .elements import FQuoted
 from .context import Group, InlineGroup, BlockGroup, Context
 
-import re
+import re, sys
 
 class UnknownElementError(Exception):
 	"An unknown Element has been passed to the OutputGenerator, probably because panflute introduced a new one."
 	pass
 
+
+class OutputGeneratorError(Exception):
+	"A generic exception which wraps other exceptions and adds element-based traceback"
+	elements: list[Union[Element, ListContainer, list[Union[Element, ListContainer]]]]
+
+	def __init__(self, e: Union[Element, ListContainer, list[Union[Element, ListContainer]]], *args):
+		self.elements = [e]
+		super().__init__(args)
+
+	def add_element(self, e: Union[Element, ListContainer, list[Union[Element, ListContainer]]]):
+		self.elements.append(e)
+
 class OutputGenerator:
 	_empty_lines: int
 	context: Union[Context, None]
@@ -101,28 +114,53 @@ class OutputGenerator:
 		}
 
 	def generate(self, e: Union[Element, ListContainer, list[Union[Element, ListContainer]]]):
-		if isinstance(e, Group):
+		try:
-			old_context = self.context
+			self._generate(e)
-			self.context = e.context
+		except OutputGeneratorError as err:
-		if isinstance(e, list):
+			def eprint(*args, **kwargs):
-			self.generate_list(e)
+				print(*args, file=sys.stderr, **kwargs)
-		elif isinstance(e, ListContainer):
+			eprint("Error occured in ", end="")
-			self.generate_ListContainer(e)
+			for i in range(len(err.elements)-1, 0, -1):
-		elif isinstance(e, Inline):
+				if hasattr(err.elements[i], "content") and isinstance(err.elements[i].content[0], Inline):
-			self.generate_Inline(e)
+					eprint()
-		elif isinstance(e, Block):
+					eprint('on line: "' + stringify(err.elements[i]) + '"', end="")
-			self.generate_Block(e)
+					break
-		elif isinstance(e, MetaValue):
+				eprint(type(err.elements[i]).__name__ + "[" + str(err.elements[i-1].index) + "]", end=": ")
-			self.generate_MetaValue(e)
+			eprint()
-		elif isinstance(e, MetaList):
+			eprint("in element: " + str(err.elements[0]))
-			self.generate_MetaList(e)
+			sys.tracebacklimit = 0
-		else:
+			raise err.__cause__ from None
-			try:
+
-				self.TYPE_DICT_MISC[type(e)](e)
+	def _generate(self, e: Union[Element, ListContainer, list[Union[Element, ListContainer]]]):
-			except KeyError:
+		try:
-				raise UnknownElementError(type(e))
+			if isinstance(e, Group):
-		if isinstance(e, Group):
+				old_context = self.context
-			self.context = old_context
+				self.context = e.context
+			if isinstance(e, list):
+				self.generate_list(e)
+			elif isinstance(e, ListContainer):
+				self.generate_ListContainer(e)
+			elif isinstance(e, Inline):
+				self.generate_Inline(e)
+			elif isinstance(e, Block):
+				self.generate_Block(e)
+			elif isinstance(e, MetaValue):
+				self.generate_MetaValue(e)
+			elif isinstance(e, MetaList):
+				self.generate_MetaList(e)
+			else:
+				try:
+					self.TYPE_DICT_MISC[type(e)](e)
+				except KeyError as err:
+					raise UnknownElementError(type(e)) from err
+			if isinstance(e, Group):
+				self.context = old_context
+		except OutputGeneratorError as err:
+			if not isinstance(e, ListContainer):
+				err.add_element(e)
+			raise err
+		except Exception as err:
+			raise OutputGeneratorError(e) from err
 
 	def escape_special_chars(self, text: str) -> str:
 		return text
@@ -210,13 +248,13 @@ class OutputGenerator:
 
 	def generate_simple_inline_tag(self, tag: str, content: Union[ListContainer, Element, list[Union[Element, ListContainer]]], attributes: dict[str,str]={}):
 		self.write(self.start_tag(tag, attributes))
-		self.generate(content)
+		self._generate(content)
 		self.write(self.end_tag(tag))
 
 	def generate_simple_block_tag(self, tag: str, content: Union[ListContainer, Element, list[Union[Element, ListContainer]]], attributes: dict[str,str]={}):
 		self.writeln(self.start_tag(tag, attributes))
 		self.indent_more()
-		self.generate(content)
+		self._generate(content)
 		self.indent_less()
 		self.writeln(self.end_tag(tag))
 
@@ -235,27 +273,27 @@ class OutputGenerator:
 
 	def generate_ListContainer(self, e: ListContainer):
 		for child in e:
-			self.generate(child)
+			self._generate(child)
 
 	def generate_list(self, e: list):
 		for el in e:
-			self.generate(el)
+			self._generate(el)
 
 	def generate_MetaList(self, e: MetaList):
 		for child in e:
-			self.generate(child)
+			self._generate(child)
 
 	def generate_MetaValue(self, e: MetaValue):
 		try:
 			self.TYPE_DICT_META[type(e)](e)
 		except KeyError:
-			self.generate(e.content)
+			self._generate(e.content)
 
 	def generate_MetaBlocks(self, e: MetaBlocks):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_MetaInlines(self, e: MetaInlines):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_MetaBool(self, e: MetaBool):
 		self.generate_simple_tag(e)
@@ -285,33 +323,33 @@ class OutputGenerator:
 		if e.style == "cs":
 			if e.quote_type == "SingleQuote":
 				self.write("‚")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("‘")
 			elif e.quote_type == "DoubleQuote":
 				self.write("„")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("“")
 		elif e.style == "en":
 			if e.quote_type == "SingleQuote":
 				self.write("‘")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("’")
 			elif e.quote_type == "DoubleQuote":
 				self.write("“")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("”")
 		else:
 			if e.quote_type == "SingleQuote":
 				self.write("'")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("'")
 			elif e.quote_type == "DoubleQuote":
 				self.write("\"")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("\"")
 			else:
 				self.write("\"")
-				self.generate(e.content)
+				self._generate(e.content)
 				self.write("\"")
 
 
@@ -434,10 +472,10 @@ class OutputGenerator:
 
 	def generate_Doc(self, e: Doc):
 		if "header_content" in e.metadata:
-			self.generate(e.metadata["header_content"])
+			self._generate(e.metadata["header_content"])
 		self.generate_simple_tag(e)
 		if "footer_content" in e.metadata:
-			self.generate(e.metadata["footer_content"])
+			self._generate(e.metadata["footer_content"])
 	
 	def generate_BlockGroup(self, e: BlockGroup):
 		self.generate_simple_tag(e)

src/formatitko/tex_generator.py

@@ -41,10 +41,10 @@ class UCWTexGenerator(OutputGenerator):
 		text = text.replace("​", "")
 		return text
 
-	def generate(self, e: Union[Element, ListContainer]):
+	def _generate(self, e: Union[Element, ListContainer]):
 		if hasattr(e, "attributes") and "only" in e.attributes and e.attributes["only"] != "tex":
 			return
-		super().generate(e)
+		super()._generate(e)
 
 	def writepar(self, text: str):
 		self.ensure_empty(2)
@@ -60,7 +60,7 @@ class UCWTexGenerator(OutputGenerator):
 
 	def generate_Para(self, e: Para):
 		self.ensure_empty(2)
-		self.generate(e.content)
+		self._generate(e.content)
 		self.ensure_empty(2)
 
 	def generate_HorizontalRule(self, e: HorizontalRule):
@@ -72,7 +72,7 @@ class UCWTexGenerator(OutputGenerator):
 		self.writeln(r"\ucwmodule{verb}")
 		self.writeln(r"\ucwmodule{link}")
 		self.writeln(r"\input formatitko.tex")
-		self.generate(e.content)
+		self._generate(e.content)
 		self.writeln(r"\bye")
 
 	def get_language_macro(self, lang: str):
@@ -88,21 +88,21 @@ class UCWTexGenerator(OutputGenerator):
 	def generate_InlineGroup(self, e: InlineGroup):
 		self.write(r"{")
 		self.write(self.get_language_macro(self.context.get_metadata("lang")))
-		self.generate(e.content)
+		self._generate(e.content)
 		self.write(r"}")
 
 	def generate_BlockGroup(self, e: BlockGroup):
 		self.writeln(r"\begingroup")
 		self.indent_more()
 		self.writeln(self.get_language_macro(self.context.get_metadata("lang")))
-		self.generate(e.content)
+		self._generate(e.content)
 		self.indent_less()
 		self.writeln(r"\endgroup")
 	
 	def generate_Header(self, e: Header):
 		self.ensure_empty(2)
 		self.write("\\"+"sub"*(e.level-1)+"section{")
-		self.generate(e.content)
+		self._generate(e.content)
 		self.write(r"}")
 		self.ensure_empty(2)
 
@@ -156,12 +156,12 @@ class UCWTexGenerator(OutputGenerator):
 		self.writeln(r"\vskip5pt")
 		self.writeln(r"\centerline{")
 		self.indent_more()
-		self.generate(e.content)
+		self._generate(e.content)
 		self.indent_less()
 		self.writeln(r"}")
 		self.writeln(r"\centerline{")
 		self.indent_more()
-		self.generate(e.caption)
+		self._generate(e.caption)
 		self.indent_less()
 		self.writeln(r"}")
 		self.writeln(r"\vskip5pt{}")
@@ -173,7 +173,7 @@ class UCWTexGenerator(OutputGenerator):
 		else:
 			self.write(r"{\I{}")
 		self._italic+=1
-		self.generate(e.content)
+		self._generate(e.content)
 		self._italic-=1
 		self.write(r"}")
 
@@ -183,7 +183,7 @@ class UCWTexGenerator(OutputGenerator):
 		else:
 			self.write(r"{\bf{}")
 		self._bold+=1
-		self.generate(e.content)
+		self._generate(e.content)
 		self._bold-=1
 		self.write(r"}")
 
@@ -204,7 +204,7 @@ class UCWTexGenerator(OutputGenerator):
 
 	def generate_Note(self, e: Note):
 		self.write(r"\fn{")
-		self.generate(inlinify(e))
+		self._generate(inlinify(e))
 		self.write(r"}")
 
 	def generate_Table(self, e: Table):
@@ -217,11 +217,11 @@ class UCWTexGenerator(OutputGenerator):
 		self.writeln(r"\vskip1em")
 		self.writeln(r"\halign{\strut"+"&".join([aligns[col[0]] for col in e.colspec])+r"\cr")
 		self.indent_more()
-		self.generate(e.head.content)
+		self._generate(e.head.content)
 		self.writeln(r"\noalign{\hrule}")
-		self.generate(e.content[0].content)
+		self._generate(e.content[0].content)
 		self.writeln(r"\noalign{\hrule}")
-		self.generate(e.foot.content)
+		self._generate(e.foot.content)
 		self.indent_less()
 		self.writeln("}")
 		self.writeln(r"\vskip1em")
@@ -230,7 +230,7 @@ class UCWTexGenerator(OutputGenerator):
 		for cell in e.content:
 			if cell.colspan > 1:
 				self.write(r"\multispan"+str(cell.colspan)+"{} ")
-			self.generate(cell.content)
+			self._generate(cell.content)
 			if cell.next:
 				self.write(" & ")
 		self.write(r"\cr")
@@ -245,10 +245,10 @@ class UCWTexGenerator(OutputGenerator):
 			self.writeraw(e.text)
 
 	def generate_Plain(self, e: Plain):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_Span(self, e: Span):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_CodeBlock(self, e: CodeBlock):
 		self.writeln(r"\verbatim{")
@@ -256,15 +256,15 @@ class UCWTexGenerator(OutputGenerator):
 		self.writeln(r"}")
 
 	def generate_Div(self, e: Div):
-		self.generate(e.content)
+		self._generate(e.content)
 
 	def generate_LineBlock(self, e: LineBlock):
 		self.writeln()
-		self.generate(e.content)
+		self._generate(e.content)
 		self.writeln()
 	
 	def generate_LineItem(self, e: LineItem):
-		self.generate(e.content)
+		self._generate(e.content)
 		if e.next:
 			self.write(r"\\")
 		self.endln()
@@ -273,7 +273,7 @@ class UCWTexGenerator(OutputGenerator):
 		self.ensure_empty(2)
 		self.writeln(r"\list{o}")
 		self.indent_more()
-		self.generate(e.content)
+		self._generate(e.content)
 		self.indent_less()
 		self.write(r"\endlist")
 		self.ensure_empty(2)
@@ -298,7 +298,7 @@ class UCWTexGenerator(OutputGenerator):
 		style = delimiters[e.delimiter]
 		self.writeln(r"\list{"+style+r"}")
 		self.indent_more()
-		self.generate(e.content)
+		self._generate(e.content)
 		self.indent_less()
 		self.writeln(r"\endlist")
 		self.ensure_empty(2)
@@ -306,13 +306,13 @@ class UCWTexGenerator(OutputGenerator):
 	def generate_ListItem(self, e: ListItem):
 		self.endln()
 		self.write(r"\:")
-		self.generate(e.content)
+		self._generate(e.content)
 		self.endln()
 
 	def generate_BlockQuote(self, e: BlockQuote):
 		self.writeln(r"\blockquote{")
 		self.indent_more()
-		self.generate(e.content)
+		self._generate(e.content)
 		self.indent_less()
 		self.writeln(r"}")
 
@@ -321,17 +321,17 @@ class UCWTexGenerator(OutputGenerator):
 			self.write(r"\url{")
 		else:
 			self.write(r"\linkurl{"+e.url+r"}{")
-		self.generate(e.content)
+		self._generate(e.content)
 		self.write(r"}") # }
 
 	def generate_Subscript(self, e: Subscript):
 		self.write(r"\subscript{")
-		self.generate(e.content)
+		self._generate(e.content)
 		self.write(r"}")
 
 	def generate_Superscript(self, e: Superscript):
 		self.write(r"\superscript{")
-		self.generate(e.content)
+		self._generate(e.content)
 		self.write(r"}")
 
 	def generate_simple_tag(self, e: Union[Element, None] = None, tag: str = "", attributes: Union[dict[str, str], None] = None, content: Union[ListContainer, Element, list[Union[Element, ListContainer]], str, None] = None, inline: Union[bool, None] = None):