Robustify xymatrix rendering and improve nowiki handling

We make some tweaks to the xymatrix diagram renderer to allow it to
handle correctly a wider range of cases: curved arrows for example. We
move from \xymatrix{...} to \begin{xymatrix} ... \end{xymatrix} to
make it easier to detect the diagram correctly when mathematics is
used inside it.

We also tweak the <nowiki>...</nowiki> renderer and the way it is
called in certain cases to allow Tikz and Xymatrix diagram code, as
well as centred code, to be able to be displayed verbatim.

script/author_to_user

@@ -2,3 +2,4 @@ Bas Spitters, spitters
 Max S. New, maxsnew
 N. Raghavendra, raghu
 Nyshadham Raghavendra, raghu
+Pieter Cuijpers, Pieter

script/src/diagrams/diagram.py

@@ -29,6 +29,10 @@
 logging_file_handler.setFormatter(logging_formatter)
 logger.addHandler(logging_file_handler)
 
+class DocumentParametersException(Exception):
+    def __init__(self, message):
+        super().__init__(message)
+
 class PdfRenderingException(Exception):
     def __init__(self, message):
         super().__init__(message)
@@ -95,11 +99,56 @@ def tikz_tex_source(diagram, is_commutative_diagram):
             tikz_libraries = "\\usetikzlibrary{cd}",
             tikz_diagram = diagram)
 
+def parse_document_parameters(document_parameters):
+    parsed_parameters = { "document_header_parameters": [ "12pt" ] }
+    for parameter in document_parameters.split(","):
+        split_at_equals = parameter.split("=")
+        if len(split_at_equals) != 2:
+            raise DocumentParametersException(
+                "The following does not have the expected format: " +
+                parameter)
+        key = split_at_equals[0].strip()
+        value = split_at_equals[1].strip()
+        if key == "font":
+            parsed_parameters["font_size"] = value
+        elif key == "border":
+            parsed_parameters["document_header_parameters"].append(parameter)
+        else:
+            raise DocumentParametersException(
+                "The key " +
+                key +
+                " of the following parameter is not recognised: " +
+                parameter)
+    return parsed_parameters
+
+def extract_document_parameters(diagram):
+    split_at_first_curly_brace = diagram.split("{", 1)
+    document_parameters = {
+        "font_size": "",
+        "document_header_parameters": ["12pt"] }
+    document_parameters_block = find_block.Block(
+        "[",
+        "]",
+        lambda within_square_brackets: document_parameters.update(
+            parse_document_parameters(within_square_brackets)),
+        False)
+    document_parameters_processor = find_block.Processor([
+        document_parameters_block])
+    processed_preamble = document_parameters_processor.process(
+        split_at_first_curly_brace[0])
+    return (
+        document_parameters,
+        processed_preamble + "{" + split_at_first_curly_brace[1])
+
 def xypic_tex_source(diagram):
+    document_parameters, diagram = extract_document_parameters(diagram)
     xypic_diagram_template_path = os.environ["NLAB_XYPIC_DIAGRAM_TEMPLATE"]
     with open(xypic_diagram_template_path, "r") as xypic_diagram_template_file:
         xypic_diagram_template = xypic_diagram_template_file.read()
         return string.Template(xypic_diagram_template).substitute(
+            document_parameters = ", ".join(
+                document_parameters["document_header_parameters"]),
+            font_size = document_parameters["font_size"],
             xypic_diagram = diagram)
 
 def create_pdf(
@@ -207,8 +256,15 @@ def main():
             "\nThe error was: " +
             str(svgRenderingException))
         sys.exit(message)
+    except DocumentParametersException as documentParametersException:
+        message = (
+            "An error occurred when rendering the following diagram. \n" +
+            diagram +
+            "\n " +
+            str(documentParametersException))
+        logger.warning(message)
+        sys.exit(message)
     except Exception as exception:
-        raise exception
         message = (
             "An unexpected error occurred when creating an SVG from a PDF " +
             "for the following diagram. \n" +

script/src/diagrams/xypic_diagram_template

@@ -1,9 +1,13 @@
-\documentclass[12pt]{standalone}
+\documentclass[$document_parameters]{standalone}
 
-\usepackage[all]{xy}
+\usepackage[all, 2cell]{xy}
+
+\UseTwocells
 
 \begin{document}
 
+$font_size
+
 $xypic_diagram
 
 \end{document}

script/src/renderer/centre_block.py

@@ -5,6 +5,7 @@
 """
 
 import find_block
+import nowiki_block
 
 def initial_centre_processor(content):
     return (
@@ -33,8 +34,11 @@ def define_centre():
         True)
 
 def handle_initial_centring(content):
-    return find_block.Processor([define_center(), define_centre()]).process(
-        content)
+    processor = find_block.Processor([
+        define_center(),
+        define_centre(),
+        nowiki_block.define(True)])
+    return processor.process(content)
 
 def handle_post_centring(content):
     centre_paragraph_block = find_block.Block(

script/src/renderer/nowiki_block.py

@@ -6,14 +6,14 @@
 """
 import find_block
 
-def nowiki_processor(nowiki_content):
-    if "[[!include" in nowiki_content:
+def nowiki_processor(nowiki_content, retain_nowiki_block):
+    if retain_nowiki_block or ("[[!include" in nowiki_content):
         return "<nowiki>" + nowiki_content + "</nowiki>"
     return nowiki_content
 
-def define():
+def define(retain_nowiki_block = False):
     return find_block.Block(
         "<nowiki>",
         "</nowiki>",
-        nowiki_processor,
+        lambda content: nowiki_processor(content, retain_nowiki_block),
         True)

script/src/renderer/tikz_diagram_block.py

@@ -7,6 +7,7 @@
 import find_block
 import os
 import subprocess
+import nowiki_block
 
 class TikzDiagramException(Exception):
     def __init__(self, message):
@@ -66,7 +67,9 @@ def define_tikz_commutative_diagram():
         True)
 
 def handle_tikz_diagrams(content):
-    processor = find_block.Processor(
-        [ define_tikz(), define_tikz_commutative_diagram() ])
+    processor = find_block.Processor([
+        define_tikz(),
+        define_tikz_commutative_diagram(),
+        nowiki_block.define(True) ])
     return processor.process(content)
 

script/src/renderer/xypic_diagram_block.py

@@ -7,15 +7,23 @@
 import find_block
 import os
 import subprocess
+import nowiki_block
 
 class XyPicDiagramException(Exception):
     def __init__(self, message):
         super().__init__(message)
 
+def remove_new_lines_at_start_of_block(diagram):
+    split_at_opening_brace = diagram.split("}", 1)
+    if len(split_at_opening_brace) == 0:
+        raise XyPicDiagramException(
+            "Missing end brace } after \\begin{xymatrix")
+    return split_at_opening_brace[0] + "{" + split_at_opening_brace[1].strip()
+
 def xypic_diagram_processor(xypic_diagram):
     xypic_diagram = (
         "\\xymatrix@" +
-        xypic_diagram +
+        remove_new_lines_at_start_of_block(xypic_diagram) +
         "}")
     diagram_api_path = os.environ["NLAB_DIAGRAM_API_PATH"]
     completed_xypic_diagram_process = subprocess.run(
@@ -30,21 +38,32 @@ def xypic_diagram_processor(xypic_diagram):
 
 def define_xymatrix_default_size():
     return find_block.Block(
-        "\\xymatrix{",
-        "}",
+        "\\begin{xymatrix}",
+        "\\end{xymatrix}",
+        lambda diagram: xypic_diagram_processor(
+            "=5em}" + diagram),
+        True)
+
+def define_xymatrix_document_parameters():
+    return find_block.Block(
+        "\\begin{xymatrix[",
+        "\end{xymatrix}",
         lambda diagram: xypic_diagram_processor(
-            "=5em{" + diagram),
+            "=5em[" + diagram),
         True)
 
 def define_xymatrix():
     return find_block.Block(
-        "\\xymatrix@",
-        "}",
+        "\\begin{xymatrix@",
+        "\\end{xymatrix}",
         xypic_diagram_processor,
         True)
 
 def handle_xypic_diagrams(content):
-    processor = find_block.Processor(
-        [ define_xymatrix(), define_xymatrix_default_size() ])
+    processor = find_block.Processor([
+        define_xymatrix(),
+        define_xymatrix_default_size(),
+        define_xymatrix_document_parameters(),
+        nowiki_block.define(True) ])
     return processor.process(content)