Fix bug: can handle empty text nodes in Xournal++

.gitignore

@@ -1 +1,2 @@
-__pycache__/
+__pycache__/
+*.egg-info/

flake.lock

@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1681202837,
+        "narHash": "sha256-H+Rh19JDwRtpVPAWp64F+rlEtxUWBAQW28eAi3SRSzg=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "cfacdce06f30d2b68473a46042957675eebb3401",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1683014792,
+        "narHash": "sha256-6Va9iVtmmsw4raBc3QKvQT2KT/NGRWlvUlJj46zN8B8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1a411f23ba299db155a5b45d5e145b85a7aafc42",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,13 @@
+{
+  inputs = {
+    nixpkgs.url = github:NixOS/nixpkgs/nixos-unstable;
+    flake-utils.url = github:numtide/flake-utils;
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system: {
+      defaultPackage = (import ./default.nix) { pkgs = nixpkgs.legacyPackages.${system}; };
+    });
+
+  nixConfig.bash-prompt-prefix = "\\e\[94;1m[xopp2py]\\e\[m ";
+}

src/xopp2oml/README.md

@@ -2,4 +2,4 @@
 
 This exporter generates OML descriptions that use the following vocabulary:
 
-https://msdl.uantwerpen.be/git/lucasalbertins/DTDesign/src/d070f9e9e932ad9910eaab92eabc368e7ee96058/examples/oml/CDF/src/oml/flandersmake.be/cdf/vocabulary/xopp.oml
+https://msdl.uantwerpen.be/git/lucasalbertins/DTDesign/src/15c791c78589f9c064fc402feec5228b5a80f549/examples/oml/CDF/src/oml/flandersmake.be/cdf/vocabulary/xopp.oml

src/xopp2oml/template.oml

@@ -1,68 +1,69 @@
-{%- macro attributes(pageindex, page, layerindex, layer, elementindex, element) -%}
-{%- for key,value in element.attributes.items() %}
-  ci p{{pageindex}}l{{layerindex}}e{{elementindex}}a{{loop.index}} : xopp:XMLAttribute [
-    xopp:hasKey "{{key}}"
-    xopp:hasValue "{{value}}"
-    xopp:ofLayerElement p{{pageindex}}l{{layerindex}}e{{elementindex}}
-    object_diagram:inModel model
-  ]
-{% endfor %}
-{%- endmacro -%}
-
-{%- macro elements(pageindex, page, layerindex, layer) -%}
-{% for el in layer.elements %}
-  ci p{{pageindex}}l{{layerindex}}e{{loop.index}} : xopp:{{el.__class__.__name__}} [
-    xopp:hasText "{{el.text}}"
-    xopp:inLayer p{{pageindex}}l{{layerindex}}
-    object_diagram:inModel model
-  ]
-  {{ attributes(pageindex, page, layerindex, layer, loop.index, el) -}}
-{% endfor %}
-{%- endmacro -%}
-
-{%- macro layers(pageindex, page) -%}
-{% for layer in page.layers %}
-  ci p{{pageindex}}l{{loop.index}} : xopp:Layer [
-    xopp:inPage p{{pageindex}}
-    object_diagram:inModel model
-  ]
-  {{ elements(pageindex, page, loop.index, layer) -}}
-{% endfor %}
-{%- endmacro -%}
-
-{%- macro pages(file) -%}
-{% for page in file.pages -%}
-  ci p{{loop.index}} : xopp:Page [
-    xopp:hasWidth {{ page.width }}
-    xopp:hasHeight {{ page.height }}
-    xopp:hasBackgroundType "{{ page.background_type }}"
-    xopp:hasBackgroundColor "{{ page.background_color }}"
-    xopp:hasBackgroundStyle "{{ page.background_style }}"
-    xopp:inFile file
-    object_diagram:inModel model
-  ]
-  {{ layers(loop.index, page) -}}
-{%- endfor %}
-{%- endmacro -%}
 // Warning: Generated code! Do not edit!
 // Input file: '{{inputfile}}'
 // Generator: https://msdl.uantwerpen.be/git/jexelmans/xopp2py
-description <http://flandersmake.be/cdf/description/{{namespace}}#> as {{namespace}} {
+{%- if minimal %}
+// Minimal mode enabled: All XML attributes and non-text nodes are omitted.
+{%- endif %}
 
-  uses <http://flandersmake.be/cdf/vocabulary/xopp#> as xopp
+description <{{output_namespace}}#> as {{shorthand}} {
-  uses <http://flandersmake.be/cdf/vocabulary/object_diagram#> as object_diagram
 
-  ci model : xopp:Model []
+  uses <{{namespaces.xopp}}#> as xopp
+  uses <{{namespaces.object_diagram}}#> as object_diagram
+  {%- if not minimal %}
+  uses <{{namespaces.dict}}#> as dict
+  {%- endif %}
 
-  ci file : xopp:File [
+  ci model : xopp:Model [
-    xopp:hasCreator "{{ file.creator }}"
+    object_diagram:hasName "{{shorthand}}"
+    xopp:hasCreator {{ file.creator | to_oml_string_literal }}
     xopp:hasFileVersion {{ file.fileversion }}
-    xopp:hasTitle "{{ file.title }}"
+    xopp:hasTitle {{ file.title | to_oml_string_literal }}
     {%- if file.preview != None %}
-    xopp:hasPreview "{{ toBase64(file.preview).decode('utf-8') }}"
+    xopp:hasPreview {{ file.preview | to_base64_string }}
     {%- endif %}
+  ]
+
+  {%- for page_index, page in enumerate(file.pages) %}
+
+  ci p{{page_index}} : xopp:Page [
+    xopp:hasWidth {{ page.width }}
+    xopp:hasHeight {{ page.height }}
+    xopp:hasBackgroundType {{ page.background_type | to_oml_string_literal }}
+    xopp:hasBackgroundColor {{ page.background_color | to_oml_string_literal }}
+    xopp:hasBackgroundStyle {{ page.background_style | to_oml_string_literal }}
+    xopp:inFile model
     object_diagram:inModel model
   ]
 
-  {{ pages(file) }}
+  {%- for layer_index, layer in enumerate(page.layers) %}
+
+  ci p{{page_index}}l{{layer_index}} : xopp:Layer [
+    xopp:inPage p{{page_index}}
+    object_diagram:inModel model
+  ]
+
+  {%- for el_index, el in enumerate(layer.elements) %}
+  {%- if not minimal or el.__class__.__name__ == "Text" and el.text != None %}
+
+  ci p{{page_index}}l{{layer_index}}e{{el_index}} : xopp:{{el.__class__.__name__}} [
+    xopp:hasText {{el.text | to_oml_string_literal}}
+    xopp:inLayer p{{page_index}}l{{layer_index}}
+    object_diagram:inModel model
+  ]
+
+  {%- if not minimal %}
+  {%- for key, value in el.attributes.items() %}
+
+  ci p{{page_index}}l{{layer_index}}e{{el_index}}a{{loop.index}} : xopp:XMLAttribute [
+    dict:hasKey {{key | to_oml_string_literal}}
+    dict:hasValue {{value | to_oml_string_literal}}
+    xopp:ofLayerElement p{{page_index}}l{{layer_index}}e{{el_index}}
+    object_diagram:inModel model
+  ]
+  {%- endfor %}
+  {%- endif %}
+  {%- endif %}
+  {%- endfor %}
+  {%- endfor %}
+  {%- endfor %}
 }

src/xopp2oml/writer.py

@@ -1,18 +1,69 @@
 from xopp2py import abstract_syntax
 import io
+import base64
 
-def writeOML(xournalFile: abstract_syntax.XournalFile, inputfile:str, namespace:str, ostream: io.TextIOBase):
+CDF_NAMESPACES = {
+    # namespace of generated description
+    "description": "http://flandersmake.be/cdf/description/my_xopp",
+    "shorthand": "my_xopp",
+
+    # vocabulary namespaces
+    "xopp": "http://flandersmake.be/cdf/vocabulary/xopp",
+    "object_diagram": "http://flandersmake.be/cdf/vocabulary/object_diagram",
+    "dict": "http://flandersmake.be/cdf/vocabulary/dict",
+}
+
+DTDESIGN_NAMESPACES = {
+    # namespace of generated description
+    "description": "http://ua.be/sdo2l/description/artifacts/my_xopp",
+    "shorthand": "my_xopp",
+
+    # vocabulary namespaces
+    "xopp": "http://ua.be/sdo2l/vocabulary/formalisms/xopp",
+    "object_diagram": "http://ua.be/sdo2l/vocabulary/formalisms/object_diagram",
+    "dict": "http://ua.be/sdo2l/vocabulary/formalisms/dict",
+
+    "artifacts": "http://ua.be/sdo2l/description/artifacts/",
+}
+
+def to_oml_string_literal(python_string):
+    # Not sure which characters to escape in OML.
+    # At the very least, quotes should be escaped:
+    return '"' + python_string.replace('"', '\\"') + '"'
+
+def to_base64_string(bytes):
+    return '"' + base64.b64encode(bytes).decode('utf-8') + '"'
+
+def writeOML(
+    xournalFile: abstract_syntax.XournalFile,
+    inputfile:str,
+    model_name: str,
+    ostream: io.TextIOBase,
+    namespaces=DTDESIGN_NAMESPACES):
+    """ Write out a Xournal++ file as an OML description.
+    Parameters:
+        xournalFile: abstract syntax of a parsed .xopp file
+        inputfile: name of input file (only for documentation/traceability purposes - any value can be used here)
+        model_name: used to determine the namespace of the generated OML description
+        namespace: namespace of xopp-OML-vocabulary
+        ostream: output stream to write to
+    """
     import jinja2
     import os
-    import base64
 
     environment = jinja2.Environment(
         loader=jinja2.FileSystemLoader(os.path.dirname(__file__)))
 
+    environment.filters['to_oml_string_literal'] = to_oml_string_literal
+    environment.filters['to_base64_string'] = to_base64_string
+
     template = environment.get_template("template.oml")
     for piece in template.generate(
+        minimal=True,
         file=xournalFile,
-        toBase64=base64.b64encode,
         inputfile=inputfile,
-        namespace=namespace):
+        enumerate=enumerate,
-        ostream.write(piece)
+        output_namespace=namespaces['artifacts']+model_name+"_xopp",
+        shorthand=model_name+"_xopp",
+        namespaces=namespaces):
+            ostream.write(piece)