stitch interferes with markdown formatting of code

In this file index.md the first code listing is parsed correctly by stitch, but the second, which is a verbatim code block that should be left to pandoc to handle, is mangled

# Title

Stitch

```{python3, echo=True}
a = 2
b = 3
print(a + b)
```

Verbatim listing

```python
def fn(a, b):
    print("Hello")
    return a + b
```

stitch index.md -o index.html results in an index.html where the verbatim listing is converted to the following html:

<p>def fn(a, b): print(&quot;Hello&quot;) return a + b ```</p>

The expected HTML for that codeblock is

<div class="sourceCode"><pre class="sourceCode python"><code class="sourceCode python"><span class="kw">def</span> fn(a, b):
    <span class="bu">print</span>(<span class="st">&quot;Hello&quot;</span>)
    <span class="cf">return</span> a <span class="op">+</span> b</code></pre></div>

which is what you get when you run pandoc index.md -o index.html.

Any ideas? I’m glad to go digging if this is not work in progress and in scope (and would welcome a pointer in the right direction).

[TomAugspurger]

You’re correct about the intended behavior. Blocks like

```python
def f():
    ...
```

should pass through to pandoc untouched. There’s a slight difficulty here, since by the time we get to the chunk execution / formatting, we’ve sent everything through pandocs internal AST, so the original source has been lost. I think attaching a sentinel value like __stitch__=True to code blocks like

```{lang}
```

should do the trick.

I’ll have a bit more time to look at this in a couple days. Thanks for tracking it down so far!

[kiwi0fruit]

As I understand Stitch tries to work with any code block that has at least one defined css class in attributes:

```python
# do
```

```{.python}
# do
```

```{python}
# do
```

All these varians are the same for Stitch. In Knitty in order to automatically mass-disable code chunks I fixed eval: True global metadata.

Actually you always can use eval=False to have static code samples. I wonder what happen to extra attrs when --to gfm though…