Code highlighting

Code highlighting is supported for the following languages:

ada
asp
awk
bash
batchfile
C
cmake
crontab
C#
clojure
C++
CSS
D
diff
docker
dotenv
elixir
elm
erlang
go
haskell
HTML
java
javascript
json
kotlin
latex
lua
makefile
markdown
nix
ocaml
perl
php
protobuf
puppet
python
R
ruby
rust
scala
shell
sql
swift
svelte
terraform
typescript
xml
yaml
vue
zig

Enabling line numbers

If you would like line numbers to be shown on the left of a code block use the +line_numbers switch after specifying the language in a code block:

```rust +line_numbers
   fn hello_world() {
       println!("Hello world");
   }
```

By default, the entire code block will be syntax-highlighted. If instead you only wanted a subset of it to be highlighted, you can use braces and a list of either individual lines, or line ranges that you'd want to highlight.

```rust {1,3,5-7}
   fn potato() -> u32 {         // 1: highlighted
                                // 2: not highlighted
       println!("Hello world"); // 3: highlighted
       let mut q = 42;          // 4: not highlighted
       q = q * 1337;            // 5: highlighted
       q                        // 6: highlighted
   }                            // 7: highlighted
```

Dynamic highlighting

Similar to the syntax used for selective highlighting, dynamic highlighting will change which lines of the code in a code block are highlighted every time you move to the next/previous slide.

This is achieved by using the separator | to indicate what sections of the code will be highlighted at a given time.

```rust {1,3|5-7}
   fn potato() -> u32 {

       println!("Hello world");
       let mut q = 42;
       q = q * 1337;
       q
   }
```

In this example, lines 1 and 3 will be highlighted initially. Then once you press a key to move to the next slide, lines 1 and 3 will no longer be highlighted and instead lines 5 through 7 will. This allows you to create more dynamic presentations where you can display sections of the code to explain something specific about each of them.

See this real example of how this looks like.

Executing code

Annotating a shell code block with a +exec switch will make it executable. Once you're in a slide that contains an executable block, press control+e to execute it. The output of the execution will be displayed on a box below the code. The code execution is stateful so if you switch to another slide and then go back, you will still see the output.

```bash +exec
echo hello world
```

Note that using bash, zsh, fish, etc, will end up using that specific shell to execute your script.

Note: because this is spawning a process and executing code, you should use this at your own risk.

Pre-rendering

Some languages support pre-rendering. This means the code block is transformed into something else when the presentation is loaded. The languages that currently support this are LaTeX and typst where the contents of the code block is transformed into an image, allowing you to define formulas as text in your presentation. This can be done by using the +render attribute on a code block.

See the LaTeX and typst docs for more information.

presenterm documentation