Code Blocks

The perhaps biggest reason why you are using nimiSlides is that you want to show off some Nim code. Showing a code block and optionally its printed output is done using the nbCode or nbCodeInBlock templates. The difference is that nbCode does not open a new scope, and as such variables defined in a nbCode block can be accessed in later blocks. nbCodeInBlock on the other hand opens a new block and the variables defined there can't be accessed outside it. This is important because nbCodeInBlock will allow us to reuse the same variable name multiple times. Here's an example where both are used:

slide:
  nbCode:
    let x = 1
    let y = 2
    echo x + y
slide:
  nbCodeInBlock:
    let a = 10
    # note that x is from the previous nbCode block:
    echo a + x

let x = 1
let y = 2
echo x + y

3

let a = 10
# note that x is from the previous nbCode block:
echo a + x

11

We can see that both the code and the echo'd 3 is shown on the first slide. And on the second slide we can see that we access x because it was defined in a nbCode block.

But what if we don't want to show the output? Either because it is too long or just irrelevant. Then we can use nbClearOutput() directly after the call to nbCode/nbCodeInBlock:

slide:
  nbCodeInBlock:
    let x = 1
    let y = 2
    echo x + y
  nbClearOutput()

let x = 1
let y = 2
echo x + y

Poof! The output is gone!

Animated Code Blocks

One cool feature of Reveal.js is the animated code blocks. It allows you to create a code block like the ones we have created above, but highlight specific lines. This is done using the animateCode template by providing which lines to highlight and in which order. The lines can be specified either as a slice x..y, a single line number x, or a set of lines {x, y}. Note that the first line has line number 1 (and not 0).

slide:
  animateCode(1, 2..3, 5, {2, 4}):
    let x1 = 1
    let x2 = 2
    let x3 = 3
    let x4 = 4
    let x5 = 5

let x1 = 1
let x2 = 2
let x3 = 3
let x4 = 4
let x5 = 5

As you can see, first line 1 is highlighted, then lines 2 through 3, then line 5 and lastly line 2 through 4. Neat! Note that there exists no animateCodeInBlock currently, but you can always wrap your animateCode inside a block: to get the same effect. The animated code block is also useful if you have a very long code snippet that you want to show as it will auto-scroll for you:

slide:
  animateCode(1, 16, 5, 13, 1):
    let y1 = 1
    let y2 = 2
    let y3 = 3
    let y4 = 4
    let y5 = 5
    let y6 = 6
    let y7 = 7
    let y8 = 8
    let y9 = 9
    let y10 = 10
    let y11 = 11
    let y12 = 12
    let y13 = 13
    let y14 = 14
    let y15 = 15
    let y16 = 16

let y1 = 1
let y2 = 2
let y3 = 3
let y4 = 4
let y5 = 5
let y6 = 6
let y7 = 7
let y8 = 8
let y9 = 9
let y10 = 10
let y11 = 11
let y12 = 12
let y13 = 13
let y14 = 14
let y15 = 15
let y16 = 16