Cheat Sheet

Every operator and option in the .tac language, in one place. For the reasoning
behind each decision see syntax-decisions.md;
for a runnable example see Samples/tachyonn.tac.

Document structure

Syntax	Meaning
=== … ===	Frontmatter block (deck metadata + style keys)
# Title	Section divider slide
## Title	Content slide (a new slide starts here)
## (no text)	Inherits the previous content title
### Title	Highlight box (callout) inside the slide — not a new slide
:: id	Block/slide id, at the end of a header line
// comment	Line comment (also valid in frontmatter)
---	Column separator inside multi-column / grid layouts

Navigation: ↓/→ (and Space/Enter) advance, ↑/← (and
Backspace) go back — all four arrows move linearly through the deck,
consuming pending clicks first. Shift+↓/→ jumps to the next section and
Shift+↑/← to the previous one (sections = # dividers). O opens the
2D overview map (sections as columns, their ## slides stacked below); T
opens the table of contents — every section as a link, jump straight to it.

Inline formatting

Syntax	Result
**bold**	bold
*italic*	italic
***bold italic***	bold italic
~~strike~~	strike
`code`	inline code (literal; variable backtick fences)
H_[2]O	subscript
E = mc^[2]	superscript
+[x^2]	inline math (LaTeX, see Math)
[text]{.class style="…"}	Pandoc span (classes + inline style)

Links

Syntax	Meaning
&[https://site, label]	External link with label
&[https://site]	External link, URL as label
:[idSlide]	Internal link by id
:[idSlide, "label"]	Internal link with a custom label

Images

![<modifiers> src, caption] or ![src]{name=value, …}. Bare filenames are
looked up in ./img/ first, then next to the .tac. A http(s):// URL is
downloaded and cached at compile time into img/.cache/ (and embedded), so
the deck stays offline at render. Use tachyonn export … --refresh-cache (or the
CLI --refresh-cache flag) to re-download; offline, a placeholder is shown.

Shortcut	Named	Meaning
<c>	align=center	Center
<l>	align=left	Left
<r>	align=right	Right
<vc>	valign=center	Vertically centered — the default
<vt>	valign=top	Vertically top
<vb>	valign=bottom	Vertically bottom
<f>	fit=full	Full content width
<h>	fit=half	Half width
<t>	fit=thumb	Thumbnail
<w=N>	width=N	Width (bare number = px; 50%/12vh kept)
<h=N>	height=N	Height
<p=N>	padding=N	Space around the image (all four sides)
<pt=N> <pr=N> <pb=N> <pl=N>	paddingTop= paddingRight= paddingBottom= paddingLeft=	Space on one side
<px=N> <py=N>	paddingX= paddingY=	Space on one axis

Combine in one <> with commas: ![<r, h=80> logo.png].

Housekeeping: tachyonn unused-images deck.tac (or a directory) lists every
file in img/ that no deck in that directory references — with sizes and a
ready-to-run rm line. It scans all .tac/tac.config/.tt/.csv there,
because img/ is shared across sibling decks. --include-cache also checks
img/.cache/.

Pasting an image: tachyonn paste-image deck.tac --row N takes whatever is
on the clipboard — a bitmap (screenshot, "copy image" from a browser) or a file
copied in Finder — writes it into img/ as <deck>-01.png, and inserts the
![…] line after row N. Options: --name, --caption, --modifiers "<c> w=60%",
--no-insert. Bound to cmd-shift-v in the Zed keymap template
(zed-editor/keymap.json).

Vertical alignment only changes anything where the box that hosts the image
is taller than the image itself — in practice, a grid card, which stretches to
the row height. An image alone in a card is centered by default, so you
rarely need to write <vc>; use <vt>/<vb> to pin it to the top or bottom.
Sharing the card with text keeps the normal flow. There is no need to fake it
with pt=/py= anymore.

Lists

Marker	Type
- * +	Unordered
1. 2)	Ordered decimal (. or ) delimiter)
a. A.	Ordered alphabetic (lower/upper)
i. IV.	Ordered roman (lower/upper)

Nest with 2- or 4-space indentation; types can be mixed freely.

Quotes

> A line of quotation.
> — Optional author (last line, em-dash + space)

Tables

Markdown pipe syntax, with an optional options line |<…> before the header.

| Option (on |<…>) | Effect |
|---|---|
| s | Striped rows |
| b | Bordered cells |
| c | Center the whole table |
| lcr… | Global per-column alignment (2+ chars of l/c/r) |

Per-column alignment also via a header-cell prefix <l>/<c>/<r>, or the
separator :--- / :---: / ---:.

Merged cells (colspan/rowspan): a cell containing only < merges into the
cell to its left (extends colspan); a cell containing only ^ merges
into the cell above (extends rowspan). Both chain across consecutive
cells/rows.

| Item   | Q1 | Q2 |
| ------ | -- | -- |
| Totals | <  | (colspan 2, "Totals" spans both columns)

From a CSV file:

Syntax	Effect
|[<f=data.csv>]	Build a table from data.csv (first row = header)
|[<f=data.csv, sep=;>]	Custom field separator
|[<f=data.csv>, s, b, c]	CSV table + the options above

Code blocks

Fenced with triple backticks and a language id. Options go in {…} after the
language.

Option	Effect
highlight=N	Highlight line(s): 2, 2,4, or 2-5
highlight=a|b|c	Incremental: each | group is emphasized on the next click (the last group stays). Adds clicks to the slide.
lineNumbers / ln	Show the gutter; lineNumbers=10 starts at 10
title="…"	Title bar above the code
wrap	Wrap long lines inside the box instead of scrolling horizontally
io	Enable attached input/output sub-boxes (see below)
reveal	With io: reveal code, then input, then output — one click each

Input / output boxes (io): inside the fence, a line --- input or
--- output starts a named sub-box rendered below the code; text after the
marker renames the box (e.g. --- input stdin). Only the code region is
syntax-highlighted. Add reveal to step through them per click.

```python {io, reveal}
n = int(input())
print(n * n)
--- input
5
--- output
25
```

A ```mermaid block is rendered as a diagram (client-side, offline) instead
of highlighted code.

Math (LaTeX / KaTeX)

Syntax	Result
+[E = mc^2]	Inline math
+[<b> \int_0^1 f\,dx]	Display (block) math, like $$…$$

Content is literal TeX; brackets balance, so +[\sqrt[3]{x}] works. Rendered by
KaTeX, bundled offline.

Global macros — define \newcommands once in the frontmatter with texMacro:
(one per line, repeatable) and they apply to every formula in the deck:

texMacro: \newcommand{\R}{\mathbb{R}}
texMacro: \newcommand{\vv}[1]{\mathbf{#1}}
texMacro: \half \frac{1}{2}

Accepts the full \newcommand{\name}[n]{body} form (the [n] is optional — KaTeX
infers argument count from #1…#n), \def, or the short \name expansion.
The same texMacro: line also works inside a .tt theme file, so a theme
(e.g. a "physics" notation pack) can ship its own macros — the deck's own
texMacro: lines win over the theme's on a name clash. A macro whose body
references #2 without #1 (an argument-numbering gap) prints a friendly
warning at compile time.

Highlight boxes (callouts)

### opens a box inside the slide; the text after it is the title bar.

Modifier	Variant
(none) / <s> / <standard>	Standard
<a> / <alert>	Alert
<e> / <example>	Example
<name>	Custom (style via --tac-callout-<name>)

Clicks & animation

The single operators >[…] / <[…] drive per-click reveals.

Syntax	Effect
>[n]{…}	Content enters on click n
<[n]{…}	Visible at first, leaves on click n
>[a-b]{…}	Enters at a, gone by b
>[]{…}	Auto: each child reveals in sequence, continuing the slide's click count (after a >[1] and a >[2], the first automatic child enters on click 3)

The braces take any .tac, including a whole ### box (title bar and all):

>[4]{
###<alert> The uncomfortable truth
Nobody hires you just because you know a language's syntax.
}

A hidden reveal keeps its space — the slide is laid out once, for its final
state, so nothing moves or resizes between clicks (a code block above three
revealed paragraphs is drawn at its final size right away). Set reveal: push
(deck, tac.config or per-slide) for the old behaviour, where a hidden
block-level reveal collapses and the content below slides up.

reveal:	Effect
reserve (default)	Hidden blocks keep their space; layout is identical at every click
push	Hidden blocks collapse; revealing them pushes the content below down

Magic Move: give the destination slide transition: magic and shared
elements fly (FLIP) from their old spot to the new one. Mark them with a
[text]{.magic-NAME} span (same NAME on both slides) or a data-magic
attribute; the slide title morphs automatically. The flight lasts 0.5s by
default — set magicDuration: (e.g. 1.5s, 800ms) on the destination slide
or deck to change it.

Slide transitions

Set transition: once in the deck frontmatter (or in a tac.config, so every
deck in the folder inherits it); a slide's own transition: still wins when you
move forward into it.

===
title: My deck
transition: slide-in        // slide (default) | slide-in | slide-out-in | fade | zoom | none
transitionDuration: 0.6s    // optional, default 0.5s
transitionShift: 12%        // optional, default 10% — travel of the soft families
===

Value	Motion
slide	The classic one: both slides travel a full screen together — you see the old one leave and the new one arrive
slide-in	Only the new slide moves: it drifts in over the old one, fading from transparent to opaque. The old one stays still underneath
slide-out-in	Sequential (like Vue's mode="out-in"): the old slide drifts out and fades, then the new one drifts in
fade	Cross-fade, no movement
zoom	Scale in / out
none	Hard cut

Direction is automatic: horizontal between # sections, vertical between the
## slides of a section, and mirrored when you navigate backwards.

Macros, loops & include

The double operators <<[…] / >>[…] carry structure (no collision with the
single reveal operators). Everything expands at parse time — zero runtime cost.

Syntax	Effect
<<[<name> …body…]	Define a macro/snippet (in tac.config, the frontmatter, or the body)
>>[<name>]	Insert the macro
>>[<name> k=v, …]	Insert with params (available inside as /var[k])
>>[<each> VAR in: a, b, c] … [[/each]]	Loop: repeat the body per value, substituting /var[VAR]
>>[path.tac]	Include another file (its frontmatter is dropped)

Includes are resolved before macros, so a file can be a library of slides
shared by several decks: define the slides once as macros, include the library,
insert them wherever you want them.

// shared/comuns.tac — a library: defining a macro emits nothing by itself
<<[<contato>
## Where to find me                              ::contato

- E-mail: **you@example.org**
- Office: 42, block B
]

<<[<avisos>
## Notices — /var[week]                          ::avisos

- Homework due Friday
- Exam on /var[date]
]

// aula01.tac — any deck that wants them
>>[shared/comuns.tac]

## A slide of this deck's own
…

>>[<avisos> week="1", date=12/08]
>>[<contato>]

Change the library, every deck follows. If a slide needs no variation at all,
skip the macro: put it alone in a file and >>[shared/final.tac] where it goes.

Or skip the include entirely: a macro defined in a tac.config is available
to every deck below it in the tree, exactly like a property. Put the definition
in the course's root tac.config and each lecture only writes >>[<contato>] —
no include line at all. The usual cascade applies: the nearest tac.config
wins over the ones above it, and a definition in the deck itself wins over both.

Two things to know: paths are always relative to the top-level .tac, even
inside a nested include; and a macro body has to keep its [/] balanced (it is
what marks where the body ends).

Directives

/name[arg1, arg2, key=value], inline or on its own line.

Directive	Effect
/layout[name]	Set the slide layout
/notes[…]	Speaker notes (presenter only)
/fn[…]	Footnote
/var[key]	Interpolate a frontmatter value
/cite[id]	Citation
/component[Name, props…]	Embed a registered Vue component (see below)
/icon[]	A Nerd Font glyph — paste the character itself from nerdfonts.com

Components (/component[…])

Registered in tachyonn-render/app/slides/custom-components.ts. Props are
key=value, comma-separated; numbers and true/false are converted to their
real types.

Component	Props	Use
QrCode	url (required), size (px, 260), label, ecl (L/M/Q/H, M), margin (modules, 2), color (#000000), background (#ffffff), showUrl (false)	QR code for a link
Counter	initial (0), step (1)	Click counter (demo)

/component[QrCode, url=https://exemplo.org/aula?turma=2026, label=Slides da aula, size=320]

The QR is drawn as vector SVG, so it stays sharp and weightless in the PDF
export. It is generated offline, on the client — nothing is fetched. A url too
long to encode shows a message on the slide instead of breaking the deck; raise
size and lower ecl if a dense code is hard to scan from the back of the room.

Icons (/icon[…])

Go to nerdfonts.com/cheat-sheet, copy
the glyph itself, and paste it between the brackets:

## /icon[] Deploy
Built with /icon[] and shipped to /icon[].

The Symbols Nerd Font ships inside Tachyonn (MIT), so this works offline, on
any machine, in the PDF and in the network viewer — you do not need a patched
font installed, and the deck's own typography is untouched: only the glyph
changes font.

Works anywhere text goes: slide and section titles, the cover, callout titles,
list items, table cells and footer slots. The icon inherits the color of
wherever it sits (orange in a title, white on a callout bar); iconSize and
iconColor override that.

Layouts (/layout[…])

Name	Use
title	Presentation cover
cover	A full cover slide anywhere in the deck (alias of title; set variant:/image: per-slide)
section	Section divider (from #)
standard	Default (from ##)
two-column / three-column	Columns (split by ---)
image-and-text	Image beside text
big-number	Numeric highlight
quote	Large quotation
grid	Grid of cards (split by ---)
code-window	Full-slide editor-style code
media	Dominant image/video

Frontmatter & style keys

Set in the deck === … ===, in a per-directory tac.config, or per-slide in a
=== … === right after the ## (per-slide wins).

Key (synonyms)	Effect
title subtitle author date	Deck metadata. title/subtitle/author are what the automatic cover shows
description	Deck metadata only — a one-line summary for the footer token {description}. It is not cover content; use coverBody: for that
accent / accentColor	--tac-accent
color / textColor	Base text color
headingColor / titleColor	Headings color
mutedColor borderColor	Muted text / borders
font / fontSans, fontMono / fontCode	Fonts
background / bg	Color, gradient, ![img], or video ![bg.mp4] (autoplays, muted, behind the slide)
overlay / scrim	Legibility veil over the background: dark / light / a number (0.6) / any CSS color
valign	top / center / bottom / between / around
reveal / revealMode / clickMode	How hidden >[n]{…} blocks behave: reserve (default — keep their space, nothing moves between clicks) / push (collapse and push content down)
quoteWidth	Width of the box on a /layout[quote] slide, as a fraction of the slide (default 70%)
theme: NAME	Apply a theme: built-in preset (default, dark, physics) or a .tt file path. physics also ships a TeX macro pack (\ket, \pdv, \R, \norm…)
class / classes	Extra utility classes on the root
textSize slidePadding	Per-slide sizing knobs
transition	Deck-wide default (or per-slide): slide (default) / slide-in / slide-out-in / fade / zoom / none; magic per-slide. Direction (left/right vs. up/down, forward vs. back) is derived from the deck's 2D geometry
transitionDuration	Base duration of the slide transition (e.g. 0.7s; default 0.5s) — deck level
transitionShift / transitionDistance	Travel distance of slide-in / slide-out-in (e.g. 18%; default 10%) — deck level
magicDuration	Magic Move flight duration (e.g. 1.5s, 800ms; default 0.5s)
coverVariant	centered / image-bg / image-title / split / stacked / minimal
coverImage	Cover image or video (a video file plays muted, looping)
coverBody / coverContent	Body of the automatic cover: each occurrence is one line of .tac (repeat the key; an empty one starts a new paragraph). Full syntax — lists, ![img], **bold**, +[math]. \n inside a single key also breaks the line
coverSplitWidth / coverSplit / splitWidth	How much of the slide the media takes on split (width) / stacked (height). Default 50%
coverBodySize coverBodyGap	Text size / top gap of the free body of a /layout[cover] slide
variant (per-slide)	On a cover/title slide: its cover variant; on a # section: that section's variant (overrides sectionVariant)
(body of a /layout[cover] slide)	Rendered in the text column, under title/subtitle/author — paragraphs, lists, an image. The auto-generated deck cover has no body
image (per-slide)	Cover image for a cover/title slide (image-bg routes it to the background)
sectionVariant	centered / toc / toc-side / number / backdrop / color-block / bigtype
kicker (per-section, aliases overline / eyebrow)	Small overline above a # divider's title
sectionBlockColor sectionBlockTextColor sectionBlockSize	color-block: the fill, the text over it, the title size
sectionBigTypeSize	bigtype: the title size (default 7rem)
kickerSize kickerColor kickerFont	Styling of the overline
tocHeading	section / deck / none
toc: false (per-section)	Keep this # section out of the index shown on the section dividers
progress / progressColor	Progress bar position / color
texMacro	Global TeX macro (\newcommand{\R}{\mathbb{R}}); repeatable, works in a .tt theme too
time / duration (per-slide)	Presenter timer target for this slide: seconds (90) or M:SS/H:MM:SS (3:00)
css	Inline CSS rule (repeat to add more)
cssFile / cssFiles	Load .css file(s) next to the .tac
imageMaxWidth imageQuality	Image optimization: resize past N px (default 1920) and re-encode opaque PNGs as JPEG at quality N (82). off embeds originals. This is what keeps exported PDFs small
footer.left footer.center footer.right	Footer slots (text or ![img]); also settable per-slide to override just that slot
footerFont footerSize footerColor	Footer typeface (falls back to the deck font), size (default 13px) and color
iconSize iconColor	Size (1em) and color of /icon[…] glyphs; by default the icon inherits the color where it sits

Footer text tokens: {page} {total} {title} {subtitle} {author}
{date} {description}.

Export

From the app: File → Export PDF… (Cmd/Ctrl+E) opens the print view and the
native dialog (Save as PDF — no Chrome needed). From the CLI:
tachyonn export deck.tac (headless). Both share these options:

CLI flag	Query param	Effect
--steps all|final	steps=final	One page per click (all) vs per slide (final)
--handout CxR	handout=2x2	Handout: C×R slides per sheet
--notes	notes=1	Include speaker notes under each slide
--slides 2-5,8	slides=2-5,8	Export only a subset (1-based)
-o out.pdf	—	Output path (CLI; default <input>.pdf)
--image png|svg	—	One image per slide instead of a PDF (PNG raster or vector SVG)
--out-dir DIR	—	Folder for the images (default <input>-export/)

--image svg wraps each slide in an SVG <foreignObject> (vector, selectable
text); the viewer must support foreignObject (browsers do).