A Quarto extension that enables conditional content blocks based on values defined in _variables.yml — filling a gap not covered by Quarto's built-in .when (which is profile-based only).
Works with all Quarto engines (knitr, Jupyter, Julia, Observable, etc.) since it reads from _variables.yml.
quarto add lsbjordao/quarto-conditional-paramsDefine your variables in _variables.yml at the root of your project:
# _variables.yml
type: detailed
region: south
active: true
year: 2024
report:
audience: public
level: 2Add the filter to your document or project frontmatter:
---
filters:
- conditional-vars
---{{< show-vars >}}Renders a list of all variable names and values from _variables.yml. Useful for debugging.
::: {.when-var type="detailed"}
Shown only when `type` equals `detailed`.
:::::: {.unless-var region="north"}
Shown in every region except `north`.
:::You can use the same logic inline with span attributes:
This text [appears only for detailed reports]{.when-var type="detailed"} in the same paragraph.
This text [is hidden in south region]{.unless-var region="south"}.
Inline OR: [works for `south` or `north`]{.when-var region="south|north"}.
Inline numeric: [shown when year is >= 2024]{.when-var year=">=2024"}.
Inline numeric range (50% <= support_pct < 60%):
[in range]{.when-var support_pct=">=50&<60"}
Support by percentage (`support_pct`):
[weak support]{.when-var support_pct="<40"}
[moderate support]{.when-var .unless-var when-support_pct=">=40" unless-support_pct=">=70"}
[strong support]{.when-var support_pct=">=70"}when-<var> and unless-<var> prefixes also work inline when both classes are present.
You can also combine constraints for the same variable with & (AND), and combine alternatives with | (OR).
All attributes must match simultaneously.
::: {.when-var type="detailed" region="south"}
Shown only when `type` is `detailed` and `region` is `south`.
:::Any value in the list is sufficient to match.
::: {.when-var type="detailed|summary"}
Shown when `type` is `detailed` or `summary`.
:::Works with numeric conditions too:
::: {.when-var year=">2025|<2020"}
Shown when `year` > 2025 or `year` < 2020.
:::Supports >, >=, <, <= operators, and & for AND ranges.
::: {.when-var year=">2020"}
Shown when `year` > 2020.
:::
::: {.when-var year=">=2024"}
Shown when `year` >= 2024.
:::
::: {.when-var year="<2024"}
Shown when `year` < 2024.
:::
::: {.when-var year="<=2023"}
Shown when `year` <= 2023.
:::
::: {.when-var year=">=2020&<2025"}
Shown when `year` is in [2020, 2025).
:::
::: {.when-var year=">=2025&<2030"}
Shown when `year` is in [2025, 2030).
:::
::: {.when-var year=">=2020&<2023|>=2024&<2026"}
Shown when `year` is in [2020, 2023) or [2024, 2026).
:::
::: {.when-var year=">=2010&<2015|>=2030&<2035"}
Shown when `year` is in [2010, 2015) or [2030, 2035).
:::::: {.when-var active="true"}
Shown only when `active` is `true`.
:::Nested mappings in _variables.yml are accessible with dot notation.
# _variables.yml
report:
audience: public
level: 2::: {.when-var report.audience="public"}
Shown only when `report.audience` is `public`.
:::
::: {.when-var report.level=">=2"}
Shown when `report.level` >= 2.
:::When both classes are present, use when-<var> and unless-<var> prefixes to declare each condition explicitly.
::: {.when-var .unless-var when-type="detailed" unless-region="north"}
Shown when `type` is `detailed` and `region` is not `north`.
:::A reference to a variable that does not exist evaluates to false (block hidden) and prints a warning to the console:
::: {.when-var country="Brazil"}
Shown only when `country` equals `Brazil`.
:::WARNING [conditional-vars]: unknown variable 'country' referenced in .when-var / .unless-var
Quarto's .when conditional content supports profiles and other build-time conditions, but cannot evaluate conditions based on variable values. This extension enables conditional content driven directly by _variables.yml, allowing variable-aware rendering workflows that work across all document engines.
MIT © Lucas S.B. Jordão