Just a Theory

This repository contains the source code for Just a Theory, a periodically irregular technology and culture blog by David E. Wheeler.

Just a Theory is written in Markdown, built and published with Hugo, and hosted on AWS. It's set in Source Sans Pro, with fixed-width type set in Source Code Pro. The icons are by Font Awesome.

The site eschews JavaScript, and uses no tracking or analytics services.

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Reference

Some notes for myself to refer to on how to use some of the shortcodes in this project.

Link

The Link shortcode resolves a link to a static file, such as a tarball, PDF, patch, or image. It takes a single argument: the file or URL to link to. It uses the following heuristics to determine how to render the link:

• If the link starts with /, it is assumed to be an absolute link on the site. It will be rendered with the site base URL prefixed to it.
• If the link contains :// or starts with //, it's assumed to be a full URL and is simply output as such. This option isn't generally used directly, but implicitly by the figure shortcode below.
• Otherwise the link is assumed to be a file name in the same directory as the current page. It will be prefixed with the full URL of the current page.

Examples:

{{% link "/downloads/TestBuilder-0.01.tar.gz" %}}
{{% link "learning_plpgsql.pdf" %}}

Note that links to assets in other page bundles are not supported for various reasons. In other words, this will not work and cannot (easily) be made to work:

{{% link "/post/postgres/extension-ecosystem-summit/summit.jpeg" %}}

Instead move such shared images to the static directory with and use an absolute path, or just use the absolute path to the other post:

{{% link "/2024/02/extension-ecosystem-summit/summit.jpeg" %}}

Or use a ref to the original package (in which case link isn't needed at all):

{{% ref "/post/postgres/extension-ecosystem-summit" %}}summit.jpeg

Although this option is not available in front matter.

Ref

The Ref shortcode comes with Hugo, and links to a document in the current project. Pass a single argument, the path to the document, as the sole argument. Use the absolute path starting from a subdirectory of the content/ directory, and omit the .md or /index.md from the file name (unless the file name contains other . characters, in which case the full file name should remain).

An optional second argument specifies an alternate output format.

Examples:

  [#extensions]: https://postgresteam.slack.com/archives/C056ZA93H1A
    "Postgres Slack/#extensions: Extensions and extension-related accessories"
  [Postgres Slack]: https://pgtreats.info/slack-invite
    "Join the Postgres Slack"
{{% ref "/post/books/project-hail-mary" "text" %}}
{{% ref "/post/past/js/test-simple-0.03.md" %}}
{{% ref "/photo/nyc/harlem-steps" %}}
{{% ref "/" "json" %}}

Param

The Param shortcode comes with Hugo and emits data from site parameters --- basically the stuff under [params] in config.toml. Examples:

[my GitHub]: https://github.com/{{% param "github" %}}
[on Mastodon]: {{% param "mastodon.url" %}} "{{% param "mastodon.user" %}}"

Syntax Highlighting

Syntax Highlighting comes with Hugo. Use fenced blocks with the named language, e.g.,

func main() {}

An optional second argument takes a comma-delimited list of key=value option pairs, e.g.,

``` go {linenos=table,hl_lines=[8,"15-17"],linenostart=199}
// ... code
```

The supported options are:

• linenos: configure line numbers. Valid values are true, false, table, or inline. false will turn off line numbers if it’s configured to be on in site config. New in v0.60.0: table will give copy-and-paste friendly code blocks.
• hl_lines: lists a set of line numbers or line number ranges to be highlighted.
• linenostart=199: starts the line number count from 199.
• anchorlinenos: Configure anchors on line numbers. Valid values are true or false;
• lineanchors: Configure a prefix for the anchors on line numbers. Will be suffixed with -, so linking to the line number 1 with the option lineanchors=prefix adds the anchor prefix-1 to the page.

Figure

The Figure shortcode and partial use the same syntax, to create an image figure and caption in HTML and plain text. For photos type posts, the HTML output image will also be zoomable to the full width of the browser window by tapping the image --- unless link is set.

Can also be used as an object for the image key in the front matter of a post, in which case it will be included in the HTML metadata fore configuring articles previews on social media, as well as above the body copy of the post. The parameters are:

src

The image source URL. May be a local URL, which will be resolved by the Link shortcode. Required.

link

A URL to link the image to. May be a local URL, which will be resolved by the Link shortcode. Optional.

class

A string with the CSS class or classes to use for the figure. Optional. Values are:

• frame - Wrap the figure in a dark background frame
• left - Float the figure to the left of text
• right - Float the figure to the right of text
• center - Center the figure
• clear - Make the background transparent instead of white

title

Image title. Not used in plain text output unless alt is not set. Markdown within the value of title will be rendered. Optional.

alt

Alt text for the title, generally text describing the image for those who cannot see it. Optional.

target

Set the target attribute of the link. Only used if link is set. Optional.

rel

Set the rel attribute of the link. Only used if link is set. Optional.

width

Set the width attribute of the image. Optional.

height

Set the height attribute of the image. Optional.

heading

Sets the value for a heading (rendered as <h4>) in the caption. Markdown within the value of caption will be rendered. Optional.

caption

Text for the caption. Markdown within the value of caption will be rendered. Optional.

attr

Text to use for attribution, for when the photo comes from elsewhere. Markdown within the value of attr will be rendered. Optional.

copyright

Text to use for a copyright notice. Will be preceded by the copyright symbol. Markdown within the value of copyright will be rendered. Optional.

metaOnly

Used only for the image: front matter. When set to true, prevents the figure from being rendered above the body of the post. Useful if the image is used elsewhere in the post, but you still want it to appear in metadata for previews on social media.