Inline code reference previews

build/Filters.hs

@@ -11,6 +11,7 @@ import           Text.Pandoc.Definition (Pandoc)
 import qualified Filters.Sidenotes  as Sidenotes
 import qualified Filters.Typography as Typography
 import qualified Filters.Links      as Links
+import qualified Filters.SourceRefs as SourceRefs
 import qualified Filters.Smallcaps  as Smallcaps
 import qualified Filters.Dropcaps   as Dropcaps
 import qualified Filters.Math       as Math
@@ -32,7 +33,8 @@ import qualified Filters.Aftermatter as Aftermatter
 --   resolution of co-located assets.
 applyAll :: FilePath -> Pandoc -> IO Pandoc
 applyAll srcDir doc = do
-    imagesDone <- Images.apply srcDir doc
+    imagesDone     <- Images.apply     srcDir doc
+    sourceRefsDone <- SourceRefs.apply imagesDone
     pure
         . Aftermatter.apply
         . Sidenotes.apply
@@ -42,7 +44,7 @@ applyAll srcDir doc = do
         . Dropcaps.apply
         . Math.apply
         . Code.apply
-        $ imagesDone
+        $ sourceRefsDone
 
 -- | Apply source-level preprocessors to the raw Markdown string.
 --   Order matters: EmbedPdf must run before Transclusion, because the

build/Filters/Links.hs

@@ -43,6 +43,12 @@ classifyPdfLink (Link (ident, classes, kvs) ils (url, title))
 classifyPdfLink x = x
 
 classifyLink :: Inline -> Inline
+classifyLink l@(Link (_, classes, _) _ _)
+    -- Source-ref links are owned by Filters.SourceRefs: they keep the
+    -- inline-code chrome of their body, must not receive an external
+    -- brand icon stamp, and have their own popup provider. Leave them
+    -- entirely alone.
+    | "source-ref" `elem` classes = l
 classifyLink (Link (ident, classes, kvs) ils (url, title))
     | isExternal url =
         let icon     = domainIcon url

build/Filters/SourceRefs.hs

@@ -0,0 +1,193 @@
+{-# LANGUAGE GHC2021 #-}
+{-# LANGUAGE OverloadedStrings #-}
+-- | Detect repo-relative source-file references in prose and wrap them
+--   in a link that triggers a hover-preview popup of the file's contents.
+--
+--   Two trigger forms:
+--
+--   * Inline @\`build\/Filters\/Links.hs\`@ — Markdown inline code whose
+--     text passes a conservative source-path heuristic.
+--   * A Markdown link to
+--     @https:\/\/git.levineuwirth.org\/neuwirth\/levineuwirth.org\/(src|raw)\/branch\/<branch>\/<path>@.
+--
+--   Both produce
+--   @\<a class="source-ref" data-source-path="…" href="…">@. The href
+--   points to the Forgejo source viewer so a click without JS — or a
+--   popup that fails to fetch — still resolves to a useful target.
+--   The popup provider in @static\/js\/popups.js@ fetches
+--   @\/source\/\<path\>@ (a same-origin copy emitted by the Hakyll
+--   source-preview rule in 'Site.rules') and renders a
+--   syntax-highlighted snippet via Prism.
+--
+--   Conservative-by-design: the trigger only fires on paths under a
+--   short whitelist of top-level directories, or a small set of named
+--   root files. This keeps the parser cheap and avoids false positives
+--   on words that happen to contain a slash and a dot.
+module Filters.SourceRefs (apply, isSourcePath, forgejoSourceUrl) where
+
+import           Data.IORef           (IORef, atomicModifyIORef', newIORef, readIORef)
+import qualified Data.Map.Strict      as Map
+import           Data.Text            (Text)
+import qualified Data.Text            as T
+import           System.Directory     (doesFileExist)
+import           System.IO.Unsafe     (unsafePerformIO)
+import           Text.Pandoc.Definition
+import           Text.Pandoc.Walk     (walkM)
+
+-- | Two passes: lift Forgejo source URLs in existing Markdown links
+--   first, then wrap inline-code source paths. Both passes only add
+--   the @source-ref@ class when it is not already present, so re-runs
+--   are idempotent.
+--
+--   Runs in 'IO' because the heuristic confirms each candidate is a
+--   real on-disk file before wrapping. This rules out paths like
+--   @data/backlinks.json@ that look like source but are Hakyll build
+--   artifacts produced into @_site/@ — wrapping those would emit a
+--   link whose popup is guaranteed to 404.
+apply :: Pandoc -> IO Pandoc
+apply doc = do
+    afterLinks <- walkM classifyExistingLink doc
+    walkM wrapInlineCode afterLinks
+
+-- | Inline @`path`@ → @\<a class="source-ref" data-source-path="path"\>\<code\>path\<\/code\>\<\/a\>@.
+--   The original 'Code' node is preserved as the link's body so the
+--   inline-code chrome (mono font, background) survives unchanged.
+wrapInlineCode :: Inline -> IO Inline
+wrapInlineCode orig@(Code (cIdent, cClasses, cKvs) txt)
+    | "source-ref" `notElem` cClasses
+    , isSourcePath txt = do
+        exists <- existsCached txt
+        if exists
+            then pure $ Link
+                    ( ""
+                    , ["source-ref"]
+                    , [ ("data-source-path", txt)
+                      , ("target",           "_blank")
+                      , ("rel",              "noopener noreferrer")
+                      ]
+                    )
+                    [Code (cIdent, cClasses, cKvs) txt]
+                    (forgejoSourceUrl txt, "")
+            else pure orig
+wrapInlineCode x = pure x
+
+-- | Existing Markdown link to a Forgejo source URL on this site's git
+--   host → tagged @source-ref@ and given a @data-source-path@ pointing
+--   at the same path the popup provider expects.
+classifyExistingLink :: Inline -> IO Inline
+classifyExistingLink orig@(Link (ident, classes, kvs) ils (url, title))
+    | "source-ref" `notElem` classes
+    , Just path <- forgejoSourcePath url
+    , isSourcePath path = do
+        exists <- existsCached path
+        if exists
+            then pure $ Link
+                    ( ident
+                    , classes ++ ["source-ref"]
+                    , kvs ++ [("data-source-path", path)]
+                    )
+                    ils (url, title)
+            else pure orig
+classifyExistingLink x = pure x
+
+-- ---------------------------------------------------------------------------
+-- Heuristic
+-- ---------------------------------------------------------------------------
+
+-- | True when the text looks like a repo-relative path under one of
+--   the whitelisted directories (or is a whitelisted root file), ends
+--   in a known source extension, and contains only safe path
+--   characters. Conservative by design — the goal is no false
+--   positives on prose that incidentally contains a slash and a dot.
+isSourcePath :: Text -> Bool
+isSourcePath t = and
+    [ not (T.null t)
+    , T.all safeChar t
+    , (hasKnownPrefix t && hasKnownExt t) || isKnownRootFile t
+    ]
+  where
+    safeChar c =
+           ('a' <= c && c <= 'z')
+        || ('A' <= c && c <= 'Z')
+        || ('0' <= c && c <= '9')
+        || c == '/' || c == '.' || c == '_' || c == '-' || c == '+'
+
+hasKnownPrefix :: Text -> Bool
+hasKnownPrefix t = any (`T.isPrefixOf` t)
+    [ "build/", "static/", "templates/", "tools/"
+    , "nginx/", "data/",   "content/",   "yaml-source/"
+    ]
+
+hasKnownExt :: Text -> Bool
+hasKnownExt t =
+    let lower = T.toLower t
+    in  any (`T.isSuffixOf` lower)
+            [ ".hs", ".js", ".mjs", ".css", ".html"
+            , ".py", ".cabal", ".md", ".yaml", ".yml"
+            , ".toml", ".sh", ".bash", ".svg", ".conf"
+            , ".json", ".ini", ".tex"
+            ]
+
+isKnownRootFile :: Text -> Bool
+isKnownRootFile t = t `elem`
+    [ "Makefile"
+    , "levineuwirth.cabal"
+    , "cabal.project", "cabal.project.freeze"
+    , "pyproject.toml", "uv.lock"
+    , "WRITING.md", "HOMEPAGE.md", "PHOTOGRAPHY.md", "README.md"
+    , "LICENSE", "checklist.md"
+    ]
+
+-- ---------------------------------------------------------------------------
+-- File existence cache
+-- ---------------------------------------------------------------------------
+
+-- | Process-wide memo of @doesFileExist@ results, keyed by the same
+--   path the popup will fetch. Hakyll runs this filter once per
+--   compiled page and the same source-file references recur across
+--   many pages (e.g. @build\/Filters\/Links.hs@ in the Links page,
+--   the Colophon, several essays); the cache turns N stats into one
+--   per distinct path. The build process's working directory is the
+--   project root, so the path can be passed straight to
+--   'doesFileExist' without prefixing.
+{-# NOINLINE existsCacheRef #-}
+existsCacheRef :: IORef (Map.Map Text Bool)
+existsCacheRef = unsafePerformIO (newIORef Map.empty)
+
+existsCached :: Text -> IO Bool
+existsCached path = do
+    cache <- readIORef existsCacheRef
+    case Map.lookup path cache of
+        Just b  -> pure b
+        Nothing -> do
+            b <- doesFileExist (T.unpack path)
+            atomicModifyIORef' existsCacheRef (\m -> (Map.insert path b m, ()))
+            pure b
+
+-- ---------------------------------------------------------------------------
+-- Forgejo URL helpers
+-- ---------------------------------------------------------------------------
+
+-- | Forgejo source-viewer URL for a repo-relative path. Pinned to the
+--   @main@ branch so previews always reflect the deployed tip.
+forgejoSourceUrl :: Text -> Text
+forgejoSourceUrl path =
+    "https://git.levineuwirth.org/neuwirth/levineuwirth.org/src/branch/main/"
+    <> path
+
+-- | Inverse of 'forgejoSourceUrl': extract the repo-relative path from
+--   a Forgejo URL on this site's git host. Recognises both the
+--   @\/src\/branch\/<b>\/@ web view and the @\/raw\/branch\/<b>\/@
+--   variants. Returns 'Nothing' for any other URL.
+forgejoSourcePath :: Text -> Maybe Text
+forgejoSourcePath url = do
+    rest <- T.stripPrefix repoBase url
+    afterBranch <-
+        case T.stripPrefix "src/branch/" rest of
+            Just r  -> Just r
+            Nothing -> T.stripPrefix "raw/branch/" rest
+    let (_branch, slashAndPath) = T.breakOn "/" afterBranch
+        path                    = T.drop 1 slashAndPath
+    if T.null path then Nothing else Just path
+  where
+    repoBase = "https://git.levineuwirth.org/neuwirth/levineuwirth.org/"

build/Site.hs

@@ -197,6 +197,50 @@ rules = do
     -- Templates
     match "templates/**" $ compile templateBodyCompiler
 
+    -- ---------------------------------------------------------------------------
+    -- Source-preview corpus — raw copies of source files, served at
+    -- @/source/<path>@, fetched on hover by the popup provider in
+    -- @static/js/popups.js@ (sourceContent → Prism highlighting).
+    --
+    -- Conservative whitelist: must stay aligned with 'isSourcePath' in
+    -- @build/Filters/SourceRefs.hs@ so that every link the filter
+    -- emits has a corresponding @/source/…@ target. Files in @static/@
+    -- are also served under their normal /js/, /css/ paths via a
+    -- separate rule above; the @"source-preview"@ version lets Hakyll
+    -- compile the same identifier twice without conflict.
+    --
+    -- Anything not matched here will silently 404 on hover and the
+    -- popup will simply not appear, which is the right failure mode
+    -- if the heuristic ever wraps a path we did not mean to expose.
+    -- ---------------------------------------------------------------------------
+    let sourcePreviewable =
+                 "build/**.hs"
+            .||. "static/js/**"
+            .||. "static/css/**"
+            .||. "templates/**"
+            .||. "tools/**.sh"
+            .||. "tools/**.py"
+            .||. "nginx/**.conf"
+            .||. "data/*.json"
+            .||. "data/*.yaml"
+            .||. "data/*.md"
+            .||. "data/*.bib"
+            .||. "*.cabal"
+            .||. "cabal.project"
+            .||. "cabal.project.freeze"
+            .||. "Makefile"
+            .||. "pyproject.toml"
+            .||. "uv.lock"
+            .||. "LICENSE"
+            .||. "checklist.md"
+            .||. "WRITING.md"
+            .||. "HOMEPAGE.md"
+            .||. "PHOTOGRAPHY.md"
+            .||. "README.md"
+    match sourcePreviewable $ version "source-preview" $ do
+        route   $ customRoute (\ident -> "source/" ++ toFilePath ident)
+        compile copyFileCompiler
+
     -- Link annotations — author-defined previews for any URL
     match "data/annotations.json" $ do
         route   idRoute

content/links.md

@@ -13,7 +13,7 @@ beside each link are stamped automatically by the build's link classifier
 ## <span class="links-section-ornament" data-ornament="academic" aria-hidden="true"></span>Academic { #academic }
 
 - [Brown CS](https://cs.brown.edu/people/ugrad/lneuwirt/)
-
+- [Google Scholar](https://scholar.google.com/citations?user=9_62MFgAAAAJ&hl=en&oi=ao)
 - [ORCID](https://orcid.org/0000-0000-0000-0000)
 
 </section>
@@ -22,7 +22,7 @@ beside each link are stamped automatically by the build's link classifier
 
 ## <span class="links-section-ornament" data-ornament="artistic" aria-hidden="true"></span>Artistic { #artistic }
 
-Coming soon!
+- [YouTube](https://www.youtube.com/@levineuwirth)
 
 </section>
 
@@ -31,7 +31,6 @@ Coming soon!
 ## <span class="links-section-ornament" data-ornament="code" aria-hidden="true"></span>Code { #code }
 
 - [Forgejo](https://git.levineuwirth.org/neuwirth)
-
 - [GitHub](https://github.com/levineuwirth)
 
 </section>
@@ -41,7 +40,9 @@ Coming soon!
 ## <span class="links-section-ornament" data-ornament="miscellaneous" aria-hidden="true"></span>Miscellaneous { #miscellaneous }
 
 - [English Wikipedia](https://en.wikipedia.org/wiki/User:LudicrousSengir)
-
+- [French Wikipedia](https://fr.wikipedia.org/wiki/Utilisateur:LudicrousSengir)
+- [iNaturalist](https://inaturalist.org/people/lneuwirth)
+- [Spanish Wikipedia](https://es.wikipedia.org/wiki/User:LudicrousSengir)
 </section>
 
 <section class="links-section">

levineuwirth.cabal

@@ -39,6 +39,7 @@ executable site
         Filters.Transclusion
         Filters.EmbedPdf
         Filters.Links
+        Filters.SourceRefs
         Filters.Math
         Filters.Code
         Filters.Images

static/css/popups.css

@@ -231,6 +231,96 @@
     object-position: top left;
 }
 
+/* ============================================================
+   SOURCE-FILE PREVIEW POPUP
+   Shown on hover for inline `path/to/file` references and for
+   Markdown links to the Forgejo source viewer (see
+   build/Filters/SourceRefs.hs). The body is fetched from
+   /source/<path> and Prism-highlighted client-side.
+   ============================================================ */
+
+.link-popup:has(.popup-source-code) {
+    max-width: 560px;
+    padding: 0;
+    overflow: hidden;
+}
+
+.popup-source-code {
+    display: block;
+}
+
+/* Header strip naming the file. Doubles as a visual seam between the
+   chrome (border, padding) and the code body below. */
+.popup-source-path {
+    padding: 0.45rem 0.65rem 0.4rem;
+    border-bottom: 1px solid var(--border);
+    font-family: var(--font-mono);
+    font-size: 0.65rem;
+    color: var(--text-faint);
+    word-break: break-all;
+    background: var(--bg);
+}
+
+.popup-source-pre {
+    margin: 0;
+    padding: 0.55rem 0.65rem;
+    max-height: 360px;
+    overflow: auto;
+    background: var(--bg);
+    font-family: var(--font-mono);
+    font-size: 0.7rem;
+    line-height: 1.5;
+    color: var(--text);
+    white-space: pre;
+    border: none;
+    border-radius: 0;
+}
+
+.popup-source-pre code {
+    background: transparent;
+    padding: 0;
+    border: none;
+    font-family: inherit;
+    font-size: inherit;
+    color: inherit;
+    white-space: pre;
+}
+
+/* "N more lines · view full file →" — visually parallel to the path
+   header strip; together they bracket the code body. */
+.popup-source-truncated {
+    padding: 0.4rem 0.65rem;
+    border-top: 1px solid var(--border);
+    font-size: 0.65rem;
+    font-variant-caps: all-small-caps;
+    letter-spacing: 0.07em;
+    color: var(--text-faint);
+    background: var(--bg);
+}
+
+/* Inline source-ref link styling: keep the inline-code chrome of the
+   wrapped <code> intact and resist the link-classifier's external/
+   internal stamp (Filters.Links explicitly skips us). The hover hint
+   is a faint dotted underline — same convention as date-hover and
+   epistemic-term cues. */
+a.source-ref {
+    color: inherit;
+    text-decoration: none;
+}
+
+a.source-ref:hover {
+    text-decoration-line: underline;
+    text-decoration-style: dotted;
+    text-decoration-color: var(--border-muted);
+    text-underline-offset: 0.2em;
+}
+
+a.source-ref code {
+    /* The underlying inline-code styling is inherited from typography.css;
+       this rule exists only to ensure the link wrapper does not fight it. */
+    color: inherit;
+}
+
 /* PGP signature popup */
 .popup-sig pre {
     margin: 0;

static/js/popups.js

@@ -110,6 +110,15 @@
             bind(el, internalContent);
         });
 
+        /* Source-file references — wrapped at build time by
+           build/Filters/SourceRefs.hs around inline `path` and Forgejo
+           links. Bind before the generic external-link loop so the
+           idempotent guard in bind() prevents the Forgejo provider
+           from also claiming these. */
+        root.querySelectorAll('a.source-ref[data-source-path]').forEach(function (el) {
+            bind(el, sourceContent);
+        });
+
         /* PDF links — rewritten to viewer URL by Links.hs; thumbnail on hover */
         root.querySelectorAll('a.pdf-link[data-pdf-src]').forEach(function (el) {
             bind(el, pdfContent);
@@ -785,6 +794,109 @@
             .catch(function () { return null; });
     }
 
+    /* Source-file preview — fetches /source/<path> (a same-origin copy
+       emitted by the source-preview Hakyll rule), runs Prism on the
+       first chunk of lines, and returns a DocumentFragment so the popup
+       receives ready-highlighted DOM rather than re-parsing innerHTML.
+
+       The raw response is cached; rendering is repeated per hover so
+       a cached entry never gets re-parented (a Node can only live in
+       one place at a time). */
+    function sourceContent(target) {
+        var path = target.dataset.sourcePath;
+        if (!path) return Promise.resolve(null);
+        var fetchUrl = '/source/' + path;
+
+        var cached = cache[fetchUrl];
+        var pending = (cached !== undefined)
+            ? Promise.resolve(cached)
+            : fetch(fetchUrl, { credentials: 'same-origin' })
+                .then(function (r) { return r.ok ? r.text() : null; })
+                .then(function (text) { cache[fetchUrl] = text; return text; })
+                .catch(function () { return null; });
+
+        return pending.then(function (text) {
+            if (text == null) return null;
+            return renderSourcePopup(path, text);
+        });
+    }
+
+    /* Build the popup body for sourceContent. Truncates to MAX_LINES
+       so a 2,000-line file doesn't blow the popup height; the link's
+       href still points at the Forgejo full-file viewer for readers
+       who want more. */
+    function renderSourcePopup(path, text) {
+        var MAX_LINES = 80;
+        var lines     = text.split('\n');
+        var truncated = lines.length > MAX_LINES;
+        var preview   = lines.slice(0, MAX_LINES).join('\n');
+        var lang      = languageFromPath(path);
+
+        var wrap = document.createElement('div');
+        wrap.className = 'popup-source-code';
+
+        var label = document.createElement('div');
+        label.className = 'popup-source-path';
+        label.textContent = path;
+        wrap.appendChild(label);
+
+        var pre  = document.createElement('pre');
+        pre.className = lang ? 'popup-source-pre language-' + lang : 'popup-source-pre';
+        var code = document.createElement('code');
+        if (lang) code.className = 'language-' + lang;
+        code.textContent = preview;
+        pre.appendChild(code);
+        wrap.appendChild(pre);
+
+        /* Prism is loaded with `defer` from the page template; by the
+           time a hover delay fires it is reliably available. Guard
+           anyway so a missing component (e.g. an unrecognised lang)
+           degrades to plain monospace rather than throwing. */
+        if (lang && window.Prism && Prism.languages && Prism.languages[lang]) {
+            try { Prism.highlightElement(code); } catch (_) { /* keep plain */ }
+        }
+
+        if (truncated) {
+            var more = document.createElement('div');
+            more.className = 'popup-source-truncated';
+            var n = lines.length - MAX_LINES;
+            more.textContent =
+                n + ' more line' + (n === 1 ? '' : 's')
+                + ' · view full file →';
+            wrap.appendChild(more);
+        }
+
+        return wrap;
+    }
+
+    /* Map a path's extension (or basename, for Makefile) onto the set
+       of Prism languages bundled in /js/prism.min.js: bash, haskell,
+       javascript, css, markup, yaml, python, makefile. Returns null
+       when no mapping applies; the caller falls back to plain text. */
+    function languageFromPath(path) {
+        var basename = path.split('/').pop();
+        if (basename === 'Makefile') return 'makefile';
+        var m = path.match(/\.([a-z0-9]+)$/i);
+        if (!m) return null;
+        switch (m[1].toLowerCase()) {
+            case 'hs':
+            case 'cabal':   return 'haskell';
+            case 'js':
+            case 'mjs':     return 'javascript';
+            case 'css':     return 'css';
+            case 'html':
+            case 'svg':     return 'markup';
+            case 'py':      return 'python';
+            case 'sh':
+            case 'bash':
+            case 'conf':    return 'bash';
+            case 'yaml':
+            case 'yml':     return 'yaml';
+            case 'md':      return 'markup';
+            default:        return null;
+        }
+    }
+
     /* PGP signature — fetch the .sig file and display ASCII armor */
     function sigContent(target) {
         var href = target.getAttribute('href');