feat(presets): add asciidoctor preset

Adds an asciidoctor preset for AsciiDoc → HTML compilation with SSE
live-reload. Includes a parse_asciidoctor error parser handling the
"asciidoctor: SEVERITY: file: line N: message" format for both
ERROR and WARNING diagnostics.

doc/preview.nvim.txt

@@ -161,6 +161,7 @@ Import them from `preview.presets`:
   `presets.tectonic`           tectonic → PDF (Rust-based LaTeX engine)
   `presets.markdown`           pandoc → HTML (standalone, embedded)
   `presets.github`             pandoc → HTML (GitHub-styled, `-f gfm` input)
+  `presets.asciidoctor`        asciidoctor → HTML (AsciiDoc with SSE reload)
 
 Enable presets with `preset_name = true`:
 >lua

lua/preview/presets.lua

@@ -93,6 +93,29 @@ local function parse_pandoc(output)
   return diagnostics
 end
 
+---@param output string
+---@return preview.Diagnostic[]
+local function parse_asciidoctor(output)
+  local diagnostics = {}
+  for line in output:gmatch('[^\r\n]+') do
+    local severity, _, lnum, msg =
+      line:match('^asciidoctor: (%u+): (.+): line (%d+): (.+)$')
+    if lnum then
+      local sev = vim.diagnostic.severity.ERROR
+      if severity == 'WARNING' then
+        sev = vim.diagnostic.severity.WARN
+      end
+      table.insert(diagnostics, {
+        lnum = tonumber(lnum) - 1,
+        col = 0,
+        message = msg,
+        severity = sev,
+      })
+    end
+  end
+  return diagnostics
+end
+
 ---@type preview.ProviderConfig
 M.typst = {
   ft = 'typst',
@@ -219,4 +242,24 @@ M.github = {
   reload = true,
 }
 
+---@type preview.ProviderConfig
+M.asciidoctor = {
+  ft = 'asciidoc',
+  cmd = { 'asciidoctor' },
+  args = function(ctx)
+    return { ctx.file, '-o', ctx.output }
+  end,
+  output = function(ctx)
+    return (ctx.file:gsub('%.adoc$', '.html'))
+  end,
+  error_parser = function(output)
+    return parse_asciidoctor(output)
+  end,
+  clean = function(ctx)
+    return { 'rm', '-f', (ctx.file:gsub('%.adoc$', '.html')) }
+  end,
+  open = true,
+  reload = true,
+}
+
 return M

spec/presets_spec.lua

@@ -447,4 +447,75 @@ describe('presets', function()
       assert.are.same({}, diagnostics)
     end)
   end)
+
+  describe('asciidoctor', function()
+    local adoc_ctx = {
+      bufnr = 1,
+      file = '/tmp/document.adoc',
+      root = '/tmp',
+      ft = 'asciidoc',
+      output = '/tmp/document.html',
+    }
+
+    it('has ft', function()
+      assert.are.equal('asciidoc', presets.asciidoctor.ft)
+    end)
+
+    it('has cmd', function()
+      assert.are.same({ 'asciidoctor' }, presets.asciidoctor.cmd)
+    end)
+
+    it('returns args with file and output', function()
+      assert.are.same(
+        { '/tmp/document.adoc', '-o', '/tmp/document.html' },
+        presets.asciidoctor.args(adoc_ctx)
+      )
+    end)
+
+    it('returns html output path', function()
+      assert.are.equal('/tmp/document.html', presets.asciidoctor.output(adoc_ctx))
+    end)
+
+    it('returns clean command', function()
+      assert.are.same(
+        { 'rm', '-f', '/tmp/document.html' },
+        presets.asciidoctor.clean(adoc_ctx)
+      )
+    end)
+
+    it('has open enabled', function()
+      assert.is_true(presets.asciidoctor.open)
+    end)
+
+    it('has reload enabled for SSE', function()
+      assert.is_true(presets.asciidoctor.reload)
+    end)
+
+    it('parses error messages', function()
+      local output =
+        'asciidoctor: ERROR: document.adoc: line 8: invalid part, must have at least one section'
+      local diagnostics = presets.asciidoctor.error_parser(output, adoc_ctx)
+      assert.are.equal(1, #diagnostics)
+      assert.are.equal(7, diagnostics[1].lnum)
+      assert.are.equal(0, diagnostics[1].col)
+      assert.are.equal(
+        'invalid part, must have at least one section',
+        diagnostics[1].message
+      )
+      assert.are.equal(vim.diagnostic.severity.ERROR, diagnostics[1].severity)
+    end)
+
+    it('parses warning messages', function()
+      local output =
+        'asciidoctor: WARNING: document.adoc: line 52: section title out of sequence'
+      local diagnostics = presets.asciidoctor.error_parser(output, adoc_ctx)
+      assert.are.equal(1, #diagnostics)
+      assert.are.equal(51, diagnostics[1].lnum)
+      assert.are.equal(vim.diagnostic.severity.WARN, diagnostics[1].severity)
+    end)
+
+    it('returns empty table for clean output', function()
+      assert.are.same({}, presets.asciidoctor.error_parser('', adoc_ctx))
+    end)
+  end)
 end)