chore: create styling module

styling.lua

@@ -0,0 +1,140 @@
+local module = {}
+local function styleLists(s)
+    local lines = {}
+    for line in (s .. "\n"):gmatch("([^\n]*)\n") do
+        table.insert(lines, line)
+    end
+
+    local result = {}
+    local inUl = false
+    local inOl = false
+
+    for _, line in ipairs(lines) do
+        local ulItem = line:match("^[%-%*%+]%s+(.*)")
+        local olItem = line:match("^%d+%.%s+(.*)")
+
+        if ulItem then
+            if inOl then
+                table.insert(result, "</ol>")
+                inOl = false
+            end
+            if not inUl then
+                table.insert(result, "<ul>")
+                inUl = true
+            end
+            table.insert(result, "<li>" .. ulItem .. "</li>") -- ulItem!
+        elseif olItem then
+            if inUl then
+                table.insert(result, "</ul>")
+                inUl = false
+            end
+            if not inOl then
+                table.insert(result, "<ol>")
+                inOl = true
+            end
+            table.insert(result, "<li>" .. olItem .. "</li>")
+        else
+            if inUl then
+                table.insert(result, "</ul>")
+                inUl = false
+            end
+            if inOl then
+                table.insert(result, "</ol>")
+                inOl = false
+            end
+            table.insert(result, line)
+        end
+    end
+
+    if inUl then
+        table.insert(result, "</ul>")
+    end
+    if inOl then
+        table.insert(result, "</ol>")
+    end
+
+    return table.concat(result, "\n")
+end
+local function styleParagraph(s)
+    local lines = {}
+    for line in (s .. "\n"):gmatch("([^\n]*)\n") do
+        table.insert(lines, line)
+    end
+
+    local result = {}
+    local pLines = {}
+
+    local function flushP()
+        if #pLines > 0 then
+            table.insert(result, "<p>" .. table.concat(pLines, "\n") .. "</p>")
+            pLines = {}
+        end
+    end
+
+    for _, line in ipairs(lines) do
+        local isBlock = line:match("^<") or line:match("^#")
+        local isEmpty = line:match("^%s*$")
+
+        if isBlock or isEmpty then
+            flushP()
+            table.insert(result, line)
+        else
+            table.insert(pLines, line)
+        end
+    end
+    flushP()
+
+    return table.concat(result, "\n")
+end
+function module.transform(s)
+    -- blockquote
+    local lines = {}
+    for line in (s .. "\n"):gmatch("([^\n]*)\n?") do
+        local nline = line:gsub("^>%s*(.*)", "<blockquote>%1</blockquote>")
+        table.insert(lines, nline)
+    end
+    s = table.concat(lines, "\n")
+    -- lists
+    s = styleLists(s)
+    -- paragraph
+    s = styleParagraph(s)
+    s = s:gsub("<p></p>", "")
+    -- line breaks
+    s = s:gsub("\r?\n", "<br>")
+    -- remove <br> tags around block elements
+    local blockTags = { "ul", "ol", "li", "blockquote", "p", "h1", "h2", "h3", "h4", "h5", "h6", "hr" }
+    for _, tag in ipairs(blockTags) do
+        s = s:gsub("(</" .. tag .. ">)<br>", "%1")
+        s = s:gsub("<br>(</" .. tag .. ">)", "%1")
+        s = s:gsub("(<" .. tag .. ">)<br>", "%1")
+        s = s:gsub("<br>(<" .. tag .. ">)", "%1")
+    end
+    -- self-closing hr
+    s = s:gsub("(<hr>)<br>", "%1")
+    s = s:gsub("<br>(<hr>)", "%1")
+    -- headers
+    s = s:gsub("######%s*(.-)%s*<br>", "<h6>%1</h6>")
+    s = s:gsub("#####%s*(.-)%s*<br>", "<h5>%1</h5>")
+    s = s:gsub("####%s*(.-)%s*<br>", "<h4>%1</h4>")
+    s = s:gsub("###%s*(.-)%s*<br>", "<h3>%1</h3>")
+    s = s:gsub("##%s*(.-)%s*<br>", "<h2>%1</h2>")
+    s = s:gsub("#%s*(.-)%s*<br>", "<h1>%1</h1>")
+    -- TODO: h1 and h2 using == and --
+    -- bold and italic text
+    s = s:gsub("%*%*(.-)%*%*", "<b>%1</b>")
+    s = s:gsub("%*(.-)%*", "<i>%1</i>")
+    s = s:gsub("%_%_(.-)%_%_", "<b>%1</b>")
+    s = s:gsub("%_(.-)%_", "<i>%1</i>")
+    -- images
+    s = s:gsub("!%[(.-)%]%((.-)%)", '<img src="%2" alt="%1"></img>')
+    -- links
+    s = s:gsub("%[(.-)%]%((.-)%)", '<a href="%2">%1</a>')
+    -- code
+    s = s:gsub("`(.-)`", "<code>%1</code>")
+    -- horizontal rule
+    s = s:gsub("%-%-%-", "<hr>")
+
+    return s
+end
+
+return module