Add support for GitHub-style alerts

md.lua

@@ -80,7 +80,7 @@ end
 
 local function externalLinkEscape(str, t)
     local nomatches = true
-    for m1, m2, m3 in gmatch(str, '(.*)%[(.*)%](.*)') do
+    for m1, m2, m3 in gmatch(str, '(.*)%[%w(.*)%](.*)') do
         if nomatches then t[#t + 1] = match(m1, '^(.-)!?$'); nomatches = false end
         if byte(m1, #m1) == byte '!' then
             t[#t + 1] = {type = 'img', attributes = {alt = m2}}
@@ -197,10 +197,12 @@ local PATTERN_RULE1 = "^%s?%s?%s?(-%s*-%s*-[%s-]*)$"
 local PATTERN_RULE2 = "^%s?%s?%s?(*%s**%s**[%s*]*)$"
 local PATTERN_RULE3 = "^%s?%s?%s?(_%s*_%s*_[%s_]*)$"
 local PATTERN_CODEBLOCK = "^%s*%`%`%`(.*)"
+local PATTERN_BLOCKALERT = "^%s*> %[!(.*)%]"
 local PATTERN_BLOCKQUOTE = "^%s*> (.*)$"
 local PATTERN_ULIST = "^%s*[%*%-] (.+)$"
 local PATTERN_OLIST = "^%s*%d+%. (.+)$"
 local PATTERN_LINKDEF = "^%s*%[(.*)%]%s*%:%s*(.*)"
+local PATTERN_TABLE = "^%s*|(.*)|%s*$"
 
 -- List of patterns
 local PATTERNS = {
@@ -211,10 +213,12 @@ local PATTERNS = {
     PATTERN_RULE2,
     PATTERN_RULE3,
     PATTERN_CODEBLOCK,
+    PATTERN_BLOCKALERT,
     PATTERN_BLOCKQUOTE,
     PATTERN_ULIST,
     PATTERN_OLIST,
-    PATTERN_LINKDEF
+    PATTERN_LINKDEF,
+    PATTERN_TABLE
 }
 
 local function isSpecialLine(line)
@@ -349,6 +353,101 @@ local function readBlockQuote(pop, peek, tree, links)
     end
 end
 
+local function readBlockAlert(pop, peek, tree, links)
+    local line = peek()
+    local type_alert, txt = match(line, PATTERN_BLOCKALERT)
+    if type_alert then
+        local ba = {
+            type = "div",
+            attributes = { class = format('markdown-alert markdown-alert-%s', lower(type_alert)) }
+        }
+
+        tree[#tree + 1] = ba
+        if match(pop(), PATTERN_BLOCKQUOTE) then
+            local bqh = {
+                type = "p",
+                attributes = { class = 'markdown-alert-icon' }
+            }
+            ba[#ba + 1] = bqh
+
+            local bqv = readFragment(pop, peek, links, function(l)
+                local tp = isSpecialLine(l)
+                return tp and tp ~= PATTERN_BLOCKQUOTE
+            end)
+
+            ba[#ba + 1] = bqv
+            ba[#ba + 1] = '\r\n'
+        end
+
+        return peek()
+    end
+end
+
+local function readTable(pop, peek, tree, links)
+    local line = peek()
+    local row1, txt = match(line, PATTERN_TABLE)
+    if row1 then
+        local t = {
+            type = "table",
+            attributes = { class = 'table table-markdown' }
+        }
+
+        tree[#tree + 1] = t
+        local thead = { type = "thead" }
+        t[#t + 1] = thead
+        local tbody = { type = "tbody" }
+        t[#t + 1] = tbody
+
+        local thead_ok = false
+        while true do
+            line = pop()
+            if not line then break end
+            -- add header
+            if thead_ok == false then
+                thead_ok = true
+                if match(line, "^%s*|%s*%-%-%-") then
+                    local tr = { type = "tr" }
+                    thead[#thead + 1] = tr
+                    for col in row1:gmatch("[^|]+") do
+                        local th = { col, type = "th" }
+                        tr[#tr + 1] = th
+                    end
+                    line = pop()
+                else
+                    local tr = {
+                        type = "tr",
+                        attributes = { class = '' }
+                    }
+                    tbody[#tbody + 1] = tr
+                    for col in row1:gmatch("[^|]+") do
+                        local td = { col, type = "td" }
+                        tr[#tr + 1] = td
+                    end
+                end
+            end
+
+            local row, txt = match(line, PATTERN_TABLE)
+            if row then
+                local tr = {
+                    type = "tr",
+                    attributes = { class = '' }
+                }
+                tbody[#tbody + 1] = tr
+
+                for col in row:gmatch("[^|]+") do
+                    local td = { col, type = "td" }
+                    tr[#tr + 1] = td
+                end
+
+            else
+                break
+            end
+        end
+
+        return peek()
+    end
+end
+
 local function readList(pop, peek, tree, links, expectedIndent)
     if not peek() then return end
     if expectedIndent and getIndentLevel(peek()) ~= expectedIndent then return end
@@ -398,9 +497,13 @@ function readLineStream(stream, tree, links)
     tree = tree or {}
     links = links or {}
     while peek() do
-        if not readBlockQuote(pop, peek, tree, links) then
-            if not readList(pop, peek, tree, links) then
-                readSimple(pop, peek, tree, links)
+        if not readBlockAlert(pop, peek, tree, links) then
+            if not readBlockQuote(pop, peek, tree, links) then
+                if not readTable(pop, peek, tree, links) then
+                    if not readList(pop, peek, tree, links) then
+                        readSimple(pop, peek, tree, links)
+                    end
+                end
             end
         end
     end