initial

elua.moon

@@ -0,0 +1,123 @@
+
+moon = require "moon"
+import insert, concat from table
+
+escape_pattern = do
+  punct = "[%^$()%.%[%]*+%-?%%]"
+  (str) -> (str\gsub punct, (p) -> "%"..p)
+
+class Parser
+  open_tag: "<%"
+  close_tag: "%>"
+  modifiers: "^[=-]"
+
+  next_tag: =>
+    start, stop = @str\find @open_tag, @pos, true
+
+    -- no more tags, all done
+    unless start
+      @push_raw @pos, #@str
+      return false
+
+    -- add text before
+    unless start == @pos
+      @push_raw @pos, start - 1
+
+    @pos = stop + 1
+    modifier = if @str\match @modifiers, @pos
+      with @str\sub @pos, @pos
+        @pos += 1
+
+    -- TODO: find the next tag or string, whichever is closer
+    start, stop = @str\find @close_tag, @pos, true
+    kind = modifier == "=" and "interplate" or "code"
+    @push_code kind, @pos, start - 1
+
+    @pos = stop + 1
+    true
+
+  -- closest_string: ->
+  --   start = @str\find "[=*["
+
+  push_raw: (start, stop) =>
+    insert @chunks, @str\sub start, stop
+
+  push_code: (kind, start, stop) =>
+    insert @chunks, {
+      kind, @str\sub start, stop
+    }
+
+  parse: (@str) =>
+    assert type(@str) == "string"
+    @pos = 1
+    @chunks = {}
+
+    while @next_tag!
+      nil
+
+    @compile!
+
+  -- generates the code of the template
+  compile: =>
+    -- moon.p @chunks
+    -- todo: find a no-conflict name for buffer
+    buffer = {
+      "local _b, _b_i, _tostring = {}, 0, tostring"
+    }
+    buffer_i = #buffer
+
+    push = (str) ->
+      buffer_i += 1
+      buffer[buffer_i] = str
+
+    for chunk in *@chunks
+      t = type chunk
+      t = chunk[1] if t == "table"
+      switch t
+        when "string"
+          push "_b_i = _b_i + 1"
+          push "_b[_b_i] = #{("%q")\format(chunk)}"
+        when "code"
+          push chunk[2]
+        when "interplate"
+          assign = "_b[_b_i] = _tostring(#{chunk[2]})"
+
+          -- validate syntax
+          unless loadstring assign
+            error "failed to parse: #{chunk[2]}"
+
+          push "_b_i = _b_i + 1"
+          push assign
+        else
+          error "unknown type #{t}"
+
+    push "return table.concat(_b)"
+    concat buffer, "\n"
+
+p = Parser!
+code = p\parse [[
+  This is my message to <%= "you" %>
+  This is my message to <%= 4 %>
+  <% if things then %>
+    I love things
+  <% end %>
+
+  <% for i=1,10 do%>
+    hello <%= i %>
+  <% end %>
+
+  message: <%= visitor %>
+
+  This is my message to <%= "y%>u" %>
+
+]]
+
+print code
+-- fn = assert loadstring code
+-- setfenv fn, setmetatable {
+--   visitor: "HELLO VISITOR"
+--   things: true
+-- }, __index: _G
+-- 
+-- print fn!
+