1 files changed, 127 insertions, 0 deletions
diff --git a/Tools/LuaMacro/tests/cskin.lua b/Tools/LuaMacro/tests/cskin.lua
new file mode 100644
index 0000000..d77f7f9
--- /dev/null
+++ b/Tools/LuaMacro/tests/cskin.lua
@@ -0,0 +1,127 @@
+-- cskin.lua
+local M = require 'macro'
+
+M.define_tokens{'&&','||','!=','{|'}
+
+M.define '&& and'
+M.define '|| or'
+M.define '!= ~='
+M.define '! not'
+
+local push,pop = table.insert,table.remove
+local bstack = {}
+local btop = {}
+
+local function push_brace_stack (newv)
+    newv = newv or {}
+    newv.lev = 0
+    push(bstack,btop)
+    btop = newv
+end
+
+local disabled = false
+
+-- skinning can be temporarily disabled; this macro re-enables skinning
+M.define('_SKIN_',function() disabled = false end)
+
+local function block_statement (word,end_handler)
+    return function(get,put)
+        if disabled then return end
+        get:expecting '('
+        local stuff = get:upto ')'
+        get:expecting '{'
+        push_brace_stack {handler = end_handler}
+        return put:space():tokens(stuff):space():keyword(word)
+    end
+end
+
+local function endif_handler (get,put)
+    local t,v = get:next()
+    if t == 'keyword' and v == 'else' then
+        local nt,nv = get:next()
+        if nt == 'keyword' and nv == 'if' then
+            return put:keyword 'elseif'
+        else
+            M.assert(nt == '{')
+        end
+        push_brace_stack() -- opening else block
+        return put:keyword 'else'
+    else
+        return put:keyword 'end' (t,v)
+    end
+end
+
+M.keyword_handler ('for',block_statement 'do')
+M.keyword_handler ('while',block_statement 'do')
+M.keyword_handler ('if',block_statement ('then',endif_handler))
+M.keyword_handler ('elseif',block_statement ('then',endif_handler))
+
+M.define('{',function()
+    if btop.lev then
+        btop.lev = btop.lev + 1
+    end
+    return nil,true --> pass-through macro
+end)
+
+M.define('}',function(get,put)
+    if btop.lev == 0 then
+        local res
+        if btop.handler then res = btop.handler(get,put) end
+        if not res then res = put:space():keyword'end' end
+        btop = pop(bstack)
+        return res
+    else
+        btop.lev = btop.lev - 1
+        return nil,true --> pass-through macro
+    end
+end)
+
+-- def for function is a little easier; it's a plain macro,
+-- and we deliberately don't want to get rid of the parens.
+M.define('def',function(get,put)
+    local stuff = get:list('{','')
+    put:keyword('function')
+    if btop.classname then put:iden(btop.classname) '.' end
+    push_brace_stack()
+    return put:list(stuff)
+end)
+
+----- OOP support ------
+M.define('class',function(get,put)
+    local name,t,v = get:iden(),get:next()
+    local base = ''
+    if t == ':' then base = get:iden(); t = get:next() end
+    M.assert(t == '{','expecting {')
+    push_brace_stack {classname = name}
+    return 'do '..name..' = class_('..base..')'
+end)
+
+class_ = require 'macro.lib.class'
+
+---- making an existing macro play nicely with the C skin ---
+require 'macro.forall'
+
+local fun = M.get_macro_value 'forall'
+M.define('forall',function (get,put)
+    get:expecting '('
+    local stuff = get:upto ')'
+    get:expecting'{'
+    stuff:space():keyword 'do'
+    stuff = fun(get.from_tl(stuff),put)
+    -- let the unskinned Lua pass through with _SKIN_ to re-enable skinning
+    disabled = true
+    stuff:iden '_SKIN_':space()
+    push_brace_stack()
+    return stuff
+end)
+
+-- often easier to express the macro in a skinned form
+M.define('{|',function(get,put)
+    local expr = tostring(get:upto '|')
+    local select = tostring(get:upto '}')
+    return ('(def(){local r={}; forall(%s) {r[#r+1]=%s} return r})()'):format(select,expr)
+end)
+
+
+
+