1 files changed, 117 insertions, 0 deletions
diff --git a/tex/context/base/util-tpl.lua b/tex/context/base/util-tpl.lua
new file mode 100644
index 000000000..4cde1863b
--- /dev/null
+++ b/tex/context/base/util-tpl.lua
@@ -0,0 +1,117 @@
+if not modules then modules = { } end modules ['util-tpl'] = {
+    version   = 1.001,
+    comment   = "companion to luat-lib.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- This is experimental code. Coming from dos and windows, I've always used %whatever%
+-- as template variables so let's stick to it. After all, it's easy to parse and stands
+-- out well. A double %% is turned into a regular %.
+
+utilities.templates = utilities.templates or { }
+local templates     = utilities.templates
+
+local trace_template  = false  trackers.register("templates.trace",function(v) trace_template = v end)
+local report_template = logs.reporter("template")
+
+local format = string.format
+local P, C, Cs, Carg, lpegmatch = lpeg.P, lpeg.C, lpeg.Cs, lpeg.Carg, lpeg.match
+
+-- todo: make installable template.new
+
+local replacer
+
+local function replacekey(k,t,recursive)
+    local v = t[k]
+    if not v then
+        if trace_template then
+            report_template("unknown key %q",k)
+        end
+        return ""
+    else
+        if trace_template then
+            report_template("setting key %q to value %q",k,v)
+        end
+        if recursive then
+            return lpegmatch(replacer,v,1,t)
+        else
+            return v
+        end
+    end
+end
+
+local sqlescape = lpeg.replacer {
+    { "'",    "''"   },
+    { "\\",   "\\\\" },
+    { "\r\n", "\\n"  },
+    { "\r",   "\\n"  },
+ -- { "\t",   "\\t"  },
+}
+
+local escapers = {
+    lua = function(s)
+        return format("%q",s)
+    end,
+    sql = function(s)
+        return lpegmatch(sqlescape,s)
+    end,
+}
+
+local function replacekeyunquoted(s,t,how,recurse) -- ".. \" "
+    local escaper = how and escapers[how] or escapers.lua
+    return escaper(replacekey(s,t,recurse))
+end
+
+local single      = P("%")  -- test %test% test   : resolves test
+local double      = P("%%") -- test 10%% test     : %% becomes %
+local lquoted     = P("%[") -- test %[test]" test : resolves test with escaped "'s
+local rquoted     = P("]%") --
+
+local escape      = double  / '%%'
+local nosingle    = single  / ''
+local nodouble    = double  / ''
+local nolquoted   = lquoted / ''
+local norquoted   = rquoted / ''
+
+local key         = nosingle * (C((1-nosingle)^1 * Carg(1) * Carg(2) * Carg(3))/replacekey) * nosingle
+local unquoted    = nolquoted * ((C((1 - norquoted)^1) * Carg(1) * Carg(2) * Carg(3))/replacekeyunquoted) * norquoted
+local any         = P(1)
+
+      replacer    = Cs((unquoted + escape + key + any)^0)
+
+local function replace(str,mapping,how,recurse)
+    if mapping then
+        return lpegmatch(replacer,str,1,mapping,how or "lua",recurse or false) or str
+    else
+        return str
+    end
+end
+
+-- print(replace("test '%[x]%' test",{ x = [[a 'x'  a]] }))
+-- print(replace("test '%[x]%' test",{ x = [[a 'x'  a]] },'sql'))
+
+templates.replace = replace
+
+function templates.load(filename,mapping,how,recurse)
+    local data = io.loaddata(filename) or ""
+    if mapping and next(mapping) then
+        return replace(data,mapping,how,recurse)
+    else
+        return data
+    end
+end
+
+function templates.resolve(t,mapping,how,recurse)
+    if not mapping then
+        mapping = t
+    end
+    for k, v in next, t do
+        t[k] = replace(v,mapping,how,recurse)
+    end
+    return t
+end
+
+-- inspect(utilities.templates.replace("test %one% test", { one = "%two%", two = "two" }))
+-- inspect(utilities.templates.resolve({ one = "%two%", two = "two", three = "%three%" }))