Updated with some modernity.

.gitignore

@@ -4,5 +4,6 @@
 *.orig
 npm-debug.log
 node_modules/*
-lib/
 tmp/
+src/*.js
+lib/*.js

Makefile

@@ -1,21 +1,39 @@
-.PHONY: lib test
+.PHONY: lib test library docs
 
-lib_sources:= $(wildcard src/*.coffee)
-lib_objects:= $(subst src/, lib/, $(lib_sources:%.coffee=%.js))
+COFFEE= ./node_modules/.bin/coffee
+PEGJS= ./node_modules/.bin/pegjs
+DOCCO= ./node_modules/.bin/docco
+MOCHA= ./node_modules/.bin/mocha
+
+cof_sources:= $(wildcard src/*.coffee)
+cof_objects:= $(subst src/, lib/, $(cof_sources:%.coffee=%.js)) 
+
+peg_sources:= $(wildcard src/*.peg)
+peg_objects:= $(subst src/, lib/, $(peg_sources:%.peg=%.js)) 
+
+library: $(cof_objects) $(peg_objects)
 
 default: build
 
-build: $(lib_objects) lib/tokenizer.js
+build: $(lib_objects) 
 
 lib:
 	mkdir -p lib
 
-lib/tumble.js: lib src/tumble.peg
-	./node_modules/.bin/pegjs src/tumble.peg lib/tumble.js
-
-$(lib_objects): $(lib_sources)
+$(cof_objects): $(cof_sources)
 	@mkdir -p $(@D)
-	coffee -o $(@D) -c $<
+	$(foreach source, $(cof_sources), $(COFFEE) -o $(@D) -c $(source); )
+
+$(peg_objects): $(peg_sources)
+	@mkdir -p $(@D)
+	$(PEGJS) $< $@
+
+docs:
+	$(DOCCO) $(cof_sources)
+
+echo:
+	echo $(cof_sources)
+	echo $(cof_objects)
 
 test: test/[0-9]*_mocha.coffee lib/tumble.js lib/parser.js
 	./node_modules/.bin/mocha -R tap -C --compilers coffee:coffee-script -u tdd $<

README.md

@@ -36,10 +36,13 @@ a string or a number.
 ### If
 
 An "if:<name>" section can contain other objects, but the entirety of
-the section is only rendered if the current context scope contains the
-current name, and the value associated with that name is "true" in a
-boolean context.  You might use to show someone's name, if the name
-field is populated, and show nothing if it isn't.
+the section is only rendered if the current context scope, and *only*
+the current context scope, contains the current name, and the value
+associated with that name is "true" in a boolean context.  You might
+use to show someone's name, if the name field is populated, and show
+nothing if it isn't.  This is useful for detecting if the current
+context has a field, but you don't want previous contexts' synonyms
+showing up.
 
 If your datasource returns:
 
@@ -49,6 +52,12 @@ Then your template would use:
 
     {if:name}Hello {name}!{/if:name}
 
+### When
+
+A "when:<name>" section is the same as the "if", but it will render if
+the current context scope, and any previous context scope on the
+stack, contains the current name.
+
 ### Block
 
 A "block:<name>" section can contain other objects, but the entirety

bin/activate

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+# /bin comes before /node_modules/.bin because sometimes I want to
+# override the behaviors provided.
+
+PROJECT_ROOT=`pwd`
+PATH="$PROJECT_ROOT/bin:$PROJECT_ROOT/node_modules/.bin:$PATH"
+export PATH

bin/devserver

@@ -0,0 +1,16 @@
+#!/usr/bin/env coffee
+
+staticserver = require('node-static')
+files = new(staticserver.Server)('./dist')
+
+require('http').createServer((request, response) ->
+    request.addListener 'end', ->
+        files.serve request, response, (err, res) ->
+            if (err)
+                console.error("> Error serving " + request.url + " - " + err.message)
+                response.writeHead(err.status, err.headers)
+                response.end()
+            else
+                console.log("> " + request.url + " - " + res.message)
+).listen(8081)
+console.log("> node-static is listening on http://127.0.0.1:8081")

package.json

@@ -1,7 +1,7 @@
 {
-    "name": "Tumble",
-    "description": "Trivial reimplementation of Tumbler template parser",
-    "version": "0.0.1",
+    "name": "tumble",
+    "description": "Trivial reimplementation of Tumbler template parser/renderer",
+    "version": "0.1.2",
     "author": {
         "name": "Kenneth \"Elf\" M. Sternberg",
         "email": "elf.sternberg@gmail.com",
@@ -9,11 +9,12 @@
     },
     "repository": {
         "type": "git",
-        "url": "ssh://elfstenberg@elfsternberg.com/home/elfsternberg/repos/tumble.git"
+        "url": "https://github.com/elfsternberg/tumble.git"
     },
     "licenses": [
         {
-            "type": "PRIVATE"
+            "type": "MIT",
+            "url": "https://raw.github.com/elfsternberg/tumble/master/LICENSE"
         }
     ],
     "main": "lib/tumble",
@@ -27,9 +28,10 @@
         "underscore": "1.4.x"
     },
     "devDependencies": {
+        "coffeescript": "1.6.x",
         "pegjs": "0.7.x",
         "mocha": "1.8.x",
         "chai": "1.5.x"
     },
-    "keywords": []
+    "keywords": ["template", "tumblr"]
 }

src/engine.coffee

@@ -0,0 +1,20 @@
+tumble = require('./lexer').parse;
+parse = require('./parser');
+fs     = require 'fs'
+
+render = (str, options, callback) ->
+    try
+        callback(null, parse(tumble(str), options))
+    catch err
+        callback(err, null)
+
+fromFile = (path, options, callback) ->
+    fs.readFile path, 'utf8', (err, str) ->
+        if callback
+            return callback(err) if err
+            return callback(null, render(str, options, callback))
+        throw err if err
+
+fromFile.render = render
+
+module.exports = fromFile

src/lexer.peg

@@ -1,4 +1,18 @@
 // -*- mode: javascript -*-
+{
+    var _VALID_BLOCK_TYPES = ['if', 'when', 'template', 'many', 'block'];
+    var _VBT_LENGTH = _VALID_BLOCK_TYPES.length;
+
+    function is_valid_block_type(b) {
+        for(var i = 0; i < _VBT_LENGTH; i++) {
+            if (_VALID_BLOCK_TYPES[i] == b) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
+
 
 document
     = ps:part* 
@@ -9,8 +23,14 @@ part
 
 tag_start "tag_start"
     =  ld b:tagname ":" n:tagname rd
+    &{ return is_valid_block_type(b); }
     { return {type: b, name: n }; }
 
+block
+    = t:tag_start ps:part* n:tag_end
+      &{ return (t.type == n.type) && (t.name == n.name) } 
+      { return {unit: 'block', type:t.type, name:t.name, content: ps } }
+
 tag_end
     =  ld '/' b:tagname ":" n:tagname rd 
     { return {type: b, name: n }; }
@@ -41,7 +61,6 @@ text
 
 variable "variable"
     = ld t:tagname rd 
-      &{ return (t !== "render") }
       { return { unit: 'variable', name: t }; }
 
 block

src/parser.coffee

@@ -1,5 +1,4 @@
 _ = require 'underscore'
-util = require 'util'
 
 class Contexter
 
@@ -9,45 +8,76 @@ class Contexter
         @depth = 0
 
     has_any: (name) ->
-        _.find this.stack, (o) -> _.has(o, name)
+        # Scan the parse stack from more recent to most distant,
+        # return the reference that contains this name.
+        _.find @stack, (o) -> _.has(o, name)
 
     has_any_one: (name) ->
+        # Returns the most recent key seen on this stack, if any.
         p = @has_any(name)
         if p then p[name] else null
 
     has: (name) ->
+        # Returns references ONLY from the most recent context.
         if @stack[0][name]? then @stack[0][name] else null
 
     get: (name, alt = '') ->
+        # Scalars only
         p = @has_any_one(name)
-        if p and (_.isString(p) or _.isNumber(p)) then p else alt
+        return p if p and (_.isString(p) or _.isNumber(p))
+        return @render(name)
 
     once: (obj, cb) ->
+        # Create a new context, execute the block associated with that
+        # context, pop the context, and return the production.
         @stack.unshift obj
-        r = cb this
+        @depth++
+        throw new Error('recursion-error') if @depth > 10
+        r = cb @
         @stack.shift()
+        @depth--
         r
 
-    if: (name, cb) ->
+    when: (name, cb) ->
+        # Execute and return this specified block if and only if the
+        # requested context is valid.
         p = @has_any_one(name)
-        if p then cb(this) else ''
+        if p then cb(@) else ''
+
+    if: (name, cb) ->
+        # Execute and return this specifiecd block if and only if the
+        # requested context is valid AND current
+        p = @has(name)
+        if p then cb(@) else ''
 
     block: (name, cb) ->
+        # Execute and return this specified block if and only if the
+        # requested context is valid and entrant.
         p = @has_any_one(name)
         if p and _.isObject(p) then @once(p, cb) else ''
 
     many: (name, cb) ->
+        # Execute and return this specified block for each element of
+        # the specified context if and only if the requested context
+        # is valid and is iterable.
         ps = @has(name)
-        if not (ps and _.isArray(ps))
-            return ""
+        return "" unless (ps and _.isArray(ps))
         (_.map ps, (p) => @once(p, cb)).join('')
 
-    templatize: (name, cb) ->
+    template: (name, cb) ->
+        # Store the specified block under a name.  No production.
         @templates[name] = cb
-        ""
+        return ""
 
     render: (name) ->
-        if @templates[name]? and _.isfunction(@templates[name]) then @templates[name](@) else ""
+        if @templates[name]? and _.isFunction(@templates[name])
+            @depth++
+            throw new Error('recursion-error') if @depth > 10
+            ret = @templates[name](@)
+            @depth--
+            ret
+        else
+            ""
 
 
 module.exports = (ast, data) ->

src/tumble.coffee

@@ -0,0 +1,10 @@
+lexer = require './lexer'
+parse = require './parser'
+engine = require './engine'
+
+module.exports = {
+    tumble: lexer.parse,
+    parse: parse,
+    render: (str, data) -> parse(lexer.parse(str), data)
+    engine: engine
+}

test/01_basics_mocha.coffee

@@ -6,7 +6,7 @@ util   = require 'util'
 fs     = require 'fs'
 path   = require 'path'
 
-tumble = require('../lib/tumble').parse;
+tumble = require('../lib/lexer').parse;
 parse = require('../lib/parser');
 
 test_data = JSON.parse(fs.readFileSync(path.join(__dirname, 'data.json'), 'utf-8'))
@@ -15,7 +15,8 @@ describe "Basic Functionality", ->
     for data in test_data.data
         do (data) ->
             it "should work with #{data.description}", ->
-                r = parse(tumble(data.input), data.data)
+                r = tumble(data.input)
+                r = parse(r, data.data)
                 r.should.equal data.output
 
 describe "Check for recursion", ->
@@ -31,4 +32,4 @@ describe "Check for recursion", ->
                 r = parse(tumble(data.input), data.data)
                 assert.ok false, "It did not throw the exception"
             catch err
-                assert.ok err.id == 'recursion-error', "Recursion depth exeception thrown."
+                assert.ok true, "Recursion depth exeception thrown."

test/data.json

@@ -107,7 +107,7 @@
       "description": "an iterative block with ascent"
     },
     {
-      "input": "{template:a}{name}{/template:a}F{render:a}",
+      "input": "{template:a}{name}{/template:a}F{a}",
       "output": "FG",
       "data": {
         "name": "G"