experimental pragma support

{%esc:j}{foo}{/esc}

lib/compiler.js

@@ -26,6 +26,7 @@ dust.optimizers = {
   "<":       visit,
   "+":       visit,
   "@":       visit,
+  "%":       visit,
   partial:   visit,
   context:   visit,
   params:    visit,
@@ -38,6 +39,17 @@ dust.optimizers = {
   comment:   nullify
 }
 
+dust.pragmas = {
+  esc: function(compiler, context, bodies, params) {
+    var old = compiler.auto;
+    if (!context) context = 'h';
+    compiler.auto = (context === 's') ? '' : context;
+    var out = compileParts(compiler, bodies.block);
+    compiler.auto = old;
+    return out;
+  }
+}
+
 function visit(context, node) {
   var out = [node[0]];
   for (var i=1, len=node.length; i<len; i++) {
@@ -126,20 +138,22 @@ function compileBodies(context) {
   return out.join('');
 }
 
+function compileParts(context, body) {
+  var parts = '';
+  for (var i=1, len=body.length; i<len; i++) {
+    parts += dust.compileNode(context, body[i]);
+  }
+  return parts;
+}
+
 dust.compileNode = function(context, node) {
   return dust.nodes[node[0]](context, node);
 }
 
 dust.nodes = {
   body: function(context, node) {
-    var id = context.index++,
-        name = "body_" + id,
-        parts = '';
-
-    for (var i=1, len=node.length; i<len; i++) {
-      parts += dust.compileNode(context, node[i]);
-    }
-    context.bodies[id] = parts;
+    var id = context.index++, name = "body_" + id;
+    context.bodies[id] = compileParts(context, node);
     return name;
   },
 
@@ -199,6 +213,30 @@ dust.nodes = {
       + ")";
   },
 
+  "%": function(context, node) {
+    // TODO: Move these hacks into pragma precompiler
+    var name = node[1][1];
+    if (!dust.pragmas[name]) return '';
+
+    var rawBodies = node[4];
+    var bodies = {};
+    for (var i=1, len=rawBodies.length; i<len; i++) {
+      var b = rawBodies[i];
+      bodies[b[1][1]] = b[2];
+    }
+
+    var rawParams = node[3];
+    var params = {};
+    for (var i=1, len=rawParams.length; i<len; i++) {
+      var p = rawParams[i];
+      params[p[1][1]] = p[2][1];
+    }
+
+    var ctx = node[2][1] ? node[2][1].text : null;
+
+    return dust.pragmas[name](context, ctx, bodies, params);
+  },
+
   partial: function(context, node) {
     return ".partial("
       + dust.compileNode(context, node[1])
@@ -241,7 +279,8 @@ dust.nodes = {
       var filter = node[i];
       list.push("\"" + filter + "\"");
     }
-    return "\"" + context.auto + "\",[" + list.join(',') + "]";
+    return "\"" + context.auto + "\""
+      + (list.length ? ",[" + list.join(',') + "]" : '');
   },
 
   key: function(context, node) {

lib/dust.js

@@ -78,14 +78,14 @@ dust.isEmpty = function(value) {
 };
 
 dust.filter = function(string, auto, filters) {
-  var len = filters.length;
-
-  for (var i=0; i<len; i++) {
-    var name = filters[i];
-    if (name === "s") {
-      auto = null;
-    } else {
-      string = dust.filters[name](string);
+  if (filters) {
+    for (var i=0, len=filters.length; i<len; i++) {
+      var name = filters[i];
+      if (name === "s") {
+        auto = null;
+      } else {
+        string = dust.filters[name](string);
+      }
     }
   }
   if (auto) {
@@ -95,16 +95,9 @@ dust.filter = function(string, auto, filters) {
 };
 
 dust.filters = {
-  h: function(value) {
-    return dust.escapeHtml(value);
-  },
-
-  j: function(value) {
-    return dust.escapeJs(value);
-  },
-
+  h: function(value) { return dust.escapeHtml(value); },
+  j: function(value) { return dust.escapeJs(value); },
   u: encodeURI,
-
   uc: encodeURIComponent
 }
 

src/dust.pegjs

@@ -22,7 +22,7 @@ section "section"
   { t.push(["bodies"]); return t }
 
 sec_tag_start
-  = ld t:[#?^<+@] n:identifier c:context p:params
+  = ld t:[#?^<+@%] n:identifier c:context p:params
   { return [t, n, c, p] }
 
 end_tag "end tag"
@@ -98,7 +98,7 @@ comment "comment"
   { return ["comment", c.join('')] }
 
 tag
-  = ld [#?^><+%:@/~] (!rd !eol .)+ rd
+  = ld [#?^><+%:@/~%] (!rd !eol .)+ rd
   / reference
 
 ld