Rework strip flags to make clearer at in AST level

Rather than keeping state in the AST, which requires some gymnastics, we create a separate visitor flow which does the top down iteration necessary to calculate all of the state needed for proper whitespace control evaluation.

1 files changed, 21 insertions, 183 deletions

diff --git a/lib/handlebars/compiler/helpers.js b/lib/handlebars/compiler/helpers.js
index f215049..1daddf6 100644
--- a/lib/handlebars/compiler/helpers.js
+++ b/lib/handlebars/compiler/helpers.js
@@ -14,8 +14,8 @@ export function SourceLocation(source, locInfo) {
 
 export function stripFlags(open, close) {
   return {
-    left: open.charAt(2) === '~',
-    right: close.charAt(close.length-3) === '~'
+    open: open.charAt(2) === '~',
+    close: close.charAt(close.length-3) === '~'
   };
 }
 
@@ -69,9 +69,13 @@ export function prepareRawBlock(openRawBlock, content, close, locInfo) {
     throw new Exception(openRawBlock.sexpr.path.original + " doesn't match " + close, errorNode);
   }
 
+  locInfo = this.locInfo(locInfo);
   var program = new this.Program([content], null, {}, locInfo);
 
-  return new this.BlockStatement(openRawBlock.sexpr, program, undefined, undefined, locInfo);
+  return new this.BlockStatement(
+      openRawBlock.sexpr, program, undefined,
+      {}, {}, {},
+      locInfo);
 }
 
 export function prepareBlock(openBlock, program, inverseAndProgram, close, inverted, locInfo) {
@@ -85,192 +89,26 @@ export function prepareBlock(openBlock, program, inverseAndProgram, close, inver
 
   program.blockParams = openBlock.blockParams;
 
-  // Safely handle a chained inverse that does not have a non-conditional inverse
-  // (i.e. both inverseAndProgram AND close are undefined)
-  if (!close) {
-    close = {strip: {}};
-  }
-
-  // Find the inverse program that is involed with whitespace stripping.
-  var inverse = inverseAndProgram && inverseAndProgram.program,
-      firstInverse = inverse,
-      lastInverse = inverse;
-  if (inverse && inverse.inverse) {
-    firstInverse = inverse.body[0].program;
+  var inverse,
+      inverseStrip;
 
-    // Walk the inverse chain to find the last inverse that is actually in the chain.
-    while (lastInverse.inverse) {
-      lastInverse = lastInverse.body[lastInverse.body.length-1].program;
+  if (inverseAndProgram) {
+    if (inverseAndProgram.chain) {
+      inverseAndProgram.program.body[0].closeStrip = close.strip || close.openStrip;
     }
-  }
 
-  var strip = {
-    left: openBlock.strip.left,
-    right: close.strip.right,
-
-    // Determine the standalone candiacy. Basically flag our content as being possibly standalone
-    // so our parent can determine if we actually are standalone
-    openStandalone: isNextWhitespace(program.body),
-    closeStandalone: isPrevWhitespace((firstInverse || program).body)
-  };
-
-  if (openBlock.strip.right) {
-    omitRight(program.body, null, true);
-  }
-
-  if (inverse) {
-    var inverseStrip = inverseAndProgram.strip;
-
-    if (inverseStrip.left) {
-      omitLeft(program.body, null, true);
-    }
-
-    if (inverseStrip.right) {
-      omitRight(firstInverse.body, null, true);
-    }
-    if (close.strip.left) {
-      omitLeft(lastInverse.body, null, true);
-    }
-
-    // Find standalone else statments
-    if (isPrevWhitespace(program.body)
-        && isNextWhitespace(firstInverse.body)) {
-
-      omitLeft(program.body);
-      omitRight(firstInverse.body);
-    }
-  } else {
-    if (close.strip.left) {
-      omitLeft(program.body, null, true);
-    }
+    inverseStrip = inverseAndProgram.strip;
+    inverse = inverseAndProgram.program;
   }
 
   if (inverted) {
-    return new this.BlockStatement(openBlock.sexpr, inverse, program, strip, locInfo);
-  } else {
-    return new this.BlockStatement(openBlock.sexpr, program, inverse, strip, locInfo);
-  }
-}
-
-
-export function prepareProgram(body, isRoot) {
-  for (var i = 0, l = body.length; i < l; i++) {
-    var current = body[i],
-        strip = current.strip;
-
-    if (!strip) {
-      continue;
-    }
-
-    var _isPrevWhitespace = isPrevWhitespace(body, i, isRoot, current.type === 'partial'),
-        _isNextWhitespace = isNextWhitespace(body, i, isRoot),
-
-        openStandalone = strip.openStandalone && _isPrevWhitespace,
-        closeStandalone = strip.closeStandalone && _isNextWhitespace,
-        inlineStandalone = strip.inlineStandalone && _isPrevWhitespace && _isNextWhitespace;
-
-    if (strip.right) {
-      omitRight(body, i, true);
-    }
-    if (strip.left) {
-      omitLeft(body, i, true);
-    }
-
-    if (inlineStandalone) {
-      omitRight(body, i);
-
-      if (omitLeft(body, i)) {
-        // If we are on a standalone node, save the indent info for partials
-        if (current.type === 'PartialStatement') {
-          // Pull out the whitespace from the final line
-          current.indent = (/([ \t]+$)/).exec(body[i-1].original)[1];
-        }
-      }
-    }
-    if (openStandalone) {
-      omitRight((current.program || current.inverse).body);
-
-      // Strip out the previous content node if it's whitespace only
-      omitLeft(body, i);
-    }
-    if (closeStandalone) {
-      // Always strip the next node
-      omitRight(body, i);
-
-      omitLeft((current.inverse || current.program).body);
-    }
-  }
-
-  return body;
-}
-
-function isPrevWhitespace(body, i, isRoot) {
-  if (i === undefined) {
-    i = body.length;
-  }
-
-  // Nodes that end with newlines are considered whitespace (but are special
-  // cased for strip operations)
-  var prev = body[i-1],
-      sibling = body[i-2];
-  if (!prev) {
-    return isRoot;
-  }
-
-  if (prev.type === 'ContentStatement') {
-    return (sibling || !isRoot ? (/\r?\n\s*?$/) : (/(^|\r?\n)\s*?$/)).test(prev.original);
-  }
-}
-function isNextWhitespace(body, i, isRoot) {
-  if (i === undefined) {
-    i = -1;
-  }
-
-  var next = body[i+1],
-      sibling = body[i+2];
-  if (!next) {
-    return isRoot;
-  }
-
-  if (next.type === 'ContentStatement') {
-    return (sibling || !isRoot ? (/^\s*?\r?\n/) : (/^\s*?(\r?\n|$)/)).test(next.original);
-  }
-}
-
-// Marks the node to the right of the position as omitted.
-// I.e. {{foo}}' ' will mark the ' ' node as omitted.
-//
-// If i is undefined, then the first child will be marked as such.
-//
-// If mulitple is truthy then all whitespace will be stripped out until non-whitespace
-// content is met.
-function omitRight(body, i, multiple) {
-  var current = body[i == null ? 0 : i + 1];
-  if (!current || current.type !== 'ContentStatement' || (!multiple && current.rightStripped)) {
-    return;
-  }
-
-  var original = current.value;
-  current.value = current.value.replace(multiple ? (/^\s+/) : (/^[ \t]*\r?\n?/), '');
-  current.rightStripped = current.value !== original;
-}
-
-// Marks the node to the left of the position as omitted.
-// I.e. ' '{{foo}} will mark the ' ' node as omitted.
-//
-// If i is undefined then the last child will be marked as such.
-//
-// If mulitple is truthy then all whitespace will be stripped out until non-whitespace
-// content is met.
-function omitLeft(body, i, multiple) {
-  var current = body[i == null ? body.length - 1 : i - 1];
-  if (!current || current.type !== 'ContentStatement' || (!multiple && current.leftStripped)) {
-    return;
+    inverted = inverse;
+    inverse = program;
+    program = inverted;
   }
 
-  // We omit the last node if it's whitespace only and not preceeded by a non-content node.
-  var original = current.value;
-  current.value = current.value.replace(multiple ? (/\s+$/) : (/[ \t]+$/), '');
-  current.leftStripped = current.value !== original;
-  return current.leftStripped;
+  return new this.BlockStatement(
+      openBlock.sexpr, program, inverse,
+      openBlock.strip, inverseStrip, close && (close.strip || close.openStrip),
+      this.locInfo(locInfo));
 }