Clean up instrumentation code.

README.md

@@ -5,7 +5,7 @@ JavaScript execution logs.
 
 ![earhorn](https://raw.github.com/omphalos/earhorn/master/logo.jpg)
 
-Earhorn instruments your JavaScript and shows you a detailed, reversible, line-by-line log of JavaScript execution, sort of like a console.log on steroids.
+Earhorn instruments your JavaScript and shows you a detailed, reversible, line-by-line log of JavaScript execution, sort of like console.log's crazy uncle.
 
 Demo
 ====

earhorn.js

@@ -17,7 +17,7 @@
       bufferSize: 100,
       flushInterval: 25,
       handleErrors: true,
-      logModifiedCode: true,
+      verbose: false,
       quiet: true
     }
 
@@ -118,6 +118,21 @@
       return type.indexOf('Expression', type.length - 'Expression'.length) >= 0
     }
 
+    // Wrap Identifiers with calls to our logger, eh$(...)
+
+    scripts[name] = {
+      body: body,
+      modified: modified
+    }
+
+    function getLocationUpdate(node) {
+      return 'eh$loc="' +
+        (node.loc.start.line - 1) + ',' +
+        node.loc.start.column + ',' +
+        (node.loc.end.line - 1) + ',' +
+        node.loc.end.column + '"'
+    }
+
     var instrumentedExpressions = [
       'NewExpression',
       'CallExpression',
@@ -142,60 +157,6 @@
       'BinaryExpression',
       'ThrowStatement'
     ]
-
-    var skippedMemberExpressionParents = [
-      'AssignmentExpression',
-      'UnaryExpression',
-      'UpdateExpression',
-      'CallExpression', /*
-      'NewExpression' */
-    ]
-
-    // Wrap Identifiers with calls to our logger, eh$(...)
-
-    scripts[name] = {
-      body: body,
-      modified: modified
-    }
-
-    var handleErrors = settings.instrumentation.handleErrors
-      , tryPrefix = handleErrors ? 'var eh$log; try {' : ''
-      , catchSuffix = handleErrors ?
-        '} catch(err) { eh$("' + name +  '",eh$loc,err,true); throw err; }' :
-        ''
-
-    var instrumentedCode
-
-    try {
-      if(!settings.instrumentation.quiet)
-        console.log('parsing', name)
-      instrumentedCode = falafel(body, { loc: true, raw: true }, visitNode).toString()
-      scripts[name].parseError = null
-      announce(name)
-    } catch(err) {
-      console.error(name, err.toString(), body)
-
-      var e = err.toString()
-        , colon1 = e.indexOf(': ')
-        , colon2 = e.indexOf(': ', colon1 + 1)
-        , message = e.substring(colon2 + ': '.length)
-
-      scripts[name].parseError = {
-        line: err.lineNumber - 1,
-        ch: err.column,
-        message: message
-      }
-      announce(name)
-      throw err
-    }
-
-    function getLocationUpdate(node) {
-      return 'eh$loc="' +
-        (node.loc.start.line - 1) + ',' +
-        node.loc.start.column + ',' +
-        (node.loc.end.line - 1) + ',' +
-        node.loc.end.column + '"'
-    }
 
     function visitNode(node) {
 
@@ -209,11 +170,13 @@
       if(node.type === 'Literal')
         return
 
-      if(
+      if( 
         node.parent.type === 'BlockStatement' && node.parent.parent && (
         node.parent.parent.type === 'FunctionDeclaration' || 
         node.parent.parent.type === 'FunctionExpression')) {
 
+        // Add try/catch inside function bodies.
+
         if(node.parent.body[0] === node) {
           node.update(tryPrefix + node.source())
         }
@@ -226,8 +189,6 @@
       }
 
       if(
-        (node.parent.type === 'CallExpression' && 
-          node !== node.parent.callee) ||
         (node.parent.type === 'IfStatement' && 
           node === node.parent.test) ||
         (node.parent.type === 'WhileStatement' && 
@@ -240,16 +201,41 @@
           node === node.parent.discriminant) ||
         (node.parent.type === 'MemberExpression' && 
           node === node.parent.object) ||
+
         instrumentedExpressions.indexOf(node.type) >= 0 ||
-        (instrumentedParentTypes.
-          indexOf(node.parent.type) >= 0) ||
-        (node.type === 'MemberExpression' && 
-          skippedMemberExpressionParents.indexOf(node.parent.type) < 0)) {
-
+        (instrumentedParentTypes.indexOf(node.parent.type) >= 0) ||
+
+        (node.type === 'MemberExpression' &&
+
+          // Disallow eh$(eh$(a).b) = 123;
+          // Allow    eh$(a).b = 123;
+          node.parent.type !== 'AssignmentExpression' &&
+
+          // Disallow eh$(eh$(a).b)++;
+          // Allow    eh$(a).b++;
+          node.parent.type !== 'UpdateExpression' &&
+
+          /* Example explaining why we can't wrap CallExpression:
+               
+          // This works.
+          [].forEach(function() { })
+               
+          // This fails.
+          function returnArg(arg) { return arg }
+          returnArg([].forEach)(function() { })
+               
+          In the instrumented code we would have a call to eh$,
+          which is basically a fancy version of returnArg. */
+          node.parent.type !== 'CallExpression')) {
+
+        /* Add parens to fix NewExpression:        
+        new eh$(X)()   // Broken, without parens.
+        new (eh$(X)()) // Fixed, with parens. */
+
         var parenStart
           , parenEnd
-          
-        if(node.parent.type === 'NewExpression') {
+
+        if(node.parent.type === 'NewExpression') {  
           parenStart = '('
           parenEnd = ')'
         } else parenStart = parenEnd = ''
@@ -261,6 +247,37 @@
         ')' + parenEnd)
       }
     }
+
+    var handleErrors = settings.instrumentation.handleErrors
+      , tryPrefix = handleErrors ? 'var eh$log; try {' : ''
+      , catchSuffix = handleErrors ?
+        '} catch(err) { eh$("' + name +  '",eh$loc,err,true); throw err; }' :
+        ''
+
+    var instrumentedCode
+
+    try {
+      if(!settings.instrumentation.quiet)
+        console.log('parsing', name)
+      instrumentedCode = falafel(body, { loc: true, raw: true }, visitNode).toString()
+      scripts[name].parseError = null
+      announce(name)
+    } catch(err) {
+      console.error(name, err.toString(), body)
+
+      var e = err.toString()
+        , colon1 = e.indexOf(': ')
+        , colon2 = e.indexOf(': ', colon1 + 1)
+        , message = e.substring(colon2 + ': '.length)
+
+      scripts[name].parseError = {
+        line: err.lineNumber - 1,
+        ch: err.column,
+        message: message
+      }
+      announce(name)
+      throw err
+    }
 
     instrumentedCode =
       tryPrefix +

examples/todomvc-jquery/js/app.js

@@ -1,4 +1,4 @@
-earhorn$('app.js', /*global jquery, Handlebars */
+earhorn$('app.js', function() {/*global jquery, Handlebars */
 jQuery(function ($) {
 	'use strict';
 
@@ -181,4 +181,4 @@ jQuery(function ($) {
 	};
 
 	App.init();
-}));
+})})();