repl: add a 'writer' option to the repl

Previously this was a module-level setting, meaning that all REPL instances had to share the same writer function. Turning it into one of the options allows individual REPL instances to use their own writer function.
nodejs · Mar 28, 2012 · b187e96 · b187e96
1 parent 228dddd
commit b187e96
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Showing 2 changed files with 13 additions and 5 deletions.
diff --git a/doc/api/repl.markdown b/doc/api/repl.markdown
@@ -53,6 +53,10 @@ takes the following values:
  - `ignoreUndefined` - if set to `true`, then the repl will not output the
    return value of command if it's `undefined`. Defaults to `false`.
 
+ - `writer` - the function to invoke for each command that gets evaluated which
+   returns the formatting (including coloring) to display. Defaults to
+   `util.inspect`.
+
 You can use your own `eval` function if it has following signature:
 
     function eval(cmd, context, filename, callback) {

diff --git a/lib/repl.js b/lib/repl.js
@@ -66,7 +66,8 @@ module.filename = path.resolve('repl');
 // hack for repl require to work properly with node_modules folders
 module.paths = require('module')._nodeModulePaths(module.filename);
 
-// Can overridden with custom print functions, such as `probe` or `eyes.js`
+// Can overridden with custom print functions, such as `probe` or `eyes.js`.
+// This is the default "writer" value if none is passed in the REPL options.
 exports.writer = util.inspect;
 
 exports._builtinLibs = ['assert', 'buffer', 'child_process', 'cluster',
@@ -159,10 +160,13 @@ function REPLServer(prompt, stream, eval, useGlobal, ignoreUndefined) {
   this.commands = {};
   defineDefaultCommands(this);
 
+  // figure out which "writer" function to use
+  self.writer = options.writer || exports.writer;
+
   if (rli.terminal && !exports.disableColors &&
-      exports.writer === util.inspect) {
+      self.writer === util.inspect) {
     // Turn on ANSI coloring.
-    exports.writer = function(obj, showHidden, depth) {
+    self.writer = function(obj, showHidden, depth) {
       return util.inspect(obj, showHidden, depth, true);
     };
   }
@@ -224,7 +228,7 @@ function REPLServer(prompt, stream, eval, useGlobal, ignoreUndefined) {
                                 '" already exists globally\n');
       } else {
         self.context._ = self.context[cmd] = lib;
-        self.outputStream.write(exports.writer(lib) + '\n');
+        self.outputStream.write(self.writer(lib) + '\n');
       }
       self.displayPrompt();
       return;
@@ -293,7 +297,7 @@ function REPLServer(prompt, stream, eval, useGlobal, ignoreUndefined) {
       // If we got any output - print it (if no error)
       if (!e && (!self.ignoreUndefined || ret !== undefined)) {
         self.context._ = ret;
-        self.outputStream.write(exports.writer(ret) + '\n');
+        self.outputStream.write(self.writer(ret) + '\n');
       }
 
       // Display prompt again