Added the macroPaths option.

README.md

@@ -41,6 +41,8 @@ Here are the options handled by the plugin. A good share of them is used to conf
 
 - `macroPackages` is an array of macros to use. By default, the plugin tries to choose a classical macro package using the file extension.
 
+- `macroPaths` is an array of additional paths to search for macros. The default value is empty, see `man groff_tmac` for further explanation about the search sequence.
+
 - `preprocessors` is an array of preprocessors to be used by **groff**. Common preprocessors are `tbl`, `pic` or `soelim`. It is empty by default.
 
 - `pattern` is the matcher used to determine the files to be transformed. It is used with **[minimatch][]**. The default value (`**/*.@(me|mm|ms|mom)`) matches all files ending with `.ms`, `.me`, `.mm` or `.mom` at any depth.

lib/index.js

@@ -38,6 +38,7 @@ function plugin (options) {
     encoding: 'utf8',
     exe: 'groff',
     macroPackages: [],
+    macroPaths: [],
     preprocessors: [],
     pattern: '**/*.@(me|mm|ms|mom)',
     source: false
@@ -73,6 +74,17 @@ function plugin (options) {
     return arguments
   }
 
+  var configureMacroPaths = function (paths) {
+    let arguments = []
+
+    paths.forEach(p => {
+      arguments.push('-M')
+      arguments.push(p)
+    })
+
+    return arguments
+  }
+
   var configurePreprocessors = function (preprocessors) {
     const mapping = {
       chem: '-j',
@@ -103,6 +115,7 @@ function plugin (options) {
     let arguments = []
 
     arguments.push(configurePreprocessors(pluginOptions.preprocessors))
+    arguments.push(configureMacroPaths(pluginOptions.macroPaths))
     arguments.push(configureMacroPackages(pluginOptions.macroPackages, filename))
 
     arguments.push(['-K', pluginOptions.encoding])

test/index.js

@@ -75,6 +75,30 @@ describe('metalsmith-groff', function () {
           assert.strictEqual(arguments.shift(), macros.shift(), 'Unexpected macro!')
         }
       }
+      assert.equal(macros.length, 0, 'Macros mismatch!')
+    })
+  })
+
+  it('should use the given paths for the macros', function (done) {
+    let paths = ['/tmp', './here', '../another/path']
+
+    run(done, 'macros', {
+      macroPaths: paths
+    }, function (filename, file, log) {
+      let arguments = file.contents.toString('utf8').split(' ')
+
+      while (arguments.length > 0) {
+        let item = arguments.shift()
+
+        if (item === '-M') {
+          /* Order is not important. */
+          let p = arguments.shift(),
+              i = paths.indexOf(p)
+          assert.notEqual(i, -1, 'Found unknown path!')
+          paths.splice(i, 1)
+        }
+      }
+      assert.equal(paths.length, 0, 'Paths mismatch!')
     })
   })