Correct macro-require for relative paths

Calls to `require` in macros were resolving relative to the eslc
executable, not relative to the current working directory.  This fixes
that, such that cwd should always be used.

I thought existing tests were catching this, but turns out the test was
creating the temporary files that it used in the eslisp project
directory, which totally misses the point.  The files are now created in
a separate tmp directory, and the eslc command is run in full in that
dir.

Fixes #25.

Author: anko

makefile

@@ -14,7 +14,7 @@ lib/%.js: src/%.ls
 clean:
 	@rm -rf lib/
 
-test:
+test: all
 	@lsc test.ls
 
 test-readme: all readme.markdown

src/built-in-macros.ls

@@ -398,9 +398,25 @@ contents =
   \macro : (env, ...args) ->
 
     compile-as-macro = (es-ast) ->
-      # This is deliberately defined in the closure here, so it's in scope
-      # during the `eval` and available to the code being compiled.
-      root-require = require.main.require.bind require.main
+
+      # This hack around require makes loading macros from relative paths work.
+      #
+      # It was guided by LiveScript's implementation
+      # https://github.com/gkz/LiveScript/blob/a7525ce6fe7d4906f5d401edf94f15fe5a6b471e/src/node.ls#L10-L18
+      # which originally derives from the Coco language.
+      #
+      # The gist of it is to use the main module's `require` method, such that
+      # the current working directory is the root relative to which packages
+      # are searched.
+
+      {main} = require
+      dirname = "."
+      main
+        ..paths = main.constructor._node-module-paths process.cwd!
+        ..filename = dirname
+
+      root-require = main.require.bind main
+
       let require = root-require
         eval "(#{env.compile-to-js es-ast})"
 

test.ls

@@ -837,18 +837,32 @@ test "compiler types are converted to JS ones when passed to macros" ->
 
 test "macros can be required relative to root directory" ->
 
+  { exec-sync } = require \child_process
+
+  { name : dir-name, fd } = tmp.dir-sync!
+
   # Create dummy temporary file
-  file-name = "./#{uuid.v4!}.js"
-  fd = fs.open-sync file-name, \a+
-  fs.write-sync fd, "module.exports = function() { }"
+  module-basename = "#{uuid.v4!}.js"
+  module-path = path.join dir-name, module-basename
+  module-fd = fs.open-sync module-path, \a+
+  fs.write-sync module-fd, "module.exports = function() { }"
 
-  esl """
-    (macro (object x (require "#file-name")))
+
+  main-basename = "#{uuid.v4!}.js"
+  main-path = path.join dir-name, main-basename
+  main-fd = fs.open-sync main-path, \a+
+  fs.write-sync main-fd, """
+    (macro (object x (require "./#module-basename")))
     (x)
     """
-    ..`@equals` ""
 
-  fs.unlink-sync file-name
+  eslc-path = path.join process.cwd!, "bin/eslc"
+  try
+    exec-sync "#eslc-path #main-basename", cwd : dir-name
+      ..to-string! `@equals` "\n"
+  finally
+    e <~ rimraf dir-name
+    @equals e, null
 
 test "macros can be required from node_modules relative to root directory" ->