Make relative effectful (#25)

Author: m-rinaldi

CHANGELOG.md

@@ -5,6 +5,7 @@ Notable changes to this project are documented in this file. The format is based
 ## [Unreleased]
 
 Breaking changes:
+- `relative` now returns `Effect FilePath`, since Node resolves both arguments against the current working directory (#25)
 
 New features:
 

src/Node/Path.js

@@ -10,7 +10,7 @@ export function resolve(from) {
 }
 
 export function relative(from) {
-  return to => path.relative(from, to);
+  return to => () => path.relative(from, to);
 }
 
 export function dirname(p) {

src/Node/Path.purs

@@ -17,8 +17,10 @@ foreign import concat :: Array FilePath -> FilePath
 -- | Resolves `to` to an absolute path ([from...], to).
 foreign import resolve :: Array FilePath -> FilePath -> Effect FilePath
 
--- | Solve the relative path from `from` to `to`.
-foreign import relative :: FilePath -> FilePath -> FilePath
+-- | Solve the relative path from `from` to `to`. Both paths are resolved
+-- | against the current working directory first, so the result depends on it
+-- | whenever either path is relative.
+foreign import relative :: FilePath -> FilePath -> Effect FilePath
 
 -- | Return the directory name of a path.
 foreign import dirname :: FilePath -> FilePath

test/Test/Main.purs

@@ -10,7 +10,8 @@ main :: Effect Unit
 main = do
   assertEqual { actual: normalize "/foo/bar//baz/asdf/quux/..", expected: normalize "/foo/bar/baz/asdf" }
   assertEqual { actual: concat ["/foo", "bar"], expected: normalize "/foo/bar" }
-  assertEqual { actual: relative "/data/orandea/test/aaa" "/data/orandea/impl/bbb", expected: normalize "../../impl/bbb" }
+  rel <- relative "/data/orandea/test/aaa" "/data/orandea/impl/bbb"
+  assertEqual { actual: rel, expected: normalize "../../impl/bbb" }
   assertEqual { actual: dirname "/foo/bar/baz/asdf/quux", expected: normalize "/foo/bar/baz/asdf" }
   assertEqual { actual: basename "/foo/bar/baz/asdf/quux.html", expected: "quux.html" }
   assertEqual { actual: basenameWithoutExt "/foo/bar/baz/asdf/quux.html" ".html", expected: "quux" }