[build] Migrate to dune / ocaml-migrate-parsetree / OPAM 2.0

Fixes ocaml-ppx#26. Changes:

- Build system migrated to Dune.
- Remove use of `cppo` in favor of ocaml-migrate-parsetree
- Introduce migration functions for elements of `Asttypes`
- Remove use of `topkg` in favor of `dune-release`
- Updated `.gitignore`
- Upgrade to OPAM 2.0
- Update Travis CI.

We had to raise dependencies on quite a few packages, thus ppx_import
now requires OCaml >= 4.04.2.

The question of whether we should use `ppx_tools_versioned` or
`ppxlib` does remain, but it can be addressed at a later point.

.gitignore

@@ -1,6 +1,4 @@
-*.native
-*.byte
-*.docdir
+*~
 _build
 *.install
-pkg/META
+.merlin

.travis.yml

@@ -1,19 +1,25 @@
 language: c
 env:
-  - OCAML=4.02.3
-  - OCAML=4.03.0
+  global:
+  - OPAMYES="true"
+  - OPAMJOBS="2"
+  matrix:
   - OCAML=4.04.2
   - OCAML=4.05.0
-  - OCAML=4.06.0
+  - OCAML=4.06.1
   - OCAML=4.07.0
 script:
-  - echo "yes" | sudo add-apt-repository ppa:avsm/ppa
+  # The opam package in this repository seems not to be working.
+  # - echo "yes" | sudo add-apt-repository ppa:avsm/ppa-opam-experimental
+  # - sudo apt-get install -qq opam
+  - echo "yes" | sudo add-apt-repository ppa:ansible/bubblewrap
   - sudo apt-get update -qq
-  - sudo apt-get install -qq opam
-  - export OPAMYES=1
-  - opam init
-  - eval `opam config env`
-  - opam switch $OCAML
+  - sudo apt-get install -qq bubblewrap
+  - sudo curl -sL https://github.com/ocaml/opam/releases/download/2.0.0/opam-2.0.0-x86_64-linux -o /usr/bin/opam
+  - sudo chmod 755 /usr/bin/opam
+  - opam init -c $OCAML
+  - opam switch set $OCAML
+  - eval $(opam env)
   - opam pin add -n -k path ppx_import .
   - opam install --deps-only -d -t ppx_import
   - opam install -d -t -v ppx_import

CHANGELOG.md → CHANGES.md

@@ -1,6 +1,14 @@
 Changelog
 =========
 
+1.6
+---
+
+  * ocaml-migrate-parsetree + dune support #26
+    (Jérémie Dimino & Emilio Jesús Gallego Arias)
+
+  * Move to OPAM 2.0, adapt Travis CI.
+
 1.5
 ---
 

Makefile

@@ -1,15 +1,13 @@
 build:
-	cp pkg/META.in pkg/META
-	ocaml pkg/build.ml native=true native-dynlink=true
+	dune build
 
-test: build
-	rm -rf _build/src_test
-	ocamlbuild -j 0 -use-ocamlfind -classic-display src_test/test_ppx_import.native --
+test:
+	dune runtest
 
 clean:
-	ocamlbuild -clean
+	dune clean
 
-.PHONY: build test clean
+.PHONY: build test clean release
 
 VERSION      := $$(opam query --version)
 NAME_VERSION := $$(opam query --name-version)
@@ -21,5 +19,3 @@ release:
 	opam publish prepare $(NAME_VERSION) $(ARCHIVE)
 	opam publish submit $(NAME_VERSION)
 	rm -rf $(NAME_VERSION)
-
-.PHONY: release

dune-project

@@ -0,0 +1,2 @@
+(lang dune 1.1)
+

dune-workspace

@@ -0,0 +1,5 @@
+(lang dune 1.1)
+
+(env
+ (dev     (flags :standard))
+ (release (flags :standard)))