Makefile_Pandoc

GHC_VERSION ?= 8.4.4
CABAL_VERSION ?= 2.2.0.0
EPEL_VERSION ?= latest-7

TARGET_DIR ?= /opt/
PROJECT_ROOT = $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
CACHE_DIR=$(PROJECT_ROOT)build/cache

.ONESHELL:

### step 1: install GHC
# GHC is self-referential, so we need some version of GHC to install the latest version;
# so first install the older one that comes with EPEL on RPM, then update to the latest

GHC_SOURCE=ghc-$(GHC_VERSION)-x86_64-centos70-linux.tar.xz

/etc/yum.repos.d/epel.repo:
	curl -LO https://dl.fedoraproject.org/pub/epel/epel-release-$(EPEL_VERSION).noarch.rpm
	rpm -i epel-release-$(EPEL_VERSION).noarch.rpm

/usr/bin/ghc: /etc/yum.repos.d/epel.repo
	yum install ghc -y

$(GHC_SOURCE):
	curl -LO https://downloads.haskell.org/~ghc/$(GHC_VERSION)/$(GHC_SOURCE)

	
/usr/local/bin/ghc: $(GHC_SOURCE) /usr/bin/ghc
	tar xf $(GHC_SOURCE)
	rm $(GHC_SOURCE)
	cd ghc*
	./configure --prefix=/usr/local
	make install


### step 2: set up a cabal sandbox

CABAL_SOURCE=cabal-install-$(CABAL_VERSION)-x86_64-unknown-linux.tar.gz
	
$(CABAL_SOURCE): 
	curl -LO https://www.haskell.org/cabal/release/cabal-install-$(CABAL_VERSION)/$(CABAL_SOURCE)

/usr/local/bin/cabal: $(CABAL_SOURCE) /usr/local/bin/ghc
	tar xf $(CABAL_SOURCE)
	mv cabal /usr/local/bin

/root/.cabal/packages/hackage.haskell.org: /usr/local/bin/cabal
	cabal update

cabal.sandbox.config: /root/.cabal/packages/hackage.haskell.org
	cabal sandbox init --sandbox .

### step 3: compile pandoc


bin/pandoc: cabal.sandbox.config
	cabal install --disable-documentation pandoc -fembed_data_files 

$(TARGET_DIR)bin/pandoc: bin/pandoc
	mkdir -p $(TARGET_DIR)bin
	cp bin/pandoc $(TARGET_DIR)bin

all: $(TARGET_DIR)bin/pandoc