Pattern rules for using GNU make to build R projects on Windows

Makefile_R_Windows.mk

################################################################################
## Automatic rules ----
################################################################################

# First problem on windows: where to find Rscript if not on path
# RSCRIPT = "C:/Program Files/R/R-3.4.2/bin/x64/Rscript" --verbose
RSCRIPT = "Rscript" --verbose

	
# R files with Rout as target
# (including in subdirectories of ./R)
# Note: Input file needs to be sourced because input is UTF-8:
#   http://r.789695.n4.nabble.com/R-CMD-BATCH-Unicode-td4670311.html
#   https://stackoverflow.com/questions/1035388/unicode-output-on-windows-command-line
R/%.Rout:
	$(RSCRIPT) -e 'source("$<", encoding = "UTF-8", echo = TRUE)' > $@

# R data files with data file as target
# (including in subdirectories of ./data)
data/%.rds:
	$(RSCRIPT) -e 'source("$<", encoding = "UTF-8", echo = TRUE)' > $<.Rout


# Reports using Rmarkdown
# (including in subdirectories of ./rerpots)
# Need to ensure that target file extension corresponds to output type in file
reports/%.html: reports/%.Rmd
	$(RSCRIPT) -e 'rmarkdown::render("$<", encoding = "UTF-8", output_options = list(cache.rebuild = TRUE))' > $<.Rout

reports/%.pdf: reports/%.Rmd
	$(RSCRIPT) -e 'rmarkdown::render("$<", encoding = "UTF-8", output_options = list(cache.rebuild = TRUE))' > $<.Rout
	
	
# Phony target to find and make all markdown (Rmd) reports
RMD = $(wildcard reports/*.Rmd)
REPORTS = $(addsuffix .html, $(basename $(RMD)))

.PHONY : reports
reports : $(REPORTS) data

# A basic clean routine
.PHONY : clean
clean :
	rm -f R/*.Rout reports/*.Rout