Additions to Haskell's `Prelude` since `base-4.0.0.0`

Additions-to-Haskell-Prelude.md

Additions to Haskell's Prelude since base-4.0.0.0

base version	additions
4.8.0.0	*> <$ <$> <* <*> Applicative Foldable Monoid Traversable Word foldMap mappend mconcat mempty pure sequenceA traverse
4.9.0.0	errorWithoutStackTrace
4.11.0.0	<> Semigroup
4.13.0.0	MonadFail

Makefile

# Andreas Abel, 2021-12-08
# Extract 'since' information for Prelude memebership from sources.

# List functions

# From https://riptutorial.com/makefile/example/23643/zipping-lists, example:
#
# func = $1-$2
#
# all:
#     @echo $(call zipWith,func,$(LIST1),$(LIST2))
#
tail    = $(wordlist 2,$(words $1),$1)
zipWith = $(and $(strip $2),$(strip $3),$(call \
    $1,$(firstword $2),$(firstword $3)) $(call \
    zipWith,$1,$(call tail,$2),$(call tail,$3)))

# Variables

# working directories
dirs = Prelude only-idents word-lists added

# base versions
versions = \
  4.0.0.0 4.1.0.0 4.2.0.0 4.2.0.1 4.2.0.2 \
  4.3.0.0 4.3.1.0 4.4.0.0 4.4.1.0 4.5.0.0 4.5.1.0 \
  4.6.0.0 4.6.0.1 4.7.0.0 4.7.0.1 4.7.0.2 4.8.0.0 4.8.1.0 4.8.2.0 \
  4.9.0.0 4.9.1.0 4.10.0.0 4.10.1.0 4.11.0.0 4.11.1.0 \
  4.12.0.0 4.13.0.0 4.14.0.0 4.14.1.0 4.14.2.0 4.14.3.0 \
  4.15.0.0 4.16.0.0
# 3.0.3.1 3.0.3.2 ## not useful

tailVersions = $(call tail,$(versions))

# Prelude source files from hackage
preludes = $(patsubst %,Prelude/%.hs,$(versions))

# Only identifiers left over
onlyids = $(patsubst %,only-idents/%.txt,$(versions))

# Flattened to identifier lists
wordlists = $(patsubst %,word-lists/%.txt,$(versions))

# Difference to previous version
adds = $(patsubst %,added/%.txt,$(tailVersions))

# Commands

# onVersionPairs f = zipWith f versions (tail versions)
onVersionPairs = $(call zipWith,$1,$(versions),$(tailVersions))

# difference between word lists (only stuff that was added)
difference=$(shell comm -13 word-lists/$1.txt word-lists/$2.txt > added/$2.txt)

# Goals

.PHONY: default
default: all

.PHONY: all
all: $(dirs) fetch strip flatten diff Prelude-additions.md

$(dirs) : % :
	mkdir -p $@

# Getting Prelude source files from hackage

.PHONY: fetch
fetch: Prelude $(preludes)

$(preludes) : Prelude/%.hs :
	wget -O $@ https://hackage.haskell.org/package/base-$*/src/Prelude.hs

# Stripping comments and imports and syntax

.PHONY: strip
strip: only-idents $(onlyids)

# remove
# - block comments
# - line comments
# - preprocessor directives
# - 'import' lines
# - fixity directives
# - type signatures
# - keywords and other garbage: 'module' 'Prelude' 'where' 'let 'in' 'vx'
# - punctuation: ( , ) = ` ..
# - single letter variables and underscores
# - qualification
$(onlyids) : only-idents/%.txt : Prelude/%.hs Makefile
	gsed -e '/{-.*-}/d; /{-/,/-}/d; s/--.*//g; /^#/d; /^import/d; /^infix/d; /::/d; s/\<module\>//g; s/\<Prelude\>//g; s/\<where\>//g; s/\<let\>//g; s/\<in\>//g; s/\<vx\>//g; s/(/ /g; s/)/ /g; s/,/ /g; s/=/ /g; s/`/ /g; s/\.\./ /g; s/\<[a-z_]\>//g; s/[A-Z][a-zA-Z]*\.//g;' $< > $@

# Flatten and sort to identifier list

.PHONY: flatten
flatten: word-lists $(wordlists)

# - replace spaces by new lines
# - trim
# - sort
# - remove duplicates, !
$(wordlists) : word-lists/%.txt : only-idents/%.txt # Makefile
	tr " " "\n" < $< | gsed -e 's/\s+//g; /^\!$$/d;' | sort | uniq > $@

# Difference between word lists

.PHONY: diff
diff: added $(adds) # Makefile

# added/%.txt : word-lists/%.txt

$(adds) : $(wordlists) # Makefile
	$(call onVersionPairs,difference)

# Generate report
# - for each base version, report identifiers added over previous version
# - omit empty lines

Prelude-additions.md : $(adds) Makefile
	echo "# Additions to Haskell's \`Prelude\` since \`base-4.0.0.0\`\n" > $@
	echo "| \`base\` version | additions |" >> $@
	echo "|---|---|" >> $@
#	for ver in $(tailVersions); do if [ -s "added/$$ver.txt" ]; then cat "added/$$ver.txt" | xargs echo -n "| $$ver | " >> $@ ; echo " |" >> $@; fi; done
	for ver in $(tailVersions); do if [ -s "added/$$ver.txt" ]; then echo "| $$ver | \c" >> $@ ; for id in $$(cat "added/$$ver.txt"); do echo "\`$$id\` \c" >> $@; done; echo "|" >> $@; fi; done
# Note: \c suppresses final newline in echo

# Debugging

.PHONY: debug
debug:
	@echo "versions = $(versions)"
	@echo "preludes = $(preludes)"
	@echo "adds     = $(adds)"

# EOF

The outcome is embarrassing little. Instead of programming the Makefile for 2.5 hours, I could have spent 10 minutes to extract the information from https://hackage.haskell.org/package/base-4.16.0.0/changelog.
But as people say: Three months in the lab save you one hour in the library.