diff --git a/Makefile b/Makefile
index 6b8106100..e9294f2c9 100644
--- a/Makefile
+++ b/Makefile
@@ -9,9 +9,9 @@ GNUMAKEFLAGS := --no-print-directory
 SUBMAKEFLAGS :=
 
 CLOE_ROOT   := $(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
-CLOE_LAUNCH := PYTHONPATH="${CLOE_ROOT}/cli" python3 -m cloe_launch
+CLOE_LAUNCH := PYTHONPATH="$(CLOE_ROOT)/cli" python3 -m cloe_launch
 
-include ${CLOE_ROOT}/Makefile.help
+include $(CLOE_ROOT)/Makefile.help
 
 # Set the clang-format command line to use:
 CLANG_FORMAT := $(shell command -v clang-format 2>/dev/null)
@@ -31,7 +31,7 @@ CONAN_OPTIONS   :=
 # Lockfile for cloe-meta:
 META_LOCKFILE_SOURCE := meta/conanfile.py
 META_BUILD_LOCKFILE  := meta/build/conan.lock
-META_LOCKFILE_OPTION := --lockfile="${CLOE_ROOT}/${META_BUILD_LOCKFILE}"
+META_LOCKFILE_OPTION := --lockfile="$(CLOE_ROOT)/$(META_BUILD_LOCKFILE)"
 
 .DEFAULT_GOAL := help
 .PHONY: help
@@ -46,11 +46,11 @@ help::
 # Setup targets ---------------------------------------------------------------
 include Makefile.setup
 
-${META_BUILD_LOCKFILE}:
-	${MAKE} -C meta LOCKFILE_SOURCE=conanfile.py lockfile
+$(META_BUILD_LOCKFILE):
+	$(MAKE) -C meta LOCKFILE_SOURCE=conanfile.py lockfile
 
 .PHONY: lockfile
-lockfile: ${META_BUILD_LOCKFILE}
+lockfile: $(META_BUILD_LOCKFILE)
 
 # Workspace targets -----------------------------------------------------------
 help::
@@ -61,60 +61,59 @@ help::
 .PHONY: docs
 docs:
 	$(call print_header, "Generating Doxygen documentation...")
-	${MAKE} -C docs doxygen
+	$(MAKE) -C docs doxygen
 	$(call print_header, "Generating Sphinx documentation...")
-	${MAKE} -C docs html
+	$(MAKE) -C docs html
 
 help::
-	$(call print_help_target, export-cli, "export ${_yel}cloe-launch-profile${_rst} Conan recipe")
-	$(call print_help_target, deploy-cli, "install ${_yel}cloe-launch${_rst} with ${_dim}${PIPX}${_rst}")
+	$(call print_help_target, export-cli, "export $(_yel)cloe-launch-profile$(_rst) Conan recipe")
+	$(call print_help_target, deploy-cli, "install $(_yel)cloe-launch$(_rst) with $(_dim)$(PIPX)$(_rst)")
 	echo
 
 .PHONY: export-cli
 export-cli:
-	${MAKE} -C cli export
+	$(MAKE) -C cli export
 
 .PHONY: deploy-cli
 deploy-cli:
 	$(call print_header, "Deploying cloe-launch binary with pip...")
-	${MAKE} -C cli install
+	$(MAKE) -C cli install
 
 help::
 	$(call print_help_target, lockfile, "create a lockfile for cloe-meta package")
 	$(call print_help_target, status-all, "show status of each of the Conan packages")
 	$(call print_help_target, export-all, "export all package sources to Conan cache")
 	$(call print_help_target, build-all, "build individual packages locally in-source")
-	$(call print_help_target, deploy-all, "deploy Cloe to INSTALL_DIR [=${INSTALL_DIR}]")
+	$(call print_help_target, deploy-all, "deploy $(_yel)cloe$(_rst) to $(_grn)INSTALL_DIR$(_rst)=$(_dim)$(INSTALL_DIR)$(_rst)")
 	$(call print_help_target, clean-all, "clean entire repository of temporary files")
 	$(call print_help_target, purge-all, "remove all cloe packages (in any version) from Conan cache")
 	echo
 
 .PHONY: build-all
 build-all: lockfile
-	${MAKE} all-select UNSELECT_PKGS="meta" CONAN_OPTIONS="${CONAN_OPTIONS} ${META_LOCKFILE_OPTION}"
+	$(MAKE) all-select UNSELECT_PKGS="meta" CONAN_OPTIONS="$(CONAN_OPTIONS) $(META_LOCKFILE_OPTION)"
 
 .PHONY: status-all
-status-all: ${META_BUILD_LOCKFILE}
-	@for pkg in ${ALL_PKGS}; do \
-		[ -d $${pkg} ] || continue; \
-		${MAKE} LOCKFILE_SOURCE="" LOCKFILE_OPTION=${META_LOCKFILE_OPTION} -C $${pkg} status || true; \
+status-all: $(META_BUILD_LOCKFILE)
+	@for pkg in $(ALL_PKGS); do \
+		$(MAKE) LOCKFILE_SOURCE="" LOCKFILE_OPTION=$(META_LOCKFILE_OPTION) -C $${pkg} status || true; \
 	done
 
 .PHONY: export-all
 export-all:
 	$(call print_header, "Exporting all cloe Conan packages...")
-	${MAKE} export-select export-cli export
+	$(MAKE) export-select export-cli export
 
 .PHONY: deploy-all
 deploy-all:
-	$(call print_header, "Deploying binaries to ${INSTALL_DIR}...")
-	conan install ${CONAN_OPTIONS} --install-folder ${BUILD_DIR}/deploy -g deploy .
-	mkdir -p ${INSTALL_DIR}
-	cp -r ${BUILD_DIR}/deploy/cloe-*/* ${INSTALL_DIR}/
+	$(call print_header, "Deploying binaries to $(INSTALL_DIR)...")
+	conan install $(CONAN_OPTIONS) --install-folder $(BUILD_DIR)/deploy -g deploy .
+	mkdir -p $(INSTALL_DIR)
+	cp -r $(BUILD_DIR)/deploy/cloe-*/* $(INSTALL_DIR)/
 
 .PHONY: clean-all
 clean-all:
-	${MAKE} clean clean-select
+	$(MAKE) clean clean-select
 
 .PHONY: purge-all
 purge-all:
@@ -137,19 +136,19 @@ format:
 	# continues to work as expected.
 	#
 	# See: https://www.moxio.com/blog/43/ignoring-bulk-change-commits-with-git-blame
-	find . -type f -not -path '*/\.git/*' -and \( -name '*.cpp' -o -name '*.hpp' \) -exec ${CLANG_FORMAT} ${CLANG_FORMAT_ARGS} -i {} \;
+	find . -type f -not -path '*/\.git/*' -and \( -name '*.cpp' -o -name '*.hpp' \) -exec $(CLANG_FORMAT) $(CLANG_FORMAT_ARGS) -i {} \;
 
 .PHONY: todos
 todos:
-	${AG} TODO
-	${AG} FIXME
-	${AG} XXX
+	$(AG) TODO
+	$(AG) FIXME
+	$(AG) XXX
 
 # Hidden development targets --------------------------------------------------
 
 .PHONY: grep-uuids
 grep-uuids:
-	${AG} "\b[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\b"
+	$(AG) "\b[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\b"
 
 .PHONY: find-missing-eol
 find-missing-eol:
diff --git a/Makefile.all b/Makefile.all
index 02668b3c4..e307c91af 100644
--- a/Makefile.all
+++ b/Makefile.all
@@ -37,12 +37,12 @@ SUBMAKEFLAGS :=
 
 META_PKG := meta
 PLUGIN_PKGS := plugins/basic plugins/clothoid_fit plugins/esmini plugins/gndtruth_extractor plugins/minimator plugins/mocks plugins/noisy_sensor plugins/speedometer plugins/virtue
-ALL_PKGS := fable runtime models osi oak engine ${PLUGIN_PKGS} ${META_PKG}
+ALL_PKGS := fable runtime models osi oak engine $(PLUGIN_PKGS) $(META_PKG)
 WITHOUT_PKGS :=
-UNSELECT_PKGS := ${WITHOUT_PKGS}
+UNSELECT_PKGS := $(WITHOUT_PKGS)
 WITH_PKGS :=
-SELECT_PKGS := $(call uniq, $(filter-out ${UNSELECT_PKGS}, ${ALL_PKGS}) ${WITH_PKGS})
-.PHONY: ${ALL_PKGS}
+SELECT_PKGS := $(call uniq, $(filter-out $(UNSELECT_PKGS), $(ALL_PKGS)) $(WITH_PKGS))
+.PHONY: $(ALL_PKGS)
 
 ## VENDOR PACKAGE SELECTION
 ##
@@ -50,10 +50,10 @@ SELECT_PKGS := $(call uniq, $(filter-out ${UNSELECT_PKGS}, ${ALL_PKGS}) ${WITH_P
 ##
 ALL_VENDOR := $(wildcard vendor/*)
 WITHOUT_VENDOR :=
-UNSELECT_VENDOR := ${WITHOUT_VENDOR}
+UNSELECT_VENDOR := $(WITHOUT_VENDOR)
 WITH_VENDOR :=
-SELECT_VENDOR := $(call uniq, $(filter-out ${UNSELECT_VENDOR}, ${ALL_VENDOR}) ${WITH_VENDOR})
-.PHONY: ${ALL_VENDOR}
+SELECT_VENDOR := $(call uniq, $(filter-out $(UNSELECT_VENDOR), $(ALL_VENDOR)) $(WITH_VENDOR))
+.PHONY: $(ALL_VENDOR)
 
 # Specify dependencies:
 fable:
@@ -62,9 +62,9 @@ models: runtime
 osi: runtime models vendor/open-simulation-interface
 oak: runtime
 engine: models oak
-${PLUGIN_PKGS}: runtime models
+$(PLUGIN_PKGS): runtime models
 plugins/esmini: vendor/open-simulation-interface vendor/esmini
-${META_PKG}: fable runtime models osi oak engine ${PLUGIN_PKGS}
+$(META_PKG): fable runtime models osi oak engine $(PLUGIN_PKGS)
 
 vendor/esmini: vendor/open-simulation-interface
 vendor/esmini-data:
@@ -99,36 +99,36 @@ CONAN_OPTIONS :=
 
 # Usage: $(call _make_target_rule, TARGET-NAME, MAKE-TARGET, HELP-DESCRIPTION, MAKE-ARGUMENTS)
 define _make_target_rule
-${1}:
-	$(call print_header, "Proceeding to $(call unquote, ${3})")
-	${MAKE} ${SUBMAKEFLAGS} ${4} ${2}
+$(1):
+	$(call print_header, "Proceeding to $(call unquote, $(3))")
+	$(MAKE) $(SUBMAKEFLAGS) $(4) $(2)
 endef
 
 # Usage: $(call _make_target_rules, TARGET-NAME, HELP-DESCRIPTION, HELP-CATEGORY, PACKAGE-DIRS)
 define _make_target_rules
 help::
-	$(call print_help_target, ${1}, ${2}, ${3})
-$(call _make_target_rule,${1},${1}-each,${2},-f Makefile.all)
-${1}-each: ${4}
+	$(call print_help_target, $(1), $(2), $(3))
+$(call _make_target_rule,$(1),$(1)-each,$(2),-f Makefile.all)
+$(1)-each: $(4)
 endef
 
 REGEX_TARGET := 's/(-vendor|-select)?-each//'
-${ALL_PKGS} ${ALL_VENDOR}:
-	${MAKE} -C $@ $(shell echo ${MAKECMDGOALS} | sed -re ${REGEX_TARGET})
+$(ALL_PKGS) $(ALL_VENDOR):
+	$(MAKE) -C $@ $(shell echo $(MAKECMDGOALS) | sed -re $(REGEX_TARGET))
 
 # Usage: $(call make_vendor_target, TARGET-NAME, HELP-DESCRIPTION, HELP-CATEGORY)
 define make_vendor_target
-$(eval $(call _make_target_rules,${1},${2},${3},${SELECT_VENDOR}))
+$(eval $(call _make_target_rules,$(1),$(2),$(3),$(SELECT_VENDOR)))
 endef
 
 # Usage: $(call make_every_target, TARGET-NAME, HELP-DESCRIPTION, HELP-CATEGORY)
 define make_every_target
-$(eval $(call _make_target_rules,${1},${2},${3},${ALL_PKGS}))
+$(eval $(call _make_target_rules,$(1),$(2),$(3),$(ALL_PKGS)))
 endef
 
 # Usage: $(call make_select_target, TARGET-NAME, HELP-DESCRIPTION, HELP-CATEGORY)
 define make_select_target
-$(eval $(call _make_target_rules,${1},${2},${3},${SELECT_PKGS}))
+$(eval $(call _make_target_rules,$(1),$(2),$(3),$(SELECT_PKGS)))
 endef
 
 # --------------------------------------------------------------------------- #
@@ -139,7 +139,7 @@ endef
 help::
 	$(call print_help_section, "Available multi-package targets")
 
-ifneq "${ALL_VENDOR}" ""
+ifneq "$(ALL_VENDOR)" ""
 help::
 $(call make_vendor_target, export-vendor, "export all vendor packages", "[conan-cache]")
 $(call make_vendor_target, package-vendor, "create all vendor packages", "[conan-cache]")
@@ -174,19 +174,19 @@ $(call make_select_target, clean-select, "remove build artifacts", "[in-source]"
 help::
 	echo
 	$(call print_help_subsection, "Options")
-ifneq "${ALL_VENDOR}" ""
-	$(call print_help_option, WITH_VENDOR, "", "include optional vendor packages from ${_grn}UNSELECT_VENDOR${_rst}")
+ifneq "$(ALL_VENDOR)" ""
+	$(call print_help_option, WITH_VENDOR, "", "include optional vendor packages from $(_grn)UNSELECT_VENDOR$(_rst)")
 endif
-	$(call print_help_option, WITH_PKGS, "", "include optional packages from ${_grn}UNSELECT_PKGS${_rst}")
+	$(call print_help_option, WITH_PKGS, "", "include optional packages from $(_grn)UNSELECT_PKGS$(_rst)")
 	$(call print_help_option, LOCKFILE_SOURCE, "", "use specified conanfile as lockfile source for build")
 	echo
 	$(call print_help_subsection, "Defines")
-	$(call print_help_option, BUILD_POLICY, ${BUILD_POLICY})
-	$(call print_help_define, CONAN_OPTIONS, ${CONAN_OPTIONS})
-ifneq "${ALL_VENDOR}" ""
-	$(call print_help_define_lines, UNSELECT_VENDOR, ${UNSELECT_VENDOR})
-	$(call print_help_define_lines, SELECT_VENDOR, ${SELECT_VENDOR})
+	$(call print_help_option, BUILD_POLICY, $(BUILD_POLICY))
+	$(call print_help_define, CONAN_OPTIONS, $(CONAN_OPTIONS))
+ifneq "$(ALL_VENDOR)" ""
+	$(call print_help_define_lines, UNSELECT_VENDOR, $(UNSELECT_VENDOR))
+	$(call print_help_define_lines, SELECT_VENDOR, $(SELECT_VENDOR))
 endif
-	$(call print_help_define_lines, UNSELECT_PKGS, ${UNSELECT_PKGS})
-	$(call print_help_define_lines, SELECT_PKGS, ${SELECT_PKGS})
+	$(call print_help_define_lines, UNSELECT_PKGS, $(UNSELECT_PKGS))
+	$(call print_help_define_lines, SELECT_PKGS, $(SELECT_PKGS))
 	echo
diff --git a/Makefile.docker b/Makefile.docker
index 69e41bef3..0576f9f78 100644
--- a/Makefile.docker
+++ b/Makefile.docker
@@ -2,61 +2,61 @@
 #
 # This file defines all Docker targets.
 
-PROJECT_ROOT := $(dir $(abspath $(lastword ${MAKEFILE_LIST})))
-PROJECT_VERSION := $(shell make --no-print-directory -C ${PROJECT_ROOT} -f Makefile.package info-version)
+PROJECT_ROOT := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
+PROJECT_VERSION := $(shell make --no-print-directory -C $(PROJECT_ROOT) -f Makefile.package info-version)
 
 UBUNTU_NAME := ubuntu
 UBUNTU_VERSIONS := 18.04 20.04 22.04
 
 DOCKER := DOCKER_BUILDKIT=1 docker
 DOCKER_IMAGE_NAME := cloe/cloe-engine
-DOCKER_IMAGE_VERSION := ${PROJECT_VERSION}
-DOCKER_IMAGE := ${DOCKER_IMAGE_NAME}:${DOCKER_IMAGE_VERSION}
-DOCKER_DEVIMAGE := ${DOCKER_IMAGE_NAME}-dev:${DOCKER_IMAGE_VERSION}
-DOCKER_CONTEXT := ${PROJECT_ROOT}
+DOCKER_IMAGE_VERSION := $(PROJECT_VERSION)
+DOCKER_IMAGE := $(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_VERSION)
+DOCKER_DEVIMAGE := $(DOCKER_IMAGE_NAME)-dev:$(DOCKER_IMAGE_VERSION)
+DOCKER_CONTEXT := $(PROJECT_ROOT)
 
 DOCKER_USER_ARGS +=
-DOCKER_BUILD_ARGS += --build-arg PROJECT_VERSION=${PROJECT_VERSION}
+DOCKER_BUILD_ARGS += --build-arg PROJECT_VERSION=$(PROJECT_VERSION)
 DOCKER_RUN_ARGS += --rm
 
-ifndef (${https_proxy},)
+ifndef ($(https_proxy),)
 	DOCKER_NETWORK := host
 	DOCKER_BUILD_ARGS += --network=host \
-						 --build-arg https_proxy="${https_proxy}" \
-						 --build-arg http_proxy="${http_proxy}" \
-						 --build-arg no_proxy="${no_proxy}"
+						 --build-arg https_proxy="$(https_proxy)" \
+						 --build-arg http_proxy="$(http_proxy)" \
+						 --build-arg no_proxy="$(no_proxy)"
 	DOCKER_RUN_ARGS += --network=host \
-						 --env https_proxy="${https_proxy}" \
-						 --env http_proxy="${http_proxy}" \
-						 --env no_proxy="${no_proxy}"
+						 --env https_proxy="$(https_proxy)" \
+						 --env http_proxy="$(http_proxy)" \
+						 --env no_proxy="$(no_proxy)"
 else
 	DOCKER_NETWORK := internal
 endif
 
-ifeq ($(shell [ -f ${PROJECT_ROOT}/setup.sh ] && echo "true"),true)
-DOCKER_BUILD_ARGS += --secret id=setup,src=${PROJECT_ROOT}/setup.sh
-DOCKER_RUN_ARGS += -v "${PROJECT_ROOT}/setup.sh:/root/setup.sh"
+ifeq ($(shell [ -f $(PROJECT_ROOT)/setup.sh ] && echo "true"),true)
+DOCKER_BUILD_ARGS += --secret id=setup,src=$(PROJECT_ROOT)/setup.sh
+DOCKER_RUN_ARGS += -v "$(PROJECT_ROOT)/setup.sh:/root/setup.sh"
 endif
 
-ifneq (${CONAN_PROFILE},)
-DOCKER_BUILD_ARGS += --build-arg CONAN_PROFILE="${CONAN_PROFILE}"
+ifneq ($(CONAN_PROFILE),)
+DOCKER_BUILD_ARGS += --build-arg CONAN_PROFILE="$(CONAN_PROFILE)"
 endif
 
-ifneq (${VENDOR_TARGET},)
-DOCKER_BUILD_ARGS += --build-arg VENDOR_TARGET="${VENDOR_TARGET}"
+ifneq ($(VENDOR_TARGET),)
+DOCKER_BUILD_ARGS += --build-arg VENDOR_TARGET="$(VENDOR_TARGET)"
 endif
 
-ifneq (${PACKAGE_TARGET},)
-DOCKER_BUILD_ARGS += --build-arg PACKAGE_TARGET="${PACKAGE_TARGET}"
+ifneq ($(PACKAGE_TARGET),)
+DOCKER_BUILD_ARGS += --build-arg PACKAGE_TARGET="$(PACKAGE_TARGET)"
 endif
 
-ifeq (${KEEP_SOURCES},1)
+ifeq ($(KEEP_SOURCES),1)
 DOCKER_BUILD_ARGS += --build-arg KEEP_SOURCES=1
 endif
 
 # -----------------------------------------------------------------------------
 
-include ${PROJECT_ROOT}/Makefile.help
+include $(PROJECT_ROOT)/Makefile.help
 
 .PHONY: help
 .SILENT: help
@@ -73,25 +73,25 @@ help::
 	$(call print_help_target, run-ubuntu-VERSION, "run the Ubuntu VERSION image")
 	$(call print_help_target, release-all, "release all Ubuntu versions")
 	$(call print_help_target, release-ubuntu-VERSION, "release the Ubuntu VERSION image")
-	$(call print_help_target, remove-current-images, "remove and prune all ${DOCKER_IMAGE} Docker images")
-	$(call print_help_target, remove-all-images, "remove and prune all ${DOCKER_IMAGE_NAME} Docker images")
+	$(call print_help_target, remove-current-images, "remove and prune all $(DOCKER_IMAGE) Docker images")
+	$(call print_help_target, remove-all-images, "remove and prune all $(DOCKER_IMAGE_NAME) Docker images")
 	echo
 	$(call print_help_section, "User configuration")
-	$(call print_help_define, CONAN_PROFILE, ${CONAN_PROFILE})
-	$(call print_help_define, VENDOR_TARGET, ${VENDOR_TARGET})
-	$(call print_help_define, PACKAGE_TARGET, ${PACKAGE_TARGET})
-	$(call print_help_define, KEEP_SOURCES, ${KEEP_SOURCES})
-	$(call print_help_args_lines, DOCKER_USER_ARGS, ${DOCKER_USER_ARGS})
+	$(call print_help_define, CONAN_PROFILE, $(CONAN_PROFILE))
+	$(call print_help_define, VENDOR_TARGET, $(VENDOR_TARGET))
+	$(call print_help_define, PACKAGE_TARGET, $(PACKAGE_TARGET))
+	$(call print_help_define, KEEP_SOURCES, $(KEEP_SOURCES))
+	$(call print_help_args_lines, DOCKER_USER_ARGS, $(DOCKER_USER_ARGS))
 	echo
 	$(call print_help_section, "Docker configuration")
-	$(call print_help_define, UBUNTU_NAME, "${UBUNTU_NAME}")
-	$(call print_help_define_lines, UBUNTU_VERSIONS, ${UBUNTU_VERSIONS})
-	$(call print_help_define, DOCKER, "${DOCKER}")
-	$(call print_help_define, DOCKER_CONTEXT, "${DOCKER_CONTEXT}")
-	$(call print_help_define, DOCKER_NETWORK, "${DOCKER_NETWORK}")
-	$(call print_help_define, DOCKER_IMAGE, "${DOCKER_IMAGE}")
-	$(call print_help_args_lines, DOCKER_BUILD_ARGS, ${DOCKER_BUILD_ARGS})
-	$(call print_help_args_lines, DOCKER_RUN_ARGS, ${DOCKER_RUN_ARGS})
+	$(call print_help_define, UBUNTU_NAME, "$(UBUNTU_NAME)")
+	$(call print_help_define_lines, UBUNTU_VERSIONS, $(UBUNTU_VERSIONS))
+	$(call print_help_define, DOCKER, "$(DOCKER)")
+	$(call print_help_define, DOCKER_CONTEXT, "$(DOCKER_CONTEXT)")
+	$(call print_help_define, DOCKER_NETWORK, "$(DOCKER_NETWORK)")
+	$(call print_help_define, DOCKER_IMAGE, "$(DOCKER_IMAGE)")
+	$(call print_help_args_lines, DOCKER_BUILD_ARGS, $(DOCKER_BUILD_ARGS))
+	$(call print_help_args_lines, DOCKER_RUN_ARGS, $(DOCKER_RUN_ARGS))
 	echo
 
 .SILENT: FORCE
@@ -101,61 +101,61 @@ FORCE:
 	# prerequisites of every target with patterns.
 
 .PHONY: build-all
-build-all: $(addprefix build-ubuntu-,${UBUNTU_VERSIONS})
+build-all: $(addprefix build-ubuntu-,$(UBUNTU_VERSIONS))
 
 .PHONY: test-all
-test-all: $(addprefix test-ubuntu-,${UBUNTU_VERSIONS})
+test-all: $(addprefix test-ubuntu-,$(UBUNTU_VERSIONS))
 
 .PHONY: release-all
-release-all: $(addprefix release-ubuntu-,${UBUNTU_VERSIONS})
+release-all: $(addprefix release-ubuntu-,$(UBUNTU_VERSIONS))
 
 ubuntu-%: FORCE build-ubuntu-% test-ubuntu-%
 	@echo
-	@echo "Completed building and testing: ${DOCKER_IMAGE}-$@"
+	@echo "Completed building and testing: $(DOCKER_IMAGE)-$@"
 
 .PHONY: all
-all: $(addprefix ubuntu-,${UBUNTU_VERSIONS})
+all: $(addprefix ubuntu-,$(UBUNTU_VERSIONS))
 
 build-devc-%: FORCE Dockerfile
-	${DOCKER} build -f Dockerfile ${DOCKER_BUILD_ARGS} ${DOCKER_USER_ARGS} \
+	$(DOCKER) build -f Dockerfile $(DOCKER_BUILD_ARGS) $(DOCKER_USER_ARGS) \
 		--build-arg UBUNTU_VERSION=$* \
 		--target stage-setup-system \
-		-t ${DOCKER_DEVIMAGE}-ubuntu-$* \
-		${DOCKER_CONTEXT}
+		-t $(DOCKER_DEVIMAGE)-ubuntu-$* \
+		$(DOCKER_CONTEXT)
 
 build-ubuntu-%: FORCE Dockerfile
-	${DOCKER} build -f Dockerfile ${DOCKER_BUILD_ARGS} ${DOCKER_USER_ARGS} \
+	$(DOCKER) build -f Dockerfile $(DOCKER_BUILD_ARGS) $(DOCKER_USER_ARGS) \
 		--build-arg UBUNTU_VERSION=$* \
-		-t ${DOCKER_IMAGE}-ubuntu-$* \
-		${DOCKER_CONTEXT}
+		-t $(DOCKER_IMAGE)-ubuntu-$* \
+		$(DOCKER_CONTEXT)
 
 test-ubuntu-%: FORCE
-	docker run ${DOCKER_RUN_ARGS} ${DOCKER_USER_ARGS} ${DOCKER_IMAGE}-ubuntu-$* \
+	docker run $(DOCKER_RUN_ARGS) $(DOCKER_USER_ARGS) $(DOCKER_IMAGE)-ubuntu-$* \
 		bash -ec "[ -f /root/setup.sh ] && source /root/setup.sh; make smoketest"
 
 run-devc-%: FORCE
-	docker run -it ${DOCKER_RUN_ARGS} ${DOCKER_USER_ARGS} --mount type=bind,source=$$(pwd),destination=/cloe ${DOCKER_DEVIMAGE}-ubuntu-$*
+	docker run -it $(DOCKER_RUN_ARGS) $(DOCKER_USER_ARGS) --mount type=bind,source=$$(pwd),destination=/cloe $(DOCKER_DEVIMAGE)-ubuntu-$*
 
 run-ubuntu-%: FORCE
-	docker run -it ${DOCKER_RUN_ARGS} ${DOCKER_USER_ARGS} ${DOCKER_IMAGE}-ubuntu-$*
+	docker run -it $(DOCKER_RUN_ARGS) $(DOCKER_USER_ARGS) $(DOCKER_IMAGE)-ubuntu-$*
 
 release-ubuntu-%: FORCE
 	@test -f setup.sh || echo 'Error: require setup.sh for user authentication'
-	${DOCKER} run ${DOCKER_RUN_ARGS} ${DOCKER_USER_ARGS} ${DOCKER_IMAGE}-ubuntu-$* \
+	$(DOCKER) run $(DOCKER_RUN_ARGS) $(DOCKER_USER_ARGS) $(DOCKER_IMAGE)-ubuntu-$* \
 		bash -ec 'source /root/setup.sh && upload_conan_packages'
 
 .PHONY: require-setup-sh
 require-setup-sh:
-	@if [ ! -f ${PROJECT_ROOT}/setup.sh ]; then \
-		echo "ERROR: require ${PROJECT_ROOT}/setup.sh to proceed"; \
+	@if [ ! -f $(PROJECT_ROOT)/setup.sh ]; then \
+		echo "ERROR: require $(PROJECT_ROOT)/setup.sh to proceed"; \
 		exit 1; \
 	fi
 
 .PHONY: remove-current-images
 remove-current-images:
-	docker rmi $$(docker images --format '{{.Repository}}:{{.Tag}}' | grep '${DOCKER_IMAGE}')
+	docker rmi $$(docker images --format '{{.Repository}}:{{.Tag}}' | grep '$(DOCKER_IMAGE)')
 
 .PHONY: remove-all-images
 remove-all-images:
-	docker rmi $$(docker images --format '{{.Repository}}:{{.Tag}}' | grep '${DOCKER_IMAGE_NAME}:')
+	docker rmi $$(docker images --format '{{.Repository}}:{{.Tag}}' | grep '$(DOCKER_IMAGE_NAME):')
 
diff --git a/Makefile.help b/Makefile.help
index 84fdc9b0f..2a0bc50a8 100644
--- a/Makefile.help
+++ b/Makefile.help
@@ -21,10 +21,10 @@
 
 # Usage: $(call assert_numeric_bool, VARIABLE-NAME)
 define assert_numeric_bool
-$(if $(filter-out 0 1,${$1}), $(error Unexpected value for parameter $1, expect either 0 or 1))
+$(if $(filter-out 0 1,$($1)), $(error Unexpected value for parameter $1, expect either 0 or 1))
 endef
 
-# Usage: $(call uniq, ${LIST-OF-WORDS})
+# Usage: $(call uniq, $(LIST-OF-WORDS))
 define uniq
 $(if $1,$(firstword $1) $(call uniq,$(filter-out $(firstword $1),$1)))
 endef
@@ -58,39 +58,39 @@ _dim := \e[2m
 define print_header
 	@printf "________________________________________"
 	@printf "________________________________________\n"
-	@printf ":: %s\n" ${1}
+	@printf ":: %s\n" $(1)
 endef
 
 # Usage: $(call print_help_section, SECTION-TITLE)
 define print_help_section
-	@printf "%s:\n" ${1}
+	@printf "%s:\n" $(1)
 endef
 
 # Usage: $(call print_help_subsection, SUBSECTION-TITLE)
 define print_help_subsection
-	@printf "  %s:\n" ${1}
+	@printf "  %s:\n" $(1)
 endef
 
 # Usage: $(call print_help_target, TARGET-NAME, HELP-DESCRIPTION, HELP-CATEGORY)
 define print_help_target
-	@printf "  ${_blu}% -21s${_rst} % -45b ${_dim}%s${_rst}\n" ${1} ${2} ${3}
+	@printf "  $(_blu)% -21s$(_rst) % -45b $(_dim)%s$(_rst)\n" $(1) $(2) $(3)
 endef
 
 # Usage: $(call print_help_option, VAR-NAME, VAR-DEFAULT, DESCRIPTION)
 define print_help_option
-	@printf "    % -36s %b\n" $(shell printf "${_grn}%s${_rst}=${_dim}%s${_rst}" ${1} ${2}) ${3}
+	@printf "    % -36s %b\n" $(shell printf "$(_grn)%s$(_rst)=$(_dim)%s$(_rst)" $(1) $(2)) $(3)
 endef
 
-# Usage: $(call print_help_define, VAR-NAME, ${VAR-NAME})
+# Usage: $(call print_help_define, VAR-NAME, $(VAR-NAME))
 define print_help_define
-	@printf "    ${_grn}%s${_rst}=${_dim}%s${_rst}\n" ${1} ${2}
+	@printf "    $(_grn)%s$(_rst)=$(_dim)%s$(_rst)\n" $(1) $(2)
 endef
 
 define print_help_define_align
-	@printf "    ${_grn}%-16s${_rst}=${_dim} %s${_rst}\n" ${1} ${2}
+	@printf "    $(_grn)%-16s$(_rst)=$(_dim) %s$(_rst)\n" $(1) $(2)
 endef
 
-# Usage: $(call print_help_define_lines, VAR-NAME, ${VAR-NAME})
+# Usage: $(call print_help_define_lines, VAR-NAME, $(VAR-NAME))
 #
 # For example, given a call with the following:
 #
@@ -103,16 +103,16 @@ endef
 #       20.04
 #       22.04
 #
-# If the contents of ${VAR-NAME} is empty or only contains whitespace,
+# If the contents of $(VAR-NAME) is empty or only contains whitespace,
 # then no extra newline is printed, and it behaves as print_help_define.
 define print_help_define_lines
-	@printf "    ${_grn}%s${_rst}=${_dim}" ${1}
-	@if [ -n "$(strip ${2})" ]; then printf "\\ \n"; fi
-	@printf "%s" "$$(echo "     ${2}" | fmt -5)"
-	@printf "${_rst}\n"
+	@printf "    $(_grn)%s$(_rst)=$(_dim)" $(1)
+	@if [ -n "$(strip $(2))" ]; then printf "\\ \n"; fi
+	@printf "%s" "$$(echo "     $(2)" | fmt -5)"
+	@printf "$(_rst)\n"
 endef
 
-# Usage: $(call print_help_args_lines, VAR-NAME, ${VAR-NAME})
+# Usage: $(call print_help_args_lines, VAR-NAME, $(VAR-NAME))
 #
 # This function behaves as print_help_define_lines, except that
 # it doesn't split on words, but on arguments. Each argument (leading with -)
@@ -129,12 +129,12 @@ endef
 #         --rm
 #         --network host
 #
-# If the contents of ${VAR-NAME} is empty, same behavior as print_help_define.
+# If the contents of $(VAR-NAME) is empty, same behavior as print_help_define.
 define print_help_args_lines
-	@printf "    ${_grn}%s${_rst}=${_dim}" ${1}
-	@if [ -n "$(strip ${2})" ]; then printf "\\ \n"; fi
-	@printf "%s" "$$(echo "     ${2}" | sed -r -e 's/\W--?[^-]/\n     \0/g' -e 's/^\s*\n//')"
-	@printf "${_rst}\n"
+	@printf "    $(_grn)%s$(_rst)=$(_dim)" $(1)
+	@if [ -n "$(strip $(2))" ]; then printf "\\ \n"; fi
+	@printf "%s" "$$(echo "     $(2)" | sed -r -e 's/\W--?[^-]/\n     \0/g' -e 's/^\s*\n//')"
+	@printf "$(_rst)\n"
 endef
 
 # Usage: $(call print_help_usage)
@@ -142,5 +142,5 @@ endef
 # This should be called only once, before all other print_help_* calls,
 # so that the help message starts with a usage statement.
 define print_help_usage
-	@printf "Usage: make ${_blu}target${_rst}\n"
+	@printf "Usage: make $(_blu)target$(_rst)\n"
 endef
diff --git a/Makefile.setup b/Makefile.setup
index d9ac0cb74..626d308d3 100644
--- a/Makefile.setup
+++ b/Makefile.setup
@@ -13,9 +13,9 @@ SHELL := /bin/bash
 PROJECT_ROOT := $(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
 CONAN_DIR := $(shell conan config home 2>/dev/null || echo "$HOME/.conan")
 CONAN_PROFILE := default
-CONAN_PROFILE_PATH := ${CONAN_DIR}/profiles/${CONAN_PROFILE}
+CONAN_PROFILE_PATH := $(CONAN_DIR)/profiles/$(CONAN_PROFILE)
 
-include ${PROJECT_ROOT}/Makefile.help
+include $(PROJECT_ROOT)/Makefile.help
 
 APT := $(or \
 	$(shell command -v apt 2>/dev/null), \
@@ -28,7 +28,7 @@ PIP := $(or \
 	$(shell command -v pip3 2>/dev/null), \
 	$(shell command -v pip 2>/dev/null) \
 )
-ifeq (${VIRTUAL_ENV}, )
+ifeq ($(VIRTUAL_ENV), )
 PIP_INSTALL_ARGS := --user --upgrade
 else
 PIP_INSTALL_ARGS := --upgrade
@@ -37,8 +37,8 @@ endif
 PIPX := $(shell command -v pipx 2>/dev/null)
 PIPX_INSTALL_ARGS :=
 ifndef PIPX
-PIPX := ${PIP}
-PIPX_INSTALL_ARGS := ${PIP_INSTALL_ARGS}
+PIPX := $(PIP)
+PIPX_INSTALL_ARGS := $(PIP_INSTALL_ARGS)
 endif
 
 .DEFAULT_GOAL := help
@@ -49,9 +49,9 @@ help::
 	$(call print_help_target, setup-git, "perform Git repository setup")
 	$(call print_help_target, setup-conan, "install Conan profile")
 	$(call print_help_target, install-system-deps, "install build (and development) system requirements")
-	$(call print_help_target, install-python-deps, "install Python runtime requirements with ${_dim}${PIP}${_rst}")
-	$(call print_help_target, install-sphinx-deps, "install Sphinx runtime requirements with ${_dim}${PIP}${_rst}")
-	$(call print_help_target, install-python-tools, "install Python development tools with ${_dim}${PIPX}${_rst}")
+	$(call print_help_target, install-python-deps, "install Python runtime requirements with $(_dim)$(PIP)$(_rst)")
+	$(call print_help_target, install-sphinx-deps, "install Sphinx runtime requirements with $(_dim)$(PIP)$(_rst)")
+	$(call print_help_target, install-python-tools, "install Python development tools with $(_dim)$(PIPX)$(_rst)")
 	echo
 
 .PHONY: setup-git
@@ -61,17 +61,17 @@ setup-git:
 .PHONY: setup-conan
 setup-conan:
 	# Install Conan if it is not available.
-	if ! command -v conan >/dev/null 2>&1; then ${PIP} install --user --upgrade "conan<2"; fi
+	if ! command -v conan >/dev/null 2>&1; then $(PIP) install --user --upgrade "conan<2"; fi
 	# Initialize Conan configuration if it doesn't already exist.
 	#
-	# Since running any conan command, even conan --help creates ${CONAN_DIR}
+	# Since running any conan command, even conan --help creates $(CONAN_DIR)
 	# and the default configuration, we rely on the existence of the default
 	# profile as an indication that we have a "fresh" setup where we can
 	# make our override.
-	if [ ! -f ${CONAN_PROFILE_PATH} ]; then \
+	if [ ! -f $(CONAN_PROFILE_PATH) ]; then \
 		conan config init; \
-		conan profile update settings.compiler.libcxx=libstdc++11 ${CONAN_PROFILE}; \
-		conan profile update settings.build_type=Debug ${CONAN_PROFILE}; \
+		conan profile update settings.compiler.libcxx=libstdc++11 $(CONAN_PROFILE); \
+		conan profile update settings.build_type=Debug $(CONAN_PROFILE); \
 	fi
 	if ! conan config get general.default_build_profile >/dev/null 2>&1; then \
 		conan config set general.default_build_profile=default; \
@@ -80,15 +80,15 @@ setup-conan:
 		conan config set general.revisions_enabled=True; \
 	fi
 	# Install cloe-{debug,normal,release} profiles.
-	for profile in "${PROJECT_ROOT}"/dist/conan/*.profile; do \
+	for profile in "$(PROJECT_ROOT)"/dist/conan/*.profile; do \
 		export profile_name=$$(basename -s .profile $${profile}); \
-		install -m 644 "$${profile}" "${CONAN_DIR}/profiles/$${profile_name}"; \
-		sed -r -i "s/default/${CONAN_PROFILE}/" "${CONAN_DIR}/profiles/$${profile_name}"; \
+		install -m 644 "$${profile}" "$(CONAN_DIR)/profiles/$${profile_name}"; \
+		sed -r -i "s/default/$(CONAN_PROFILE)/" "$(CONAN_DIR)/profiles/$${profile_name}"; \
 	done
 	# Ensure we have an up-to-date CMake configured.
 	if [ $$(( cmake --version | head -1 | cut -f3 -d' '; echo "3.14.99" ) | sort -V | tail -1) = "3.14.99" ]; then \
-		if ! grep "cmake/" ${CONAN_PROFILE_PATH} >/dev/null; then \
-			echo -e "[tool_requires]\ncmake/[>=3.15.0]" >> ${CONAN_PROFILE_PATH}; \
+		if ! grep "cmake/" $(CONAN_PROFILE_PATH) >/dev/null; then \
+			echo -e "[tool_requires]\ncmake/[>=3.15.0]" >> $(CONAN_PROFILE_PATH); \
 		fi; \
 	fi
 
@@ -102,8 +102,8 @@ endif
 
 .PHONY: install-ubuntu-deps
 install-ubuntu-deps::
-	command -v ${APT} >/dev/null 2>&1
-	${APT} install ${APT_ARGS} \
+	command -v $(APT) >/dev/null 2>&1
+	$(APT) install $(APT_ARGS) \
 		bats \
 		build-essential \
 		clang-format \
@@ -129,8 +129,8 @@ install-ubuntu-deps::
 		;
 
 	# Require GCC and G++ version >= 8
-	if [ "${UBUNTU_VERSION}" == "18.04" ]; then \
-		${APT} install ${APT_ARGS} gcc-8 g++-8; \
+	if [ "$(UBUNTU_VERSION)" == "18.04" ]; then \
+		$(APT) install $(APT_ARGS) gcc-8 g++-8; \
 		if [ $$(readlink /usr/bin/g++) == "g++-7" ]; then \
 			ln -sf /usr/bin/g++-8 /usr/bin/g++ && \
 			ln -sf /usr/bin/gcc-8 /usr/bin/gcc; \
@@ -140,8 +140,8 @@ install-ubuntu-deps::
 # Python ----------------------------------------------------------------------
 .PHONY: install-python-deps
 install-python-deps::
-	command -v ${PIP} >/dev/null 2>&1
-	${PIP} install ${PIP_INSTALL_ARGS} \
+	command -v $(PIP) >/dev/null 2>&1
+	$(PIP) install $(PIP_INSTALL_ARGS) \
 		click \
 		"conan<2.0.0" \
 		libtmux \
@@ -151,12 +151,12 @@ install-python-deps::
 
 .PHONY: install-sphinx-deps
 install-sphinx-deps:
-	command -v ${PIP} >/dev/null 2>&1
-	${PIP} install ${PIP_INSTALL_ARGS} -r docs/requirements.txt
+	command -v $(PIP) >/dev/null 2>&1
+	$(PIP) install $(PIP_INSTALL_ARGS) -r docs/requirements.txt
 
 .PHONY: install-python-tools
 install-python-tools::
-	command -v ${PIPX} >/dev/null 2>&1
+	command -v $(PIPX) >/dev/null 2>&1
 	for pkg in \
 		black \
 		mypy \
@@ -166,5 +166,5 @@ install-python-tools::
 		yq \
 		; \
 	do \
-		${PIPX} install ${PIPX_INSTALL_ARGS} $${pkg}; \
+		$(PIPX) install $(PIPX_INSTALL_ARGS) $${pkg}; \
 	done