feat: Support using venvs instead of pypackages

Handle creation of multiple venvs with Makefile and `setup.sh`.

Related to pawamoy/pdm-multirun#10: pawamoy/pdm-multirun#10
Co-authored-by: Timothée Mazzucotelli <pawamoy@pm.me>

docs/work.md

@@ -229,14 +229,25 @@ The first thing you should run when entering your repository is:
 make setup
 ```
 
+If you don't have the `make` command,
+you can use `bash scripts/setup.sh` directly,
+or even just `pdm install`
+if you don't plan on using multiple Python versions.
+
 This will install the project's dependencies in `__pypackages__`:
 one folder per chosen Python version.
 The chosen Python versions are defined in the Makefile.
+If you would like to use *virtual environments (venvs)* instead,
+set the PDM configuration item `python.use_venv` to true:
 
-If you don't have the `make` command,
-you can use `bash scripts/setup.sh` instead,
-or even just `pdm install`
-if you don't plan on using multiple Python versions.
+```bash
+pdm config --local python.use_venv
+```
+
+Remove the `--local` flag to enable using venvs for all your local projects.
+
+When venvs are enabled, the setup script will create named venvs (`name=3.xx`) 
+in your `venv.location` directory (PDM configuration).
 
 Now you can start writing and editing code in `src/your_package`.
 

project/Makefile.jinja

@@ -2,6 +2,7 @@
 SHELL := bash
 DUTY := $(if $(VIRTUAL_ENV),,pdm run) duty
 export PDM_MULTIRUN_VERSIONS ?= 3.8 3.9 3.10 3.11 3.12
+export PDM_MULTIRUN_USE_VENVS ?= $(if $(shell pdm config python.use_venv | grep True),1,0)
 
 args = $(foreach a,$($(subst -,_,$1)_args),$(if $(value $a),$a="$($a)"))
 check_quality_args = files

project/scripts/setup.sh

@@ -12,6 +12,13 @@ if ! pdm self list 2>/dev/null | grep -q pdm-multirun; then
 fi
 
 if [ -n "${PDM_MULTIRUN_VERSIONS}" ]; then
+    if [ "${PDM_MULTIRUN_USE_VENVS}" -eq "1" ]; then
+        for version in ${PDM_MULTIRUN_VERSIONS}; do
+            if ! pdm venv --path "${version}" &>/dev/null; then
+                pdm venv create --name "${version}" "${version}"
+            fi
+        done
+    fi
     pdm multirun -v pdm install -G:all
 else
     pdm install -G:all