some docs

README.md

@@ -0,0 +1,28 @@
+# PSIL
+
+a simple lisp interpreter
+
+## How to compile
+
+Should be a regular cmake build, something like
+
+```shell
+cmake -B build -DCMAKE_BUILD_TYPE=Debug -DSANITIZE=YES
+cmake --build build  --parallel $(nproc)
+```
+
+should be enough (you can also change the build type for Release and disable sanitize in case it's too slow)
+
+## How to run tests
+
+Unit tests (assuming build in `build`):
+
+```shell
+ctest --test-dir build --verbose --parallel $(nproc)
+```
+
+CLI tests (also assuming build in `build` and being in repo root):
+
+```shell
+PSIL="../build/src/psil" clitests/testall.sh
+```