added README

oss-internship-2020/jsonnet/README.md

@@ -0,0 +1,29 @@
+# Jsonnet Sandboxed API
+
+This library provides sandboxed version of the [Jsonnet](https://github.com/google/jsonnet) library. 
+
+## Examples
+
+For now the only example command-line tool `jsonnet_sandboxed` enables the user to evaluate jsonnet code held in one file and writing to one output file. The tool is based on what can be found [here](https://github.com/google/jsonnet/blob/master/cmd/jsonnet.cpp) -- .
+
+## Build
+
+To build this example, after cloning the whole Sandbox API project, you also need to run
+
+```
+git submodule update --init --recursive
+```
+anywhere in the project tree in order to clone the `jsonnet` submodule.
+Then in the `sandboxed-api/oss-internship-2020/jsonnet` run
+```
+mkdir build && cd build
+cmake -G Ninja
+ninja
+```
+To run `jsonnet_sandboxed`:
+```
+cd examples
+./jsonnet_sandboxed absolute/path/to/the/input_file.jsonnet \ 
+    absolute/path/to/the/output_file
+```
+For now it supports evaluating one input file (possibly relying on multiple other files, e.x. by jsonnet `import` command; the files must be held in the same directory as input file) into one output file. Example jsonnet codes to evaluate can be found [here](https://github.com/google/jsonnet/tree/master/examples).