Updated Runtime Environments (markdown)

Runtime-Environments.md

@@ -1,19 +1,24 @@
 # Runtime Environments
 
-This page contains notes about using various runtime environments in ReCodEx as well as their internal usage inside [isolate](https://github.com/ioi/isolate) sandbox. Only special cases are noted here.
+This page contains notes about using various runtime environments in ReCodEx as well as their internal usage inside [isolate](https://github.com/ioi/isolate) sandbox. At present ReCodEx supports
+* C
+* C++
+* C#
+* Data-only
+* Go
+* Haskell
+* Java (OpenJDK)
+* JavaScript (Node.js)
+* Pascal
+* PHP (CLI apps)
+* Prolog (SWI)
+* Python 3
+* Rust
+
+Exercises may be configured for multiple environments, so the student may choose the language for the solution. However, Data-only, Haskell, and Prolog have somewhat unique configurations. They are designated *separated* runtime environments which means an exercise must use such environment exclusively.
+
+Only environments which needed some special treatment are noted here.
 
-## Python
-
-We use a wrapper script that translates exceptions to error codes. This script can be found in the [utils](https://github.com/ReCodEx/utils/blob/master/runners/py/runner.py) repository. The file is named `runner.py` during execution of solutions, so be aware of filename collisions.
-
-Due to a [Python bug](http://bugs.python.org/issue10496), the interpreter 
-requires the `$HOME` variable to be set to something. Otherwise, it tries to 
-look up the UID used by Isolate in `/etc/passwd` and fails. Setting `HOME=/box` 
-seems to work.
-
-## Java
-
-By default, we use a script that looks for a class with a `main` method and executes it for running Java programs. There has to be only one class containing `main` method, otherwise error will be observed. The executed script is named `javarun.java` and can be found in the [utils](https://github.com/ReCodEx/utils/blob/master/runners/java/javarun.java) repository. In tested solutions we use its byte-compiled counterpart `javarun.class`, so be aware of name collisions.
 
 ## C#
 
@@ -21,6 +26,22 @@ The C# solutions are executed with the help of [wrapper code](https://github.com
 
 In C# language there are none of the handy functions to operate with textual inputs like `scanf` in C. Therefore for every C# build in ReCodEx there is [Reader](https://github.com/ReCodEx/utils/blob/master/runners/cs/Reader.cs) library included to make life of C# programmers easier. Please note that library is suppose to work only with ASCII files and some difficulties can be observed with modern Unicode (UTF-8) encodings. The `Reader` library is located in `ReCodEx_Csharp_Reader.cs` library contains namespace `CodEx` with class `Reader`, so again, be aware of filename and class collisions.
 
+
 ## Go
 
 The solutions of Go has to be located only in one package, the standard `main` executable package. ReCodEx uses flat folder structure of submitted solution, therefore separate Go packages cannot be used. Multiple files are fine as long as they contain the same package.
+
+
+## Java
+
+By default, we use a script that looks for a class with a `main` method and executes it for running Java programs. There has to be only one class containing `main` method, otherwise error will be observed. The executed script is named `javarun.java` and can be found in the [utils](https://github.com/ReCodEx/utils/blob/master/runners/java/javarun.java) repository. In tested solutions we use its byte-compiled counterpart `javarun.class`, so be aware of name collisions.
+
+
+## Python
+
+We use a wrapper script that translates exceptions to error codes. This script can be found in the [utils](https://github.com/ReCodEx/utils/blob/master/runners/py/runner.py) repository. The file is named `runner.py` during execution of solutions, so be aware of filename collisions.
+
+Due to a [Python bug](http://bugs.python.org/issue10496), the interpreter 
+requires the `$HOME` variable to be set to something. Otherwise, it tries to 
+look up the UID used by Isolate in `/etc/passwd` and fails. Setting `HOME=/box` 
+seems to work.