Jsh Team 32

This repository refactors and extends the legacy JSH shell.

JSH

The following are the classes that JSH is built with:

Jsh

Jsh is the main class. The program enters in the PSVM located in this class, and the main function calls either the interactive shell, or if the -c flag was passed, executes whatever command is after said -c flag on the command line.

Sequence

Semicolon
When executing a command, Sequence is the first class that the code enters. Sequence splits the given string into multiple commands if there are more than one command separated by a semicolon (as according to specification).

After splitting commands, each command is passed to the Pipe class as a String.

Pipe

Pipe takes a String command, and splits into multiple commands if there is at least one pipe operator (that isn't inside quotes).

Pipe will then create appropriate input and output streams for each of the command in order to pass the outputs of one command into the input of another; Pipe will then print to the original output stream once all commands have been executed.

Once the commands are split, each command is sent to the Call class.

Call

Call receives a String as the command, as well as an input stream and an output stream.

Substitution
Command substitution is first performed on the given String.
Quoting
A method in Call splits the resulting string given by the command substitution is then split into tokens in such a way that quoted arguments stay as a single token, while the rest of the tokens are space-delimited.
IO redirection
A method in Call then scans trough the tokens looking for redirection operators. When found, the input stream and output stream passed to Call gets overridden by FileInputStream or/and FileOutputStream, depending on the given redirection operator. The tokens corresponding to IO redirection are then removed from the token array.
Globbing
Another method in Call scans through the tokens again and tries to replace all arguments that contain a * that is also unquoted (a glob pattern) to a file that matches the pattern in the present working directory. All quoted content is ignored.
Quoting (pass 2)
Once IO redirection and globbing have been performed, a different method from the first quoting method will then remove quotes from the input arguments, where they aren't inside other quotes (in which case they are kept).