chreke / jet

Jet is a scripting language for text processing

Jet

Jet is a cross-platform scripting language for text manipulation

Examples

# Output all lines from input.txt that contain "banana"
cat input.txt | jet 'filter /banana/' 

Motivation

The motivation for Jet is that I want a cross-platform scripting language which can be used for a variety of text manipulation tasks.

When I used to program Perl I realized that I could use it replace most of my uses of grep, sed, etc. While having a single program that does a lot of different things goes pretty hard against the Unix philosophy, I would say it has its benefits. Having a single tool that does everything means you don't have to remember the command line options and quirks of a collection of disparate tools.

Also, if the single tool is portable it means it will work the same anywhere; for example, you won't have to ask yourself questions like "does this system have the GNU or BSD version of sed?"

Types

Under the hood, Jet is a statically typed functional programming language. All Jet programs should have the function signature (List String) -> a.

Having Jet being a statically typed langauge brings certain benefits:

• Incorrect programs will not start, as opposed to crashing in the middle of a long run
• As Jet doesn't allow recursion it is total, ie if the program compiles it will never crash or hang
• Type inference allows automatic coercion of input arguments and automatic generation of help messages

Safety

Jet scripts are more secure than e.g. Bash or Python as they only operate on string streams; a script can't "shell out" or otherwise touch other parts of the operating system.