JSPM

pyx scripting language

- the pyx educational programming language / scripting langauge and REPL shell. With pyx you can write code in functional and procedural style.

This programming language is named after Winnie-the-Pooh, in the Russian translation of Boris Zahoder

The scripting language and interpreter for the pyx language.

• See pyx tutorial (pyxtut)
• See pyx functions by category (pyxfunc)
• see the design document (pyxdesign)
• Example tests scripts are here - see files with extension .p (.out - expected output of the script)

Running it

First we need the to install node.js - you can download an installer here

Now, from the command line: Install the pyx shell with the following command

npm install pyxlang -g

Now run the shell

pyx

The shell has command completion (tab tab) and a command history (cursor up, cursor down)

You can also run one-line commands as follows

pyx -e 'println("hello world")'

or run any saved source file with

pyx source.p

You can also run the program in trace mode, by adding the -x option to the command line. Here each statement is shown, as it is executed.

./pyx -x tests/03-func-if.p
foo(val=6)
+ if true
+ println("should be happy years") {
should be happy years
+ }
+ }
foo(val=20)
+ if false # <pass>
+ elif true
+ println("youth age") {
youth age
+ }
+ }
foo(val=42)
+ if false # <pass>
+ elif false # <pass>
+ else
+ println("after youth age") {
after youth age
+ }
+ }
+ }

Source code

• the interpreter/repl script is here - you need to have node installed for this.
• The parser/syntax tree is built here the runtime for the interpeter is here

what I learned while writing this project

Writing a programming languages is a whole lot of work. Doing a small programming language makes me appreciate the authors of the tools that i am using everyday. Someone who is implementing a language has to take care of all the detail, a programmer who is using that language is spared this effort, that's something to appreciate!

There is an awfull amount of detail hidden within a programming languages. Now this reminds me of the movies of Stanley Kubrick. Kubrick was obsessed with putting meaning into detail, i guess he would have liked the exercise of writing a programming language... (more info in this documentary )

Another thing: i am learning about interpreted languages (such as python, php, javascript, perl, etc...) Now I keep noticing quite a lot of details, while writing my little interpreter. I am keeping some notes here

The moral: you can learn a lot with this type of project! (i think the important part is to keep notes, otherwise you tend to forget the details...)