JSPM

pyx scripting language

This is 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

/You might consider to sponsor this project via github sponsors/

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!

For example there is great deal of effort that goes into having half way readable error messages during parsing...

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...)