node-bash

node-bash is an interpreted language written using JavaScript.

Features

1. dynamic typing [ courtsey of JS ].
2. if, if else, while control structures.
3. functions. [ recursion is also supported ]
4. piping similar to bash.

Requirements

To run the language, you must need nodejs.

Usage

you can run scripts by executing following script. node node-bash.js < filename >

Tutorial

Keywords and special character used by the language

and, not, or, if, else, while, funct, |, =, <, >, <=, >=, !=, ==

Variable Creation

simple assignment will create variable in the current scope if does not exist.

a = 10;
#or
a = "Hello world";
#or
a = 1 + 2;

Operators

The language supports following operations.

1. addition ( + )
2. subtraction ( - )
3. multiplication ( * ) and division ( / )
4. power ( ^ )
5. boolean operations using >, <, <=, >=, !=, ==, and, not, or.
6. function call
7. piping ( | )

Function Definition

you can define a function using funct keyword.

funct main(){
  print( "Hello world" );
}

Piping

You can use piping similar to unix piping to pass output of one expression to other.

a = "Good morning";
a | b;
print( b );
#or
funct generateData(){
  pipe( "This is node-bash lang" );
}
generateData() | a;
print(a);

source of the pipe statement must be an expression or anything which generates a value but the destination must always be a variable or a function call. Functions can pipe data using pipe built in function.

BuiltIn functions

Following are the builtin functions supported by the languge.

1. print( data );
2. extractString( src, string_to_be_extracted ); # returns a string.
3. split( delim );
4. index( array, index ); # returns element at the given index.
5. len( array ) # returns the length of the array.

Examples

Fibonacci series Recursively

funct fibo( n ){
    if( n == 0 ){
        return 0;
    }
    if( n == 1 ){
        return 1;
    }
    else{
        return fibo( n - 2 ) + fibo( n - 1 );
    }
}
print( fibo(8) );

Simple arithmatic expressions

# addition
a = 1 + 2; 
# multiplication
a = 1 * 2 * 4;
#division
a = 4 / 2;
# exponantiation
a = 4 ^ 2;
# subtraction
a = 4 - 2;

Piping

funct getData(){
    pipe( "Good Morning" );
    pipe( "Bad Morning" );
    pipe( "Hello Good Morning" );
}

funct filter( out ){
    lines = split( out, "\n" );
    i = 0;
    length = len( lines );
    while( i < length ){
        data = extractString( index( lines, i ), "Good" );
        if( data == "Good" ){
            pipe( index( lines, i ) );
        }
        i = i + 1;
    }
}

getData() | filter() | output;
print( output );