Broccoli

Broccoli is a stack-based, semi-concatenative programming language.

You can try the JS interpreter at this address.

Overview

Hello world example:
```
"Hello World!" output
```
All operators have the same precedence. Computations are carried left to right. The below code prints 18, not 12:
```
3 + 3 * 3 output
```

Factorial computer:

input number = a
1 = b

{ a * b = b a - 1 = a }
{ a > 0 }
while

b output

Truth machine:

{ { 1 stdout .write } { true } while }
{ 0 output }
input number == 1
if

Copy input on output until an empty line is met or until the input ends:
```
input
{ output input }
{ = a a a }
while
```
Copy input on output (cat program):
```
stdin .read
stdout .write
```
Running a code block with run:
```
{ input output } = copy
copy run
```

Creating and invoking a function:

{ "Hello world!" output } : hello
hello

Control flow

Broccoli does not have keywords, but has predefined variables that can be used for codeflow instead.

Predefined variables

Broccoli features the following predefined variables:

if
- pop three values from the stack: <codeblock if yes> <codeblock if no> <boolean> if
while
- pop two codeblocks from the stack: <body codeblock> <test codeblock> while
printstack
- stringify and output the stack. It is meant to be used for debugging.
true
- push the boolean value true on the stack
false
- push the boolean value false on the stack
run
- pop a codeblock from the stack and run it in the current frame
eval
- pop a string from the stack, parse it and run it in the current frame
input
- read a line from the stdin, removing the newline at the end
number
- convert a scalar value to a number
output
- prints a scalar value to stdout (without appending newline)

Nearly grammar for broccoli

braced[X] -> "{" $X "}"
parenthesized[X] -> "(" $X ")"

main -> _ program _

program -> (expression (__ expression):*):?

expression -> identifier | string | number | operation | assignment | functionassignment | codeblock | group

identifier -> [A-Za-z_] [0-9A-Za-z_]:*

access -> "." identifier

string -> "\"" string_content:* "\""

string_content -> [^"\n\\] | "\\" .

number -> [1-9] [0-9]:*

operation -> operator __ expression

operator -> "==" | "!=" | "<=" | ">=" | "<<" | ">>" | [-+*/%<>&^|]

assignment -> "=" _ identifier

functionassignment -> ":" _ identifier

codeblock -> braced[_ program _]

group -> parenthesized[_ program _]

_  -> [ \t\n]:* (comment [ \t\n]:*):?
__ -> [ \t\n]:+ (comment [ \t\n]:*):* | (comment [ \t\n]:*):+

comment -> "#" .:* "\n"

Also see grammar.ne

Develop

git clone https://github.com/mathieucaroff/broccoli
# or git clone https://github.com/mathieucaroff/broccoli.git

cd broccoli

yarn install
# or npm install

yarn serve
# or npm run serve

Run the test

To test the parser, run yarn parcel test/parser/test.html and open the given given link.

To test the code samples, run yarn parcel test/runner/test.html and open the given link.

mathieucaroff / broccoli