cello

node-cello

a simple DSL to generate simple C programs

Alternative title:

A magical DSL to generate C code from CoffeeScript

Introduction

node-cello is a work-in-progress DSL and template engine for generating C programs.

Warning

This is an experimental project, and should be used with care.

For the moment only basic C code can be generated using this library.

The code is a bit messy, and architecture/syntax is not fixed yet.

However it is already on NPM repository because:

1. it basically works
2. it's a dependency of another project

Thank you for your understanding!

Documentation

Options

You can pass parameters to cello. For the moment only a few are supported:

• indent: the indentation string to use (eg. " " or "\t")
• debug: some debug messages - for development only
• evaluate: a func which return a list of JS references to interpret BEFORE code generation
• ignore: a func which return a list of JS references to ignore (won't be translated to C)

Example:

src = C(indent: "  ", debug: yes) -> 
  main = ->

Compiling

Experimental support of gcc is implemented:

{C, run} = require 'cello'
src = C -> main = -> printf "hello world"
run src, (output) -> console.log "output: #{output}"

Communicating

You can execute a program, and read/write from it, as it was a bi-directional stream:

{C, Program} = require 'cello'
src = C -> main = -> 
  # put code that reads from STDIN and write to
  # STDOUT here (see examples/pipeline.coffee)
program = new Program src
program.run process.argv[1..], ->
   
  # bind to output events
  program.on 'stdout', (buff)           -> console.log buff.toString()
  program.on 'stderr', (buff)           -> console.log buff.toString()
  program.on 'close',  ({code, signal}) -> console.log code   
 
  # do stuff
  program.write "hello world"
  program.close()

Demos

Demo 1

{ C, run } = require 'cello'
 
src = C ->
  include 'stdio.h'
  int x = 40
  main = ->
   int y = 43 + x
   printf "hello"
 
# compile & run 
run src, console.log

Will generate this code:

#include <stdio.h>
int x = 40;
int main() {
    int y = (43 + x);
    printf("hello");
    return 0;
}

Then it will run and print 'hello'. Magic? yes.

Demo 2

{C, run} = require 'cello'
 
options =
  indent: "  "
  evaluate: -> [ Math.random, Math.round ]
  ignore: -> []
  debug: no
 
src = C(options) -> 
  include 'stdio.h'
  include 'stdlib.h'
 
  int x = 40
 
  main = ->
 
    printf "hello, "
    int y = 43 + x / 10
    printf "result is %i", y
 
    int a = [ 0, 0, 0, 1, 0 ]
    int b[5] = [ 0 ]
 
    float seed = Math.round Math.random() * 1000
 
    #int compute = (a=int, b=int) -> a + b
 
    char p1 = 127
    char $p2 = malloc sizeof char
 
    int i = 0
    while i < 10000
      ++i
    while i > 10000
      i--   
 
    0 
 
    
 
console.log "#{src}"
 
run src, (err, output) ->
  if err
    throw new Error err
  else
    console.log "#{output}"

will generate:

#include <stdio.h>
#include <stdlib.h>
int x = 40;
int main() {
  printf("hello, ");
  int y = 43 + x / 10;
  printf("result is %i",y);
  int a = {0, 0, 0, 1, 0};
  int b[5] = {0};
  float seed = 926;
  char p1 = 127;
  char *p2 = malloc(sizeof(char));
  int i = 0;
  while (i < 10000) {
    ++i;
  }
  while (i > 10000) {
    i--;
  }
  return 0;
}
 

with output:

hello

Demo 3

This demo shows how to communicate with the sub C program:

{C, Program} = require 'cello'
 
program = new Program C() ->
  include 'stdio.h'
  int main = ->
    setbuf stdout, NULL
    char c = fgetc stdin
    while c isnt EOF
      printf "%c", c
      c = fgetc stdin
    0
 
# call the program, here with an empty argument list
program.run [], ->
  console.log "demo.program started"
  program.write "hello"
  program.write "world"
  program.close ({code, signal}) -> console.log "closed: #{code}"
 
program.on 'stdout',  (buff) ->  console.log "output: " + buff.toString()
program.on 'stderr',  (buff) ->  console.log "demo.stderr: " + buff.toString()

WISHLIST FOR SANTA

• support for inline C statements, as lone strings (eg. """(void *) i;""")
• support for Class: http://stackoverflow.com/a/840703
• support for new (either malloc, or just ignore it?, but at least it will feel a bit more natural)
• support for function pointers allocation
• support for &? (altough it's mostly used for func pointers, and it is implicit)
• find a more elegant solution than using 'Void' as alias of 'void'?
• find an elegant solution to support const (which is forbidden in Coffee/JavaScript)
• support typedef
• support struct
• add more doc (eg. the if / while example)
• support for loops (by not translating directly but generating boilerplate)
• support pointer casting
• Type inference (eg. that "i = 0" will convert to "int i = 0")
• Implement ALL C language features
• more unit tests
• more CoffeeScript magic (eg. doing more implicit stuff such as: x = y for x in [0...2])

Changelog

0.1.1

• just fixed typo and the doc, to have a better page on NPM's website

0.1.0

• added a new Program class
• support for bi-directional communication using unix pipes

0.0.9 - unreleased

0.0.8 - unreleased

• Support for include 'test.h' and include '<stdlib.h>'

0.0.7

• Added support for break and continue
• added support for functions (eg. main) args
• added support for command line args (when calling run())

0.0.6

• fixed a bug with missing parameters in the options
• Added support for "if" expressiion
• Simplified "while" expression
• Support for blocks "{}"
• Added basic unit tests

0.0.5

• Rewrote nearly everything from scratch
• should be f***ing more robust now
• moved debug scripts to /examples
• experimenting with OpenCL kernel generation (yeah for node-evolve!)

0.0.4

Added basic support for:

• array declaration and initialization
• pointers (using $ instead of *)
• while loops

Also fixed a few bugs around

0.0.3

• basic support for gcc compilation and execution

0.0.2

• added some options

0.0.1

• Removed debug console.logs
• forgot to add uglify-js as dependency in the package.json!
• removed useless dependencies in code

0.0.0

• Basic features are supported