How to read streams

Building a reader

The basic idea of readers is that they will consume chunks of input until they have consumed all which they desire, at which point they will return the consumed input and any data it has leftover. If the Reader does not consume all the data it needs it is expected to return a new reader that will.

These readers are fed data by streams... more coming soon.

Example

// will read till it has consumed the character given.
function readTillChar (chr) {                                                                
  function aux(queue, chunk) {                                                               
    if (chunk.data().indexOf(chr) != -1) {                                                   
      var a = chunk.data().slice(0, chunk.data().indexOf(chr));                              
      var b = chunk.data().slice(chunk.data().indexOf(chr)+1);                               
      return Application.Enough(queue + a, b);                                               
    } else {                                                                                 
      return Application.Partial(aux.curry(queue + chunk.data()));                           
    }                                                                                        
  }                                                                                          
  return Application.Partial(aux.curry(""));                                                 
}                                                                                            

// Uses the above stream reader....
                                                                
var stdin = process.openStdin();                                                             
var stream = new StreamIterator(stdin);                                                      
                                                                                             
console.log("Please enter a number: ");                                                      
stream.run(readTillChar("\n"), function getN (input, stream){                                
  var total = parseInt(input);                                                               
  if (total) {                                                                               
    console.log("You gave me: " + input + " I will read that many lines.");                  
    aux(0);                                                                                  
  } else {                                                                                   
    console.log("You must enter a number!");                                                 
    stream.run(readTillChar("\n"), getN);                                                    
  }                                                                                          
  function aux(n) {                                                                          
    stream.run(readTillChar("\n"), function(input, stream) {                                 
      console.log((n + 1) + ". " + input);                                                   
      if (n < total-1) {                                                                     
        aux(n+1);                                                                            
      } else {                                                                               
        console.log("Done");                                                                 
        console.log("Now enter your first, middle and last name (press enter after each)."); 
        stream.run(readTillChar("\n"), function(first) {                                     
          stream.run(readTillChar("\n"), function(middle) {                                  
            stream.run(readTillChar("\n"), function(last) {                                  
              console.log("First: " + first + "\nMidding: " + middle + "\nLast: " + last);   
              stdin.destroy();                                                               
            });                                                                              
          });                                                                                
        });                                                                                  
      }                                                                                      
    });                                                                                      
  }                                                                                          
});