In bioinformatics, long character strings are often encoded in a format called FASTA.

A FASTA file can contain several strings, each identified by a name marked by a > (greater than) character at the beginning of the line.



Task

Write a program that reads a FASTA file such as:

>Rosetta_Example_1
THERECANBENOSPACE
>Rosetta_Example_2
THERECANBESEVERAL
LINESBUTTHEYALLMUST
BECONCATENATED


Output:
Rosetta_Example_1: THERECANBENOSPACE
Rosetta_Example_2: THERECANBESEVERALLINESBUTTHEYALLMUSTBECONCATENATED

Note that a high-quality implementation will not hold the entire file in memory at once; real FASTA files can be multiple gigabytes in size.




 
import strutils
 
let input = """>Rosetta_Example_1
    THERECANBENOSPACE
    >Rosetta_Example_2
    THERECANBESEVERAL
    LINESBUTTHEYALLMUST
    BECONCATENATED""".unindent
 
proc fasta*(input: string) =
    var row = ""
    for line in input.splitLines:
        if line.startsWith(">"):
            if row != "": echo row
            row = line[1..^1] & ": "
        else:
            row &= line.strip
    echo row
 
fasta(input)
 