fileparsing.nim

## main.nim - uses a loop and a split
import strutils

let inFile = open("input.txt", fmRead)
let outFile = open("output.txt", fmWrite)

var ln: TaintedString = ""
var parts: seq[string]

while inFile.readLine(ln):
  parts = ln.split('\t')
  
  for idx, val in pairs(parts):
    parts[idx] &= "_mark"
  
  outFile.writeLine(parts.join(", "))

outFile.close()
inFile.close()

## main_sequtils.nim - uses sequtils
import strutils, sequtils

let inFile = open("input.txt", fmRead)
let outFile = open("output.txt", fmWrite)

var ln: TaintedString = ""

while inFile.readLine(ln):
  outFile.writeLine(map(ln.split('\t'), proc(x: string): string = x & "_mark").join(", "))

outFile.close()
inFile.close()

## main_lines.nim - uses the lines() proc
import strutils

let
    inFile = open("input.txt", fmRead)
    outFile = open("output.txt", fmWrite)

var parts: seq[string]

for ln in inFile.lines:
  parts = ln.split('\t')
  
  for idx, val in pairs(parts):
    parts[idx] &= "_mark"
  
  outFile.writeLine(parts.join(", "))

outFile.close()
inFile.close()


## main_streams.nim - uses the streams module
import strutils, streams

let
    inFile = newFileStream("input.txt", fmRead)
    outFile = open("output.txt", fmWrite)

var
    parts: seq[string]
    ln = ""

while inFile.readLine(ln):
  parts = ln.split('\t')
  
  for idx, val in pairs(parts):
    parts[idx] &= "_mark"
  
  outFile.writeLine(parts.join(", "))

outFile.close()
inFile.close()


## main_streams_sequtils - uses the streams module, with sequtils
import strutils, streams, sequtils

let
    inFile = newFileStream("input.txt", fmRead)
    outFile = open("output.txt", fmWrite)

var ln = ""

while inFile.readLine(ln):
  outFile.writeLine(map(ln.split('\t'), proc(x: string): string = x & "_mark").join(", "))

outFile.close()
inFile.close()

## Fast
import streams, parsecsv, strutils

proc main() =
  let
    fname = "input.txt"
    infile = newFileStream(fname, fmRead)
    outfile = open("output.txt", fmWrite)
  
  var
    vcf: CsvParser
  
  open(vcf, infile, fname, separator='\t')
  
  while readRow(vcf):
    for i, word in vcf.row:
      vcf.row[i] = word & "_mark"
    outfile.writeLine(join(vcf.row, ", "))

main()

### Stats 1GB
➜  test_nim_file time python3 ./main.py
python3 ./main.py  8.81s user 1.58s system 98% cpu 10.558 total
➜  test_nim_file time ./main
./main  3.76s user 1.50s system 96% cpu 5.451 total
➜  test_nim_file time ./main_sequtils
./main_sequtils  3.63s user 1.46s system 96% cpu 5.279 total
➜  test_nim_file time ./main_lines
./main_lines  3.98s user 1.49s system 98% cpu 5.572 total
➜  test_nim_file time ./main_streams
./main_streams  50.99s user 1.73s system 99% cpu 53.041 total
➜  test_nim_file time ./main_streams_sequtils
./main_streams_sequtils  50.95s user 1.73s system 99% cpu 53.002 total
➜  test_nim_file


### Stats 100MB
nim-parse:master$ make time
for b in nimer nvill nvill_unwrapped euant0 euant_lines euant_streams euant_sequtils euant_streams_sequtils; do echo $b; time -p ./$b; done
nimer
real 2.23
user 1.91
sys 0.30
nvill
real 1.92
user 1.60
sys 0.29
nvill_unwrapped
real 2.82
user 2.51
sys 0.29
euant0
real 2.14
user 1.77
sys 0.34
euant_lines
real 2.03
user 1.70
sys 0.30
euant_streams
real 8.28
user 7.94
sys 0.30
euant_sequtils
real 2.29
user 1.95
sys 0.32
euant_streams_sequtils
real 8.49
user 8.16
sys 0.30
time -p python2.7 quick.py
real         4.63
user         4.30
sys          0.30
time -p python3 quick.py
real         5.07
user         4.77
sys          0.24