Files and Text Streams

Parse Records

Parse short record text and total a numeric field.

parse-records Text records can be parsed with small, bounded loops.

Parse Records

bonus
ParseRecords.kt
Replay: real traced execution (multi-file project)
fun main() {
    val records = "tea:2;rice:3"
    val bonus = 0
    val rows = records.split(";")
    var total = bonus
    var names = ""

    for (row in rows) {
        val fields = row.split(":")
        val name = fields[0]
        val count = fields[1].toInt()
        total += count
        names += name
    }

    println("bonus=$bonus")
    println("rows=${rows.size}")
    println("total=$total")
    println("names=$names")
}

fun main() {
    val records = "tea:2;rice:3"
    val bonus = 1
    val rows = records.split(";")
    var total = bonus
    var names = ""

    for (row in rows) {
        val fields = row.split(":")
        val name = fields[0]
        val count = fields[1].toInt()
        total += count
        names += name
    }

    println("bonus=$bonus")
    println("rows=${rows.size}")
    println("total=$total")
    println("names=$names")
}

fun main() {
    val records = "tea:2;rice:3"
    val bonus = 5
    val rows = records.split(";")
    var total = bonus
    var names = ""

    for (row in rows) {
        val fields = row.split(":")
        val name = fields[0]
        val count = fields[1].toInt()
        total += count
        names += name
    }

    println("bonus=$bonus")
    println("rows=${rows.size}")
    println("total=$total")
    println("names=$names")
}

  1. records ← tea:2;rice:3, bonus ← 0, rows ← [tea:2, rice:3], total ← 0

    1fun main() {2    val records→ tea:2;rice:3 = "tea:2;rice:3"3    val bonus→ 0 = 0 //@bonus=1, 54    val rows→ [tea:2, rice:3] = recordstea:2;rice:3.split(";")5    var total→ 0 = bonus06    var names→ (empty) = ""

  2. fields ← [tea, 2], name ← tea, count ← 2, total ← 2, names ← tea

    pass 1 of 2
    8for (rowtea:2 in rows[tea:2, rice:3]) {9    val fields→ [tea, 2] = rowtea:2.split(":")10    val name→ tea = fields[0]tea11    val count→ 2 = fields[1]2.toInt()12    total→ 2 += count213    names→ tea += nametea14}

  3. fields ← [rice, 3], name ← rice, count ← 3, total ← 5, names ← tearice

    pass 2 of 2
    8for (rowrice:3 in rows[tea:2, rice:3]) {9    val fields→ [rice, 3] = rowrice:3.split(":")10    val name→ rice = fields[0]rice11    val count→ 3 = fields[1]3.toInt()12    total→ 5 += count313    names→ tearice += namerice14}

  4. println("bonus=$bonus")

    16    println("bonus=$bonus0")17    println("rows=${rows.size2}")18    println("total=$total5")19    println("names=$namestearice")20}
    outputbonus=0
rows=2
total=5
names=tearice
    values this step[tea:2, rice:3]rows

  1. records ← tea:2;rice:3, bonus ← 1, rows ← [tea:2, rice:3], total ← 1

    1fun main() {2    val records→ tea:2;rice:3 = "tea:2;rice:3"3    val bonus→ 1 = 14    val rows→ [tea:2, rice:3] = recordstea:2;rice:3.split(";")5    var total→ 1 = bonus16    var names→ (empty) = ""

  2. fields ← [tea, 2], name ← tea, count ← 2, total ← 3, names ← tea

    pass 1 of 2
    8for (rowtea:2 in rows[tea:2, rice:3]) {9    val fields→ [tea, 2] = rowtea:2.split(":")10    val name→ tea = fields[0]tea11    val count→ 2 = fields[1]2.toInt()12    total→ 3 += count213    names→ tea += nametea14}

  3. fields ← [rice, 3], name ← rice, count ← 3, total ← 6, names ← tearice

    pass 2 of 2
    8for (rowrice:3 in rows[tea:2, rice:3]) {9    val fields→ [rice, 3] = rowrice:3.split(":")10    val name→ rice = fields[0]rice11    val count→ 3 = fields[1]3.toInt()12    total→ 6 += count313    names→ tearice += namerice14}

  4. println("bonus=$bonus")

    16    println("bonus=$bonus1")17    println("rows=${rows.size2}")18    println("total=$total6")19    println("names=$namestearice")20}
    outputbonus=1
rows=2
total=6
names=tearice
    values this step[tea:2, rice:3]rows

  1. records ← tea:2;rice:3, bonus ← 5, rows ← [tea:2, rice:3], total ← 5

    1fun main() {2    val records→ tea:2;rice:3 = "tea:2;rice:3"3    val bonus→ 5 = 54    val rows→ [tea:2, rice:3] = recordstea:2;rice:3.split(";")5    var total→ 5 = bonus56    var names→ (empty) = ""

  2. fields ← [tea, 2], name ← tea, count ← 2, total ← 7, names ← tea

    pass 1 of 2
    8for (rowtea:2 in rows[tea:2, rice:3]) {9    val fields→ [tea, 2] = rowtea:2.split(":")10    val name→ tea = fields[0]tea11    val count→ 2 = fields[1]2.toInt()12    total→ 7 += count213    names→ tea += nametea14}

  3. fields ← [rice, 3], name ← rice, count ← 3, total ← 10, names ← tearice

    pass 2 of 2
    8for (rowrice:3 in rows[tea:2, rice:3]) {9    val fields→ [rice, 3] = rowrice:3.split(":")10    val name→ rice = fields[0]rice11    val count→ 3 = fields[1]3.toInt()12    total→ 10 += count313    names→ tearice += namerice14}

  4. println("bonus=$bonus")

    16    println("bonus=$bonus5")17    println("rows=${rows.size2}")18    println("total=$total10")19    println("names=$namestearice")20}
    outputbonus=5
rows=2
total=10
names=tearice
    values this step[tea:2, rice:3]rows