Move conversion code

 - Extract the doConversion helper from stattocsv/main.go over to
   convert.go so that it can be more easily be reused

cmd/stattocsv/main.go

@@ -6,93 +6,13 @@ package main
 // (e.g. it may be the number of days since January 1, 1960).
 
 import (
-	"encoding/csv"
 	"fmt"
-	"io"
 	"os"
 	"strings"
-	"time"
 
 	"github.com/dominodatalab/datareader"
 )
 
-func doConversion(rdr datareader.StatfileReader) {
-
-	w := csv.NewWriter(os.Stdout)
-
-	ncol := len(rdr.ColumnNames())
-	if err := w.Write(rdr.ColumnNames()); err != nil {
-		panic(err)
-	}
-
-	row := make([]string, ncol)
-
-	for {
-		chunk, err := rdr.Read(1000)
-		if err != nil && err != io.EOF {
-			panic(err)
-		} else if chunk == nil || err == io.EOF {
-			break
-		}
-
-		for j := 0; j < len(chunk); j++ {
-			chunk[j] = chunk[j].UpcastNumeric()
-		}
-
-		nrow := chunk[0].Length()
-
-		numbercols := make([][]float64, ncol)
-		stringcols := make([][]string, ncol)
-		timecols := make([][]time.Time, ncol)
-
-		missing := make([][]bool, ncol)
-
-		for j := 0; j < ncol; j++ {
-			missing[j] = chunk[j].Missing()
-			dcol := chunk[j].Data()
-			switch v := dcol.(type) {
-			case []time.Time:
-				timecols[j] = v
-			case []float64:
-				numbercols[j] = v
-			case []string:
-				stringcols[j] = v
-			default:
-				panic(fmt.Sprintf("unknown type: %T", dcol))
-			}
-		}
-
-		for i := range nrow {
-			for j := range ncol {
-				if numbercols[j] != nil {
-					if missing[j] == nil || !missing[j][i] {
-						row[j] = fmt.Sprintf("%f", numbercols[j][i])
-					} else {
-						row[j] = ""
-					}
-				} else if stringcols[j] != nil {
-					if missing[j] == nil || !missing[j][i] {
-						row[j] = stringcols[j][i]
-					} else {
-						row[j] = ""
-					}
-				} else if timecols[j] != nil {
-					if missing[j] == nil || !missing[j][i] {
-						row[j] = fmt.Sprintf("%v", timecols[j][i])
-					} else {
-						row[j] = ""
-					}
-				}
-			}
-			if err := w.Write(row); err != nil {
-				panic(err)
-			}
-		}
-	}
-
-	w.Flush()
-}
-
 func main() {
 
 	if len(os.Args) == 1 {
@@ -141,5 +61,5 @@ func main() {
 		rdr = stata
 	}
 
-	doConversion(rdr)
+	datareader.DoConversion(rdr)
 }

convert.go

@@ -0,0 +1,86 @@
+package datareader
+
+import (
+	"encoding/csv"
+	"fmt"
+	"io"
+	"os"
+	"time"
+)
+
+func DoConversion(rdr StatfileReader) {
+
+	w := csv.NewWriter(os.Stdout)
+
+	ncol := len(rdr.ColumnNames())
+	if err := w.Write(rdr.ColumnNames()); err != nil {
+		panic(err)
+	}
+
+	row := make([]string, ncol)
+
+	for {
+		chunk, err := rdr.Read(1000)
+		if err != nil && err != io.EOF {
+			panic(err)
+		} else if chunk == nil || err == io.EOF {
+			break
+		}
+
+		for j := 0; j < len(chunk); j++ {
+			chunk[j] = chunk[j].UpcastNumeric()
+		}
+
+		nrow := chunk[0].Length()
+
+		numbercols := make([][]float64, ncol)
+		stringcols := make([][]string, ncol)
+		timecols := make([][]time.Time, ncol)
+
+		missing := make([][]bool, ncol)
+
+		for j := 0; j < ncol; j++ {
+			missing[j] = chunk[j].Missing()
+			dcol := chunk[j].Data()
+			switch v := dcol.(type) {
+			case []time.Time:
+				timecols[j] = v
+			case []float64:
+				numbercols[j] = v
+			case []string:
+				stringcols[j] = v
+			default:
+				panic(fmt.Sprintf("unknown type: %T", dcol))
+			}
+		}
+
+		for i := range nrow {
+			for j := range ncol {
+				if numbercols[j] != nil {
+					if missing[j] == nil || !missing[j][i] {
+						row[j] = fmt.Sprintf("%f", numbercols[j][i])
+					} else {
+						row[j] = ""
+					}
+				} else if stringcols[j] != nil {
+					if missing[j] == nil || !missing[j][i] {
+						row[j] = stringcols[j][i]
+					} else {
+						row[j] = ""
+					}
+				} else if timecols[j] != nil {
+					if missing[j] == nil || !missing[j][i] {
+						row[j] = fmt.Sprintf("%v", timecols[j][i])
+					} else {
+						row[j] = ""
+					}
+				}
+			}
+			if err := w.Write(row); err != nil {
+				panic(err)
+			}
+		}
+	}
+
+	w.Flush()
+}