GoFixedLength

Go library to deal with extracting fixed field form values using struct tags.

##Quickstart

Unmarshal unmarshals string data into an annotated interface. This should resemble:

type SomeType struct {
	DateField   time.Time `fixed:"0-8,20060102"` // Standard Go time formatting
	StringAfter string    `fixed:"8-15"`
	SomeFloat   float64   `fixed:"15-25,4"`      // Four decimals
}

var out SomeType
err := Unmarshal("20150202well   00012.1864", &out)

Marshal marshals struct data into a fixed-lenght formatted string.

type SomeType struct {
	ValA string        `fixed:"0-10"`
	ValB int           `fixed:"10-20"`
	ValC time.Time     `fixed:"20-30,2006-01-02"` // Standard Go time formatting
	ValD float64       `fixed:"30-40,3"`          // Three decimals
}

myStruct := SomeType{
	"this",
	12345,
	time.Now(),
	123.1234,
}

out, err := gofixedlength.Marshal(myStruct)
// out == "this      00000123452015-01-14000123.123"

Offsets are zero based.
Field filling is based on data type: for text types it will be spaces, while numbers will be right-aligned and filled with zeroes.
Floating-point values are printed with the specified number of decimals (two by default).
time.Time fields are printed with the specified layout.

String offsets are zero based.

##European-styled numbers To parse documents that use comma "," as decimal separator, just set to true the global variable:

func init() {
	gofixedlength.DECIMAL_COMMA = true
}

GoFixedLength is based on @jbuchbinder's Gofixedfield.