README
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📺 go-pic
COBOL PIC (Picture) clause parsing library
🤷🏽 What is go-pic
gopic is both a tool and package, it's purpose is to help you process COBOL copybook files with ease
📤 Unmarshaller
gopic can be used to enable simpler 1:1 mapping of PIC definitions to Go structs.
Simply open your data file and pass it to a gopic decoder with the struct that represents the source copybook
Show usage
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Import gopic
import ( pic "github.com/foundatn-io/go-pic" ) -
Tag your structs
Say your copybook data looks like
000180 15 PropertyA PIC X(5). 00000117 000190 15 PropertyB PIC X(2). 00000118You would tag your struct like so
type yourStruct struct { PropertyA string `pic:"5"` PropertyB string `pic:"2"` } -
Prepare a decoder and unmarshal your input
d := pic.NewDecoder(f) // where f is your io.Reader / data typ := yourStruct{} // with pic tags if err := d.Decode(typ); err != nil { log.Fatal(err) }
📥 Struct generator
gopic can be used to generate simpler 1:1 mapping of PIC definitions to Go structs.
gopic provides support to generate flattened Go struct representations of your COBOL copybooks, tagged with length statements and assigned the appropriate type for unmarshalling files that match your COBOL copybook definitions, so you need not manually create or tag your structs when using go-pic for unmarshalling.
Show usage
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Install gopic!
Get started using
gopicby for struct generation by running:git clone github.com/foundatn-io/go-pic cd go-pic make install -
Generate structs from a copybook file (long-form flags)
gopic file --package=shipping --output=shipping --input=cobolstuff/copybook-shipping.txt -
Generate many structs from a directory containing only copybooks (short-form flags)
gopic dir -p mystructsdir -o mystructsdir -i cobolstuff
When using gopic for struct generation, additional, non-functional values are tagged to the PIC tags, for legibility's sake.
For example, the example copybook clauses:
000180 15 PropertyA PIC 9(5). 00000117
000190 15 PropertyB PIC X(2). 00000118
if generated with gopic becomes:
type Copybook struct{
PropertyA uint `pic:"9"` // start:1 end:9
PropertyB string `pic:"2"` // start:10 end:11
}
🚧 Alas, these are not yet supported
- PIC symbols [
S,V,P] - Level indicator 88 enums are skipped
- Level indicator 77 items which cannot be sub-divided
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrNilPointer = errors.New("decode: unmarshal target object is nil")
ErrNilPointer is returned when the target object is nil.
var ErrNotAPointer = errors.New("decode: unmarshal target object is not a pointer")
ErrNotAPointer is returned when the target object is not a pointer.
Functions ¶
Types ¶
type Decoder ¶
type Decoder interface {
Decode(interface{}) error
}
Decoder ...
func NewDecoder ¶
NewDecoder builds a new decoder using a bufio.Scanner for the given input io.Reader.
type UnmarshalTypeError ¶
type UnmarshalTypeError struct {
Value string // raw value
Type reflect.Type // type of Go value it could not be assigned to
Struct string // name of the struct type containing the field
Field string // name of the field holding the Go value
Cause error // original error
}
UnmarshalTypeError represents an unmarshal malfunction
func (*UnmarshalTypeError) Error ¶
func (e *UnmarshalTypeError) Error() string
Error converts details of an UnmarshalTypeError into a meaningful string
Source Files
Directories