activity/tools/exp/rdf/parse.go
Cory Slep 0470f8e603 Add internal parsed RDF definition data types.
This is an evolution of the old tools/defs/types.go file which
essentially had these data structs manually defined in a static go file.
Now, the parser should be able to construct this data structure on the
fly from input files and reference files.
2018-11-28 23:50:07 +01:00

100 行
2.7 KiB
Go

package rdf
import (
"fmt"
)
const (
JSON_LD_CONTEXT = "@context"
)
// JSONLD is an alias for the generic map of keys to interfaces, presumably
// parsed from a JSON-encoded context definition file.
type JSONLD map[string]interface{}
// RDFNode is able to operate on a specific key if it applies towards its
// ontology (determined at creation time). It applies the value in its own
// specific implementation on the context.
type RDFNode interface {
Apply(key string, value interface{}, ctx ParseContext) (bool, error)
}
// ParseJSONLDContext implements a super basic JSON-LD @context parsing
// algorithm in order to build a tree that can parse the rest of the document.
func ParseJSONLDContext(registry *RDFRegistry, input JSONLD) (nodes []RDFNode, err error) {
i, ok := input[JSON_LD_CONTEXT]
if !ok {
err = fmt.Errorf("no @context in input")
return
}
if inArray, ok := i.([]interface{}); ok {
// @context is an array
for _, iVal := range inArray {
if valMap, ok := iVal.(map[string]interface{}); ok {
// Element is a JSON Object (dictionary)
for alias, val := range valMap {
if s, ok := val.(string); ok {
var n []RDFNode
n, err = registry.getAliased(alias, s)
if err != nil {
return
}
nodes = append(nodes, n...)
} else if aliasedMap, ok := val.(map[string]interface{}); ok {
var n []RDFNode
n, err = registry.getAliasedObject(alias, aliasedMap)
if err != nil {
return
}
nodes = append(nodes, n...)
} else {
err = fmt.Errorf("@context value in dict in array is neither a dict nor a string")
return
}
}
} else if s, ok := iVal.(string); ok {
// Element is a single value
var n []RDFNode
n, err = registry.getFor(s)
if err != nil {
return
}
nodes = append(nodes, n...)
} else {
err = fmt.Errorf("@context value in array is neither a dict nor a string")
return
}
}
} else if inMap, ok := i.(map[string]interface{}); ok {
// @context is a JSON object (dictionary)
for alias, iVal := range inMap {
if s, ok := iVal.(string); ok {
var n []RDFNode
n, err = registry.getAliased(alias, s)
if err != nil {
return
}
nodes = append(nodes, n...)
} else if aliasedMap, ok := iVal.(map[string]interface{}); ok {
var n []RDFNode
n, err = registry.getAliasedObject(alias, aliasedMap)
if err != nil {
return
}
nodes = append(nodes, n...)
} else {
err = fmt.Errorf("@context value in dict is neither a dict nor a string")
return
}
}
} else {
// @context is a single value
s, ok := i.(string)
if !ok {
err = fmt.Errorf("single @context value is not a string")
}
return registry.getFor(s)
}
return
}