util.go

package cwl

import (
	"fmt"
	"github.com/commondream/yamlast"
	"github.com/kr/pretty"
	"os"
	"strings"
)

// errf makes fmt.Errorf shorter
func errf(msg string, args ...interface{}) error {
	return fmt.Errorf(msg, args...)
}

func debug(i ...interface{}) {
	pretty.Println(i...)
}

// for brevity
type node *yamlast.Node

// used for debugging
func fmtNode(n *yamlast.Node, indent string) string {
	kind := "Unknown"
	switch n.Kind {
	case yamlast.DocumentNode:
		kind = "Document"
	case yamlast.AliasNode:
		kind = "Alias"
	case yamlast.MappingNode:
		kind = "Mapping"
	case yamlast.SequenceNode:
		kind = "Sequence"
	case yamlast.ScalarNode:
		kind = "Scalar"
	}
	return fmt.Sprintf("%-30s Line/col: %3d %3d %40q",
		indent+kind, n.Line+1, n.Column, n.Value) //, n.Implicit)
}

// Dump the YAML tree for debugging.
func dump(n *yamlast.Node, indent string) {
	fmt.Fprintf(os.Stderr, "%s\n", fmtNode(n, indent))
	for _, c := range n.Children {
		dump(c, indent+"  ")
	}
}

// used for finding a value such as "class: Workflow" in a YAML mapping,
// which is needed before document processing can begin.
func findValue(n node, key string) (node, bool) {
	if n.Kind != yamlast.MappingNode {
		panic("findValue requires a mapping node")
	}
	for i := 0; i < len(n.Children)-1; i += 2 {
		k := n.Children[i]
		v := n.Children[i+1]
		if strings.ToLower(k.Value) == strings.ToLower(key) {
			return v, true
		}
	}
	return nil, false
}

func findKey(n node, key string) string {
	if v, ok := findValue(n, key); ok {
		return v.Value
	}
	return ""
}

type mapitem struct {
	k string
	v node
}

// itermap turns a YAML mapping into a slice of key/value pairs.
// a YAML mapping is a slice of [key1, value1, key2, value2, etc...]
func itermap(n node) []mapitem {
	items := []mapitem{}
	if n.Kind != yamlast.MappingNode {
		panic("expected mapping node")
	}
	for i := 0; i < len(n.Children)-1; i += 2 {
		k := n.Children[i]
		v := n.Children[i+1]
		items = append(items, mapitem{k.Value, v})
	}
	return items
}