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op_concat.go
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op_concat.go
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package spruce
import (
"fmt"
"strings"
"github.com/starkandwayne/goutils/ansi"
"github.com/starkandwayne/goutils/tree"
. "github.com/geofffranks/spruce/log"
)
// ConcatOperator ...
type ConcatOperator struct{}
// Setup ...
func (ConcatOperator) Setup() error {
return nil
}
// Phase ...
func (ConcatOperator) Phase() OperatorPhase {
return EvalPhase
}
// Dependencies ...
func (ConcatOperator) Dependencies(_ *Evaluator, _ []*Expr, _ []*tree.Cursor, auto []*tree.Cursor) []*tree.Cursor {
return auto
}
// Run ...
func (ConcatOperator) Run(ev *Evaluator, args []*Expr) (*Response, error) {
DEBUG("running (( concat ... )) operation at $.%s", ev.Here)
defer DEBUG("done with (( concat ... )) operation at $%s\n", ev.Here)
var l []string
if len(args) < 2 {
return nil, fmt.Errorf("concat operator requires at least two arguments")
}
for i, arg := range args {
v, err := arg.Resolve(ev.Tree)
if err != nil {
DEBUG(" arg[%d]: failed to resolve expression to a concrete value", i)
DEBUG(" [%d]: error was: %s", i, err)
return nil, err
}
switch v.Type {
case Literal:
DEBUG(" arg[%d]: using string literal '%v'", i, v.Literal)
DEBUG(" [%d]: appending '%v' to resultant string", i, v.Literal)
l = append(l, fmt.Sprintf("%v", v.Literal))
case Reference:
DEBUG(" arg[%d]: trying to resolve reference $.%s", i, v.Reference)
s, err := v.Reference.Resolve(ev.Tree)
if err != nil {
DEBUG(" [%d]: resolution failed\n error: %s", i, err)
return nil, fmt.Errorf("Unable to resolve `%s`: %s", v.Reference, err)
}
switch s.(type) {
case map[interface{}]interface{}:
DEBUG(" arg[%d]: %v is not a string scalar", i, s)
return nil, ansi.Errorf("@R{tried to concat} @c{%s}@R{, which is not a string scalar}", v.Reference)
case []interface{}:
DEBUG(" arg[%d]: %v is not a string scalar", i, s)
return nil, ansi.Errorf("@R{tried to concat} @c{%s}@R{, which is not a string scalar}", v.Reference)
default:
DEBUG(" [%d]: appending '%s' to resultant string", i, s)
l = append(l, fmt.Sprintf("%v", s))
}
default:
DEBUG(" arg[%d]: I don't know what to do with '%v'", i, arg)
return nil, fmt.Errorf("concat operator only accepts string literals and key reference arguments")
}
DEBUG("")
}
final := strings.Join(l, "")
DEBUG(" resolved (( concat ... )) operation to the string:\n \"%s\"", final)
return &Response{
Type: Replace,
Value: final,
}, nil
}
func init() {
RegisterOp("concat", ConcatOperator{})
}