From c4e9516aa64361c34706f5040ec86e3d8ba93d17 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Mon, 13 May 2019 09:32:08 +1000
Subject: [PATCH] Prefix matching splat

Fixes https://github.com/mikefarah/yq/issues/218
---
 data_navigator.go      | 14 ++++++++++++--
 data_navigator_test.go | 18 ++++++++++++++----
 examples/data3.yaml    | 15 ++++++++++++++-
 3 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/data_navigator.go b/data_navigator.go
index d4548e6..93d2a13 100644
--- a/data_navigator.go
+++ b/data_navigator.go
@@ -4,15 +4,25 @@ import (
 	"fmt"
 	"reflect"
 	"strconv"
+	"strings"
 
 	yaml "gopkg.in/mikefarah/yaml.v2"
 )
 
-func entriesInSlice(context yaml.MapSlice, key interface{}) []*yaml.MapItem {
+func matchesKey(key string, actual interface{}) bool {
+	var actualString = fmt.Sprintf("%v", actual)
+	var prefixMatch = strings.TrimSuffix(key, "*")
+	if prefixMatch != key {
+		return strings.HasPrefix(actualString, prefixMatch)
+	}
+	return actualString == key
+}
+
+func entriesInSlice(context yaml.MapSlice, key string) []*yaml.MapItem {
 	var matches = make([]*yaml.MapItem, 0)
 	for idx := range context {
 		var entry = &context[idx]
-		if key == "*" || fmt.Sprintf("%v", entry.Key) == key {
+		if matchesKey(key, entry.Key) {
 			matches = append(matches, entry)
 		}
 	}
diff --git a/data_navigator_test.go b/data_navigator_test.go
index f14d561..873ff3e 100644
--- a/data_navigator_test.go
+++ b/data_navigator_test.go
@@ -31,12 +31,22 @@ func TestReadMap_splat(t *testing.T) {
 mapSplat:
   item1: things
   item2: whatever
+  otherThing: cat
 `)
 	res, _ := readMap(data, "mapSplat", []string{"*"})
-	result := res.([]interface{})
-	var actual = []string{result[0].(string), result[1].(string)}
-	sort.Strings(actual)
-	assertResult(t, "[things whatever]", fmt.Sprintf("%v", actual))
+	assertResult(t, "[things whatever cat]", fmt.Sprintf("%v", res))
+}
+
+func TestReadMap_prefixSplat(t *testing.T) {
+	var data = parseData(`
+---
+mapSplat:
+  item1: things
+  item2: whatever
+  otherThing: cat
+`)
+	res, _ := readMap(data, "mapSplat", []string{"item*"})
+	assertResult(t, "[things whatever]", fmt.Sprintf("%v", res))
 }
 
 func TestReadMap_deep_splat(t *testing.T) {
diff --git a/examples/data3.yaml b/examples/data3.yaml
index fbe63d8..0aba4f1 100644
--- a/examples/data3.yaml
+++ b/examples/data3.yaml
@@ -1 +1,14 @@
-b: dog
\ No newline at end of file
+deep1:
+   hostA:
+      value: 1234
+   notRelevant:
+      value: bananas
+   hostB:
+      value: 5678
+deep2:
+   hostC:
+      value: 1234
+   notRelevant:
+      value: bananas
+   hostD:
+      value: 5678