Added new recipe

pkg/yqlib/doc/usage/recipes.md

@@ -117,7 +117,7 @@ myArray:
 - So, we use `|=` to update `.myArray`. This is the same as doing `.myArray = (.myArray | sort_by(.numBuckets))`
 
 ## Filter, flatten, sort and unique
-Lets
+Lets find the unique set of names from the document.
 
 Given a sample.yml file of:
 ```yaml
@@ -153,3 +153,35 @@ will output
 - Next we pipe `|` that through `sort` and then `unique` to get a sorted, unique list of the names!
 - See the [flatten](https://mikefarah.gitbook.io/yq/operators/flatten), [sort](https://mikefarah.gitbook.io/yq/operators/sort) and [unique](https://mikefarah.gitbook.io/yq/operators/unique) for more information and examples.
 
+## Export as environment variables (script), or any custom format
+Given a yaml document, lets output a script that will configure environment variables with that data. This same approach can be used for exporting into custom formats.
+
+Given a sample.yml file of:
+```yaml
+var0: string0
+var1: string1
+ary0:
+  - aryval0
+  - aryval1
+  - aryval2
+```
+then
+```bash
+yq '.[] |(
+	( select(kind == "scalar") | key + "='" + . + "'"),
+	( select(kind == "seq") | key + "=(" + (map("'" + . + "'") | join(",")) + ")")
+)' sample.yml
+```
+will output
+```yaml
+var0='string0'
+var1='string1'
+ary0=('aryval0','aryval1','aryval2')
+```
+
+### Explanation:
+- `.[]` matches all top level elements
+- We need a string expression for each of the different types that will product the bash syntax, we'll use the union operator , to join them together
+- Scalars, we just need the key and quoted value: `( select(kind == "scalar") | key + "='" + . + "'")`
+- Sequences (or arrays) are trickier, we need to quote each value and `join` them with `,`: `map("'" + . + "'") | join(",")`
+

pkg/yqlib/recipes_test.go

@@ -4,6 +4,11 @@ import (
 	"testing"
 )
 
+var bashEnvScript = `.[] |(
+	( select(kind == "scalar") | key + "='" + . + "'"),
+	( select(kind == "seq") | key + "=(" + (map("'" + . + "'") | join(",")) + ")")
+)`
+
 var recipes = []expressionScenario{
 	{
 		description:    "Find items in an array",
@@ -66,7 +71,7 @@ var recipes = []expressionScenario{
 	},
 	{
 		description:    "Filter, flatten, sort and unique",
-		subdescription: "Lets",
+		subdescription: "Lets find the unique set of names from the document.",
 		document:       `[{type: foo, names: [Fred, Catherine]}, {type: bar, names: [Zelda]}, {type: foo, names: Fred}, {type: foo, names: Ava}]`,
 		expression:     `[.[] | select(.type == "foo") | .names] | flatten | sort | unique`,
 		explanation: []string{
@@ -82,6 +87,23 @@ var recipes = []expressionScenario{
 			"D0, P[], (!!seq)::- Ava\n- Catherine\n- Fred\n",
 		},
 	},
+	{
+		description:    "Export as environment variables (script), or any custom format",
+		subdescription: "Given a yaml document, lets output a script that will configure environment variables with that data. This same approach can be used for exporting into custom formats.",
+		document:       "var0: string0\nvar1: string1\nary0: [aryval0, aryval1, aryval2]\n",
+		expression:     bashEnvScript,
+		expected: []string{
+			"D0, P[var0='string0'], (!!str)::var0='string0'\n",
+			"D0, P[var1='string1'], (!!str)::var1='string1'\n",
+			"D0, P[ary0=('aryval0','aryval1','aryval2')], (!!str)::ary0=('aryval0','aryval1','aryval2')\n",
+		},
+		explanation: []string{
+			"`.[]` matches all top level elements",
+			"We need a string expression for each of the different types that will product the bash syntax, we'll use the union operator , to join them together",
+			"Scalars, we just need the key and quoted value: `( select(kind == \"scalar\") | key + \"='\" + . + \"'\")`",
+			"Sequences (or arrays) are trickier, we need to quote each value and `join` them with `,`: `map(\"'\" + . + \"'\") | join(\",\")`",
+		},
+	},
 }
 
 func TestRecipes(t *testing.T) {