Updating docs for v4.19.1 release

usage/convert.md

@@ -4,6 +4,12 @@ Encode and decode to and from JSON. Note that YAML is a _superset_ of JSON - so
 
 This means you don't need to 'convert' a JSON file to YAML - however if you want idiomatic YAML styling, then you can use the `-P/--prettyPrint` flag, see examples below.
 
+{% hint style="warning" %}
+Note that versions prior to 4.18 require the 'eval/e' command to be specified. 
+
+`yq e <exp> <file>`
+{% endhint %}
+
 ## Parse json: simple
 JSON is a subset of yaml, so all you need to do is prettify the output
 

usage/properties.md

@@ -1,11 +1,19 @@
-# Working with Properties
+# Properties
 
-## Yaml to Properties
+Encode to a property file (decode not yet supported). Line comments on value nodes will be copied across.
 
-To convert to property file format, use `--outputformat=props` or `-o=p`. Porting the comments from the `yaml` file to the property file is still in progress, currently line comments on the node values will be copied across. 
+By default, empty maps and arrays are not encoded - see below for an example on how to encode a value for these.
 
-Given a sample file of:
+{% hint style="warning" %}
+Note that versions prior to 4.18 require the 'eval/e' command to be specified. 
 
+`yq e <exp> <file>`
+{% endhint %}
+
+## Encode properties
+Note that empty arrays and maps are not encoded by default.
+
+Given a sample.yml file of:
 ```yaml
 # block comments don't come through
 person: # neither do comments on maps
@@ -13,17 +21,16 @@ person: # neither do comments on maps
     pets: 
     - cat # comments on array values appear
     food: [pizza] # comments on arrays do not
-```
+emptyArray: []
+emptyMap: []
 
+```
 then
-
 ```bash
-yq -o=p sample.yaml
-```
-
-will output:
-
+yq -o=props -I=0 '.' sample.yml
 ```
+will output
+```properties
 # comments on values appear
 person.name = Mike
 
@@ -32,3 +39,58 @@ person.pets.0 = cat
 person.food.0 = pizza
 ```
 
+## Encode properties: no comments
+Given a sample.yml file of:
+```yaml
+# block comments don't come through
+person: # neither do comments on maps
+    name: Mike # comments on values appear
+    pets: 
+    - cat # comments on array values appear
+    food: [pizza] # comments on arrays do not
+emptyArray: []
+emptyMap: []
+
+```
+then
+```bash
+yq -o=props -I=0 '... comments = ""' sample.yml
+```
+will output
+```properties
+person.name = Mike
+person.pets.0 = cat
+person.food.0 = pizza
+```
+
+## Encode properties: include empty maps and arrays
+Use a yq expression to set the empty maps and sequences to your desired value.
+
+Given a sample.yml file of:
+```yaml
+# block comments don't come through
+person: # neither do comments on maps
+    name: Mike # comments on values appear
+    pets: 
+    - cat # comments on array values appear
+    food: [pizza] # comments on arrays do not
+emptyArray: []
+emptyMap: []
+
+```
+then
+```bash
+yq -o=props -I=0 '(.. | select( (tag == "!!map" or tag =="!!seq") and length == 0)) = ""' sample.yml
+```
+will output
+```properties
+# comments on values appear
+person.name = Mike
+
+# comments on array values appear
+person.pets.0 = cat
+person.food.0 = pizza
+emptyArray = 
+emptyMap = 
+```
+

usage/xml.md

@@ -6,6 +6,12 @@ Consecutive xml nodes with the same name are assumed to be arrays.
 
 XML content data and attributes are created as fields. This can be controlled by the `'--xml-attribute-prefix` and `--xml-content-name` flags - see below for examples.
 
+{% hint style="warning" %}
+Note that versions prior to 4.18 require the 'eval/e' command to be specified. 
+
+`yq e <exp> <file>`
+{% endhint %}
+
 ## Parse xml: simple
 Notice how all the values are strings, see the next example on how you can fix that.