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Update document generation script

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Mike Farah
2021-11-03 15:00:28 +11:00
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operators/traverse-read.md
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This is the simplest (and perhaps most used) operator, it is used to navigate deeply into yaml structures.
## Simple map navigation
Given a sample.yml file of:
```yaml
a:
b: apple
```
then
```bash
yq eval '.a' sample.yml
```
will output
```yaml
b: apple
```
## Splat
Often used to pipe children into other operators
Given a sample.yml file of:
```yaml
- b: apple
- c: banana
```
then
```bash
yq eval '.[]' sample.yml
```
will output
```yaml
b: apple
c: banana
```
## Optional Splat
Just like splat, but won't error if you run it against scalars
Given a sample.yml file of:
```yaml
cat
```
then
```bash
yq eval '.[]' sample.yml
```
will output
```yaml
```
## Special characters
Use quotes with brackets around path elements with special characters
Given a sample.yml file of:
```yaml
"{}": frog
```
then
```bash
yq eval '.["{}"]' sample.yml
```
will output
```yaml
frog
```
## Nested special characters
Given a sample.yml file of:
```yaml
a:
"key.withdots":
"another.key": apple
```
then
```bash
yq eval '.a["key.withdots"]["another.key"]' sample.yml
```
will output
```yaml
apple
```
## Keys with spaces
Use quotes with brackets around path elements with special characters
Given a sample.yml file of:
```yaml
"red rabbit": frog
```
then
```bash
yq eval '.["red rabbit"]' sample.yml
```
will output
```yaml
frog
```
## Dynamic keys
Expressions within \[] can be used to dynamically lookup / calculate keys
Expressions within [] can be used to dynamically lookup / calculate keys
Given a sample.yml file of:
```yaml
b: apple
apple: crispy yum
banana: soft yum
```
then
```bash
yq eval '.[.b]' sample.yml
```
will output
```yaml
crispy yum
```
## Children don't exist
Nodes are added dynamically while traversing
Given a sample.yml file of:
```yaml
c: banana
```
then
```bash
yq eval '.a.b' sample.yml
```
will output
```yaml
null
```
## Optional identifier
Like jq, does not output an error when the yaml is not an array or object as expected
Given a sample.yml file of:
```yaml
- 1
- 2
- 3
```
then
```bash
yq eval '.a?' sample.yml
```
will output
```yaml
```
## Wildcard matching
Given a sample.yml file of:
```yaml
a:
cat: apple
mad: things
```
then
```bash
yq eval '.a."*a*"' sample.yml
```
will output
```yaml
apple
things
```
## Aliases
Given a sample.yml file of:
```yaml
a: &cat
c: frog
b: *cat
```
then
```bash
yq eval '.b' sample.yml
```
will output
```yaml
*cat
```
## Traversing aliases with splat
Given a sample.yml file of:
```yaml
a: &cat
c: frog
b: *cat
```
then
```bash
yq eval '.b[]' sample.yml
```
will output
```yaml
frog
```
## Traversing aliases explicitly
Given a sample.yml file of:
```yaml
a: &cat
c: frog
b: *cat
```
then
```bash
yq eval '.b.c' sample.yml
```
will output
```yaml
frog
```
## Traversing arrays by index
Given a sample.yml file of:
```yaml
- 1
- 2
- 3
```
then
```bash
yq eval '.[0]' sample.yml
```
will output
```yaml
1
```
## Traversing nested arrays by index
Given a sample.yml file of:
```yaml
[[], [cat]]
```
then
```bash
yq eval '.[1][0]' sample.yml
```
will output
```yaml
cat
```
## Maps with numeric keys
Given a sample.yml file of:
```yaml
2: cat
```
then
```bash
yq eval '.[2]' sample.yml
```
will output
```yaml
cat
```
## Maps with non existing numeric keys
Given a sample.yml file of:
```yaml
a: b
```
then
```bash
yq eval '.[0]' sample.yml
```
will output
```yaml
null
```
## Traversing merge anchors
Given a sample.yml file of:
```yaml
foo: &foo
a: foo_a
@@ -398,23 +294,17 @@ foobar:
!!merge <<: *foo
thing: foobar_thing
```
then
```bash
yq eval '.foobar.a' sample.yml
```
will output
```yaml
foo_a
```
## Traversing merge anchors with override
Given a sample.yml file of:
```yaml
foo: &foo
a: foo_a
@@ -435,23 +325,17 @@ foobar:
!!merge <<: *foo
thing: foobar_thing
```
then
```bash
yq eval '.foobar.c' sample.yml
```
will output
```yaml
foo_c
```
## Traversing merge anchors with local override
Given a sample.yml file of:
```yaml
foo: &foo
a: foo_a
@@ -472,23 +356,17 @@ foobar:
!!merge <<: *foo
thing: foobar_thing
```
then
```bash
yq eval '.foobar.thing' sample.yml
```
will output
```yaml
foobar_thing
```
## Splatting merge anchors
Given a sample.yml file of:
```yaml
foo: &foo
a: foo_a
@@ -509,15 +387,11 @@ foobar:
!!merge <<: *foo
thing: foobar_thing
```
then
```bash
yq eval '.foobar[]' sample.yml
```
will output
```yaml
foo_c
foo_a
@@ -525,11 +399,9 @@ foobar_thing
```
## Traversing merge anchor lists
Note that the later merge anchors override previous
Given a sample.yml file of:
```yaml
foo: &foo
a: foo_a
@@ -550,23 +422,17 @@ foobar:
!!merge <<: *foo
thing: foobar_thing
```
then
```bash
yq eval '.foobarList.thing' sample.yml
```
will output
```yaml
bar_thing
```
## Splatting merge anchor lists
Given a sample.yml file of:
```yaml
foo: &foo
a: foo_a
@@ -587,15 +453,11 @@ foobar:
!!merge <<: *foo
thing: foobar_thing
```
then
```bash
yq eval '.foobarList[]' sample.yml
```
will output
```yaml
bar_b
foo_a
@@ -604,25 +466,20 @@ foobarList_c
```
## Select multiple indices
Given a sample.yml file of:
```yaml
a:
- a
- b
- c
```
then
```bash
yq eval '.a[0, 2]' sample.yml
```
will output
```yaml
a
c
```