yq/pkg/yqlib/doc/usage/lua.md

145 lines
1.8 KiB
Markdown
Raw Normal View History

Implement basic Lua output support (#1745) * Implement basic Lua output support Ref #1700 Basic but working serialization to Lua tables. * Escape larger set of characters in Lua output Started with a minimum of replacements, this should be more complete, tho not all substitutions are strictly required in Lua. * Print simple keys unquoted in Lua output String keys that satisfy the requirements for variable names can be used as keys without quotes in tables. * Quote Lua keywords in table keys Keywords are not valid as unquoted keys, thus must be quoted * Make output of unquoted Lua table keys optional Generally safer and simpler to not do it. * Hook up settings for Lua output * Allow special characters in Lua prefix and suffix --lua-suffix='});^M' didn't work, so taking this approach instead * Panic on unhandled YAML Kind in Lua encoder * Handle YAML case varied booleans in Lua encoder * Handle special-case numbers in Lua encoder * Reject unhandled scalar Tags in Lua encoder * Add note about how Lua nil is unsuitable as table key Could add some context tracking in the future to allow rejecting nil in a table key context. * Return error instead of panic in Lua encoder * Add initial test for Lua encoder Boilerplate mostly copied from toml_test.go * Additional Lua output tests * Generate Lua encoder documentation Mostly just for the boilerplate * Convert octal for Lua output Lua doesn't have the 0oNNN syntax for octal integers, only decimal and hexadecimal, hence those can be passed trough as is while octal needs special treatment. * Implement indentation in in Lua output * Respect string Style in Lua encoder Lua has 'single', "double" and [[ long ]] strings. * Expand Lua examples * Output line comments in Lua output * Implement Lua globals output mode
2023-08-11 02:56:49 +00:00
## Basic example
Given a sample.yml file of:
```yaml
---
country: Australia # this place
cities:
- Sydney
- Melbourne
- Brisbane
- Perth
```
then
```bash
yq -o=lua '.' sample.yml
```
will output
```lua
return {
["country"] = "Australia"; -- this place
["cities"] = {
"Sydney",
"Melbourne",
"Brisbane",
"Perth",
};
};
```
## Unquoted keys
Uses the `--lua-unquoted` option to produce a nicer-looking output.
Given a sample.yml file of:
```yaml
---
country: Australia # this place
cities:
- Sydney
- Melbourne
- Brisbane
- Perth
```
then
```bash
yq -o=lua '.' sample.yml
```
will output
```lua
return {
country = "Australia"; -- this place
cities = {
"Sydney",
"Melbourne",
"Brisbane",
"Perth",
};
};
```
## Globals
Uses the `--lua-globals` option to export the values into the global scope.
Given a sample.yml file of:
```yaml
---
country: Australia # this place
cities:
- Sydney
- Melbourne
- Brisbane
- Perth
```
then
```bash
yq -o=lua '.' sample.yml
```
will output
```lua
country = "Australia"; -- this place
cities = {
"Sydney",
"Melbourne",
"Brisbane",
"Perth",
};
```
## Elaborate example
Given a sample.yml file of:
```yaml
---
hello: world
tables:
like: this
keys: values
? look: non-string keys
: True
numbers:
- decimal: 12345
- hex: 0x7fabc123
- octal: 0o30
- float: 123.45
- infinity: .inf
- not: .nan
```
then
```bash
yq -o=lua '.' sample.yml
```
will output
```lua
return {
["hello"] = "world";
["tables"] = {
["like"] = "this";
["keys"] = "values";
[{
["look"] = "non-string keys";
}] = true;
};
["numbers"] = {
{
["decimal"] = 12345;
},
{
["hex"] = 0x7fabc123;
},
{
["octal"] = 24;
},
{
["float"] = 123.45;
},
{
["infinity"] = (1/0);
},
{
["not"] = (0/0);
},
};
};
```