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readme: Update the JS example #141

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Nov 30, 2021
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readme: Update the JS example #141

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25 changes: 15 additions & 10 deletions readme.md
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Original file line number Diff line number Diff line change
Expand Up @@ -87,8 +87,11 @@ $ node
"", // initial working directory

// import callback: receives a base directory and the imported path string,
// returns a 2-element array of the resolved file path and file contents
(wd, imported) => [wd + "/" + imported, "local bar = 123; bar + bar"])
// returns a tuple of the resolved file path and file contents or file contents resolve method
(wd, imported) => [wd + "/" + imported, "local bar = 123; bar + bar"],
// loader callback: receives the tuple from the import callback and returns the file contents
([path, content]) => content
)
'246bar'
```

Expand Down Expand Up @@ -149,12 +152,12 @@ Some notes on the values used in parts of the pipeline:
but with two modifications. The first is that functions like
`function(a){...}` can still be present in the structure: in Jsonnet you can
pass around functions as values and call then later on. The second is that
object values & array entries are *lazy*: e.g. `[error 123, 456][1]` does not
object values & array entries are _lazy_: e.g. `[error 123, 456][1]` does not
raise an error because the first (erroneous) entry of the array is un-used and
thus not evaluated.

- Classes representing literals extend `sjsonnet.Val.Literal` which in turn extends
*both*, `Expr` and `Val`. This allows the evaluator to skip over them instead of
_both_, `Expr` and `Val`. This allows the evaluator to skip over them instead of
having to convert them from one representation to the other.

## Performance
Expand All @@ -169,13 +172,13 @@ google/jsonnet and google/go-jsonnet, measuring the time taken to
evaluate the `test_suite/` folder (smaller is better):

| | Sjsonnet 0.1.5 | Sjsonnet 0.1.6 |
|:-------------|---------------:|---------------:|
| :----------- | -------------: | -------------: |
| Scala 2.13.0 | 14.26ms ± 0.22 | 6.59ms ± 0.27 |
| Scala 2.12.8 | 18.07ms ± 0.30 | 9.29ms ± 0.26 |

| google/jsonnet | google/go-jsonnet |
|---------------:|------------------:|
| ~1277ms| ~274ms|
| -------------: | ----------------: |
| ~1277ms | ~274ms |

google/jsonnet was built from source on commit
f59758d1904bccda99598990f582dd2e1e9ad263, while google/go-jsonnet was
Expand All @@ -197,18 +200,20 @@ want to reproduce our benchmarks, the pre-configured command line is expected
to be run against databricks/universe @ 7cbd8d7cb071983077d41fcc34f0766d0d2a247d).

Benchmark example:

```
sbt bench/jmh:run -jvmArgs "-XX:+UseStringDeduplication" sjsonnet.MainBenchmark
```

Profiler:

```
sbt bench/run
```

## Laziness

The Jsonnet language is *lazy*: expressions don't get evaluated unless
The Jsonnet language is _lazy_: expressions don't get evaluated unless
their value is needed, and thus even erroneous expressions do not cause
a failure if un-used. This is represented in the Sjsonnet codebase by
`sjsonnet.Lazy`: a wrapper type that encapsulates an arbitrary
Expand Down Expand Up @@ -299,15 +304,15 @@ To publish, run the following commands:
### 0.3.0

- Add `--yaml-debug` flag to add source-line comments showing where each line of YAML came from [#105]()https://github.com/databricks/sjsonnet/pull/105
- Add `objectValues` and `objectVlauesAll` to stdlib [#104](https://github.com/databricks/sjsonnet/pull/104)
- Add `objectValues` and `objectVlauesAll` to stdlib [#104](https://github.com/databricks/sjsonnet/pull/104)

### 0.2.8

- Allow direct YAML output generation via `--yaml-out`
- Do not allow duplicate field in object when evaluating list list comprehension [#100](https://github.com/databricks/sjsonnet/pull/100)
- Fix compiler crash when '+' signal is true in a field declaration inside a list comprehension [#98](https://github.com/databricks/sjsonnet/pull/98)
- Fix error message for too many arguments with at least one named arg [#97](https://github.com/databricks/sjsonnet/pull/97)

### 0.2.7

- Streaming JSON output to disk for lower memory usage [#85](https://github.com/databricks/sjsonnet/pull/85)
Expand Down