From 8a264b945ac3d664ef8dc61e755ed9b6c3797513 Mon Sep 17 00:00:00 2001 From: ven Date: Mon, 15 Jan 2024 23:48:29 +0100 Subject: Update cue.html.markdown Try to fix https://github.com/adambard/learnxinyminutes-site/issues/113 --- cue.html.markdown | 52 ++++++++++++++++++++++++++-------------------------- 1 file changed, 26 insertions(+), 26 deletions(-) diff --git a/cue.html.markdown b/cue.html.markdown index 5960c453..a1b76ada 100644 --- a/cue.html.markdown +++ b/cue.html.markdown @@ -12,12 +12,12 @@ CUE is an expressive (but not Turing-complete) JSON superset, exportable to JSON When CUE is exported to JSON, values from every processed file are unified into one giant object. Consider these two files: -```cue +```yaml //name.cue name: "Daniel" ``` -```cue +```yaml //disposition.cue disposition: "oblivious" ``` @@ -40,19 +40,19 @@ disposition: oblivious Notice the C-style comments are not in the output. Also notice that the keys in CUE syntax did not require quotes. Some special characters do require quotes: -```cue +```yaml works_fine: true "needs-quotes": true ``` Unification doesn't just unify across files, it is also a *global merge* of all types and values. The following fails, because the *types* are different. -```cue +```yaml //string_value.cue foo: "baz" ``` -```cue +```yaml //integer_value.cue foo: 100 ``` @@ -66,12 +66,12 @@ foo: conflicting values "baz" and 100 (mismatched types string and int): But even if we quote the integer, it still fails, because the *values* conflict and there is no way to unify everything into a top-level object. -```cue +```yaml //string_value.cue foo: "baz" ``` -```cue +```yaml //integer_value.cue foo: "100" // a string now ``` @@ -85,14 +85,14 @@ foo: conflicting values "100" and "baz": Types in CUE *are* values; special ones that the unification engine knows have certain behavior relative to other values. During unification it requires that values match the specified types, and when concrete values are required, you will get an error if there's only a type. So this is fine: -```cue +```yaml street: "1 Infinite Loop" street: string ``` While `cue export` produces YAML or JSON, `cue eval` produces CUE. This is useful for converting YAML or JSON to CUE, or for inspecting the unified output in CUE itself. It's fine to be missing concrete values in CUE (though it prefers concrete values when emitting CUE when both are available and match), -```cue +```yaml //type-only.cue amount: float ``` @@ -111,7 +111,7 @@ amount: incomplete value float Give it a value that unifies with the type, and all is well. -```cue +```yaml //concrete-value.cue amount: 3.14 ``` @@ -127,7 +127,7 @@ The method of unifying concrete values with types that share a common syntax is Default values may be supplied with a type using an asterisk: -```cue +```yaml // default-port.cue port: int | *8080 ``` @@ -139,7 +139,7 @@ port: 8080 Enum-style options ("disjunctions" in CUE) may be specified with an `|` separator: -```cue +```yaml //severity-enum.cue severity: "high" | "medium" | "low" severity: "unknown" @@ -163,7 +163,7 @@ You can even have disjunctions of structs (not shown, but it works like you'd ex CUE has "definitions", and you can use them like you would variable declarations in other languages. They are also for defining struct types. You can apply a struct of type definitions to some concrete value(s) with `&`. Also notice you can say "a list with type #Whatever" using `[...#Whatever]`. -```cue +```yaml // definitions.cue #DashboardPort: 1337 @@ -208,7 +208,7 @@ more_addresses: CUE supports more complex values and validation: -```cue +```yaml #Country: { name: =~"^\\p{Lu}" // Must start with an upper-case letter pop: >800 & <9_000_000_000 // More than 800, fewer than 9 billion @@ -222,7 +222,7 @@ vatican_city: #Country & { CUE may save you quite a bit of time with all the sugar it provides on top of mere JSON. Here we're defining, "modifying", and validating a nested structure in three lines: (Notice the `[]` syntax used around `string` to signal to the engine that `string` is a constraint, not a string in this case.) -```cue +```yaml //paths.cue // path-value pairs @@ -249,7 +249,7 @@ outer: [string]: inner: int In the same vein, CUE supports "templates", which are a bit like functions of a single argument. Here `Name` is bound to each string key immediately under `container` while the struct underneath *that* is evaluated. -```cue +```yaml //templates.cue container: [Name=_]: { @@ -284,7 +284,7 @@ container: { And while we're talking about references like that, CUE supports scoped references. -```cue +```yaml //scopes-and-references.cue v: "top-level v" b: v // a reference @@ -320,7 +320,7 @@ I changed the order of the keys in the output for clarity. Order doesn't actuall You can hide fields be prefixing them with `_` (quote the field if you need a `_` prefix in an emitted field) -```cue +```yaml //hiddens.cue "_foo": 2 _foo: 3 @@ -346,7 +346,7 @@ Notice the difference between `eval` and `export` with respect to definitions. I Interpolation of values and fields: -```cue +```yaml //interpolation.cue #expense: 90 @@ -372,7 +372,7 @@ cat: { Operators, list comprehensions, conditionals, imports...: -```cue +```yaml //getting-out-of-hand-now.cue import "strings" // we'll come back to this @@ -446,7 +446,7 @@ At this point it's worth mentioning that CUE may not be Turing-complete, but it To that end, CUE supports packages and modules. CUE files are standalone by default, but if you put a package clause at the top, you're saying that file is unifiable with other files "in" the same package. -```cue +```yaml //a.cue package config @@ -454,7 +454,7 @@ foo: 100 bar: int ``` -```cue +```yaml //b.cue package config @@ -508,7 +508,7 @@ configuredBar: 200 The contents of `main.cue` is: -```cue +```yaml //main.cue package main @@ -519,7 +519,7 @@ configuredBar: config.bar `config/a.cue` and `config/b.cue` are files from earlier, except now they've both got `package config` at the top: -```cue +```yaml //a.cue package config @@ -527,7 +527,7 @@ foo: 100 bar: int ``` -```cue +```yaml //b.cue package config @@ -548,4 +548,4 @@ That's it for now. I understand there are more package management features comin Finally, CUE has built-in modules with powerful functionality. We saw one of these earlier, when we imported "strings" and used `strings.ToLower`. Imports without fully-qualified module names are assumed to be built-ins. The full list and documentation for each is here: https://pkg.go.dev/cuelang.org/go/pkg -This has been a condensation of the official docs and tutorials, so go give the source material some love: https://cuelang.org/docs/tutorials/ \ No newline at end of file +This has been a condensation of the official docs and tutorials, so go give the source material some love: https://cuelang.org/docs/tutorials/ -- cgit v1.2.3