Merge branch 'preview' into listing-tweaks

11 files changed, 362 insertions, 0 deletions

diff --git a/src/data/composite/control-flow/exitWithoutDependency.js b/src/data/composite/control-flow/exitWithoutDependency.js
new file mode 100644
index 00000000..c660a7ef
--- /dev/null
+++ b/src/data/composite/control-flow/exitWithoutDependency.js
@@ -0,0 +1,35 @@
+// Early exits if a dependency isn't available.
+// See withResultOfAvailabilityCheck for {mode} options.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+import withResultOfAvailabilityCheck from './withResultOfAvailabilityCheck.js';
+
+export default templateCompositeFrom({
+  annotation: `exitWithoutDependency`,
+
+  inputs: {
+    dependency: input({acceptsNull: true}),
+    mode: inputAvailabilityCheckMode(),
+    value: input({defaultValue: null}),
+  },
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: input('dependency'),
+      mode: input('mode'),
+    }),
+
+    {
+      dependencies: ['#availability', input('value')],
+      compute: (continuation, {
+        ['#availability']: availability,
+        [input('value')]: value,
+      }) =>
+        (availability
+          ? continuation()
+          : continuation.exit(value)),
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/exitWithoutUpdateValue.js b/src/data/composite/control-flow/exitWithoutUpdateValue.js
new file mode 100644
index 00000000..244b3233
--- /dev/null
+++ b/src/data/composite/control-flow/exitWithoutUpdateValue.js
@@ -0,0 +1,24 @@
+// Early exits if this property's update value isn't available.
+// See withResultOfAvailabilityCheck for {mode} options.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import exitWithoutDependency from './exitWithoutDependency.js';
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+
+export default templateCompositeFrom({
+  annotation: `exitWithoutUpdateValue`,
+
+  inputs: {
+    mode: inputAvailabilityCheckMode(),
+    value: input({defaultValue: null}),
+  },
+
+  steps: () => [
+    exitWithoutDependency({
+      dependency: input.updateValue(),
+      mode: input('mode'),
+      value: input('value'),
+    }),
+  ],
+});
diff --git a/src/data/composite/control-flow/exposeConstant.js b/src/data/composite/control-flow/exposeConstant.js
new file mode 100644
index 00000000..e0435478
--- /dev/null
+++ b/src/data/composite/control-flow/exposeConstant.js
@@ -0,0 +1,26 @@
+// Exposes a constant value exactly as it is; like exposeDependency, this
+// is typically the base of a composition serving as a particular property
+// descriptor. It generally follows steps which will conditionally early
+// exit with some other value, with the exposeConstant base serving as the
+// fallback default value.
+
+import {input, templateCompositeFrom} from '#composite';
+
+export default templateCompositeFrom({
+  annotation: `exposeConstant`,
+
+  compose: false,
+
+  inputs: {
+    value: input.staticValue(),
+  },
+
+  steps: () => [
+    {
+      dependencies: [input('value')],
+      compute: ({
+        [input('value')]: value,
+      }) => value,
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/exposeDependency.js b/src/data/composite/control-flow/exposeDependency.js
new file mode 100644
index 00000000..3aa3d03a
--- /dev/null
+++ b/src/data/composite/control-flow/exposeDependency.js
@@ -0,0 +1,28 @@
+// Exposes a dependency exactly as it is; this is typically the base of a
+// composition which was created to serve as one property's descriptor.
+//
+// Please note that this *doesn't* verify that the dependency exists, so
+// if you provide the wrong name or it hasn't been set by a previous
+// compositional step, the property will be exposed as undefined instead
+// of null.
+
+import {input, templateCompositeFrom} from '#composite';
+
+export default templateCompositeFrom({
+  annotation: `exposeDependency`,
+
+  compose: false,
+
+  inputs: {
+    dependency: input.staticDependency({acceptsNull: true}),
+  },
+
+  steps: () => [
+    {
+      dependencies: [input('dependency')],
+      compute: ({
+        [input('dependency')]: dependency
+      }) => dependency,
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/exposeDependencyOrContinue.js b/src/data/composite/control-flow/exposeDependencyOrContinue.js
new file mode 100644
index 00000000..0f7f223e
--- /dev/null
+++ b/src/data/composite/control-flow/exposeDependencyOrContinue.js
@@ -0,0 +1,34 @@
+// Exposes a dependency as it is, or continues if it's unavailable.
+// See withResultOfAvailabilityCheck for {mode} options.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+import withResultOfAvailabilityCheck from './withResultOfAvailabilityCheck.js';
+
+export default templateCompositeFrom({
+  annotation: `exposeDependencyOrContinue`,
+
+  inputs: {
+    dependency: input({acceptsNull: true}),
+    mode: inputAvailabilityCheckMode(),
+  },
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: input('dependency'),
+      mode: input('mode'),
+    }),
+
+    {
+      dependencies: ['#availability', input('dependency')],
+      compute: (continuation, {
+        ['#availability']: availability,
+        [input('dependency')]: dependency,
+      }) =>
+        (availability
+          ? continuation.exit(dependency)
+          : continuation()),
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/exposeUpdateValueOrContinue.js b/src/data/composite/control-flow/exposeUpdateValueOrContinue.js
new file mode 100644
index 00000000..1f94b332
--- /dev/null
+++ b/src/data/composite/control-flow/exposeUpdateValueOrContinue.js
@@ -0,0 +1,40 @@
+// Exposes the update value of an {update: true} property as it is,
+// or continues if it's unavailable.
+//
+// See withResultOfAvailabilityCheck for {mode} options.
+//
+// Provide {validate} here to conveniently set a custom validation check
+// for this property's update value.
+//
+
+import {input, templateCompositeFrom} from '#composite';
+
+import exposeDependencyOrContinue from './exposeDependencyOrContinue.js';
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+
+export default templateCompositeFrom({
+  annotation: `exposeUpdateValueOrContinue`,
+
+  inputs: {
+    mode: inputAvailabilityCheckMode(),
+
+    validate: input({
+      type: 'function',
+      defaultValue: null,
+    }),
+  },
+
+  update: ({
+    [input.staticValue('validate')]: validate,
+  }) =>
+    (validate
+      ? {validate}
+      : {}),
+
+  steps: () => [
+    exposeDependencyOrContinue({
+      dependency: input.updateValue(),
+      mode: input('mode'),
+    }),
+  ],
+});
diff --git a/src/data/composite/control-flow/index.js b/src/data/composite/control-flow/index.js
new file mode 100644
index 00000000..dfc53db7
--- /dev/null
+++ b/src/data/composite/control-flow/index.js
@@ -0,0 +1,9 @@
+export {default as exitWithoutDependency} from './exitWithoutDependency.js';
+export {default as exitWithoutUpdateValue} from './exitWithoutUpdateValue.js';
+export {default as exposeConstant} from './exposeConstant.js';
+export {default as exposeDependency} from './exposeDependency.js';
+export {default as exposeDependencyOrContinue} from './exposeDependencyOrContinue.js';
+export {default as exposeUpdateValueOrContinue} from './exposeUpdateValueOrContinue.js';
+export {default as raiseOutputWithoutDependency} from './raiseOutputWithoutDependency.js';
+export {default as raiseOutputWithoutUpdateValue} from './raiseOutputWithoutUpdateValue.js';
+export {default as withResultOfAvailabilityCheck} from './withResultOfAvailabilityCheck.js';
diff --git a/src/data/composite/control-flow/inputAvailabilityCheckMode.js b/src/data/composite/control-flow/inputAvailabilityCheckMode.js
new file mode 100644
index 00000000..8008fdeb
--- /dev/null
+++ b/src/data/composite/control-flow/inputAvailabilityCheckMode.js
@@ -0,0 +1,9 @@
+import {input} from '#composite';
+import {is} from '#validators';
+
+export default function inputAvailabilityCheckMode() {
+  return input({
+    validate: is('null', 'empty', 'falsy', 'index'),
+    defaultValue: 'null',
+  });
+}
diff --git a/src/data/composite/control-flow/raiseOutputWithoutDependency.js b/src/data/composite/control-flow/raiseOutputWithoutDependency.js
new file mode 100644
index 00000000..03d8036a
--- /dev/null
+++ b/src/data/composite/control-flow/raiseOutputWithoutDependency.js
@@ -0,0 +1,39 @@
+// Raises if a dependency isn't available.
+// See withResultOfAvailabilityCheck for {mode} options.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+import withResultOfAvailabilityCheck from './withResultOfAvailabilityCheck.js';
+
+export default templateCompositeFrom({
+  annotation: `raiseOutputWithoutDependency`,
+
+  inputs: {
+    dependency: input({acceptsNull: true}),
+    mode: inputAvailabilityCheckMode(),
+    output: input.staticValue({defaultValue: {}}),
+  },
+
+  outputs: ({
+    [input.staticValue('output')]: output,
+  }) => Object.keys(output),
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: input('dependency'),
+      mode: input('mode'),
+    }),
+
+    {
+      dependencies: ['#availability', input('output')],
+      compute: (continuation, {
+        ['#availability']: availability,
+        [input('output')]: output,
+      }) =>
+        (availability
+          ? continuation()
+          : continuation.raiseOutputAbove(output)),
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/raiseOutputWithoutUpdateValue.js b/src/data/composite/control-flow/raiseOutputWithoutUpdateValue.js
new file mode 100644
index 00000000..3c39f5ba
--- /dev/null
+++ b/src/data/composite/control-flow/raiseOutputWithoutUpdateValue.js
@@ -0,0 +1,47 @@
+// Raises if this property's update value isn't available.
+// See withResultOfAvailabilityCheck for {mode} options!
+
+import {input, templateCompositeFrom} from '#composite';
+
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+import withResultOfAvailabilityCheck from './withResultOfAvailabilityCheck.js';
+
+export default templateCompositeFrom({
+  annotation: `raiseOutputWithoutUpdateValue`,
+
+  inputs: {
+    mode: inputAvailabilityCheckMode(),
+    output: input.staticValue({defaultValue: {}}),
+  },
+
+  outputs: ({
+    [input.staticValue('output')]: output,
+  }) => Object.keys(output),
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: input.updateValue(),
+      mode: input('mode'),
+    }),
+
+    // TODO: A bit of a kludge, below. Other "do something with the update
+    // value" type functions can get by pretty much just passing that value
+    // as an input (input.updateValue()) into the corresponding "do something
+    // with a dependency/arbitrary value" function. But we can't do that here,
+    // because the special behavior, raiseOutputAbove(), only works to raise
+    // output above the composition it's *directly* nested in. Other languages
+    // have a throw/catch system that might serve as inspiration for something
+    // better here.
+
+    {
+      dependencies: ['#availability', input('output')],
+      compute: (continuation, {
+        ['#availability']: availability,
+        [input('output')]: output,
+      }) =>
+        (availability
+          ? continuation()
+          : continuation.raiseOutputAbove(output)),
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/withResultOfAvailabilityCheck.js b/src/data/composite/control-flow/withResultOfAvailabilityCheck.js
new file mode 100644
index 00000000..a6942014
--- /dev/null
+++ b/src/data/composite/control-flow/withResultOfAvailabilityCheck.js
@@ -0,0 +1,71 @@
+// Checks the availability of a dependency and provides the result to later
+// steps under '#availability' (by default). This is mainly intended for use
+// by the more specific utilities, which you should consider using instead.
+//
+// Customize {mode} to select one of these modes, or default to 'null':
+//
+// * 'null':  Check that the value isn't null (and not undefined either).
+// * 'empty': Check that the value is neither null, undefined, nor an empty
+//            array.
+// * 'falsy': Check that the value isn't false when treated as a boolean
+//            (nor an empty array). Keep in mind this will also be false
+//            for values like zero and the empty string!
+// * 'index': Check that the value is a number, and is at least zero.
+//
+// See also:
+//  - exitWithoutDependency
+//  - exitWithoutUpdateValue
+//  - exposeDependencyOrContinue
+//  - exposeUpdateValueOrContinue
+//  - raiseOutputWithoutDependency
+//  - raiseOutputWithoutUpdateValue
+//
+
+import {input, templateCompositeFrom} from '#composite';
+import {empty} from '#sugar';
+
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+
+export default templateCompositeFrom({
+  annotation: `withResultOfAvailabilityCheck`,
+
+  inputs: {
+    from: input({acceptsNull: true}),
+    mode: inputAvailabilityCheckMode(),
+  },
+
+  outputs: ['#availability'],
+
+  steps: () => [
+    {
+      dependencies: [input('from'), input('mode')],
+
+      compute: (continuation, {
+        [input('from')]: value,
+        [input('mode')]: mode,
+      }) => {
+        let availability;
+
+        switch (mode) {
+          case 'null':
+            availability = value !== undefined && value !== null;
+            break;
+
+          case 'empty':
+            availability = value !== undefined && !empty(value);
+            break;
+
+          case 'falsy':
+            availability = !!value && (!Array.isArray(value) || !empty(value));
+            break;
+
+          case 'index':
+            availability = typeof value === 'number' && value >= 0;
+            break;
+        }
+
+        return continuation({'#availability': availability});
+      },
+    },
+  ],
+});