Simple json schema generator (#577)

* feat(script): add json schema generator

* feat(readme): add

* fix(script): use right merge operator

modules/to-json-schema/README.md

@@ -0,0 +1,77 @@
+# Notes
+
+- `title` properties are generated from input property names converting all
+  capital letters to lowercase with space before them like:
+  `someImportantKey` -> `some important key`
+- `description` properties are generated from input property names converting all
+  capital letters to lowercase with space before them and appended doc urls like:
+  `someImportantKey` -> `some important key\nhttps://some/documentation`
+- `type` properties are generated from input property values
+- `minimum` properties are generated for input properties containing `width`/
+  `height`/`size` word
+- `default` properties are generated for input properties not starting with
+  `my`/`sample`/`example` words
+- `example` properties are generated for input properties starting with
+  `my`/`sample`/`example` words
+
+# Example
+
+Input JSON:
+
+```json
+{
+    "size": "normal",
+    "myInput": 1,
+    "width": 21,
+    "files": ["test.blend", "test.blend"]
+}
+```
+
+Output JSON schema:
+
+```json
+{
+  "$schema": "http://json-schema.org/draft-07/schema",
+  "title": "config",
+  "description": "A config",
+  "type": "object",
+  "properties": {
+    "size": {
+      "title": "size",
+      "description": "size\nhttps://my-doc",
+      "type": "string",
+      "minimum": 0,
+      "default": "normal"
+    },
+    "myInput": {
+      "title": "my input",
+      "description": "my input\nhttps://my-doc",
+      "type": "number",
+      "examples": [
+        1
+      ]
+    },
+    "width": {
+      "title": "width",
+      "description": "width\nhttps://my-doc",
+      "type": "number",
+      "minimum": 0,
+      "default": 21
+    },
+    "files": {
+      "title": "files",
+      "description": "files\nhttps://my-doc",
+      "type": "array",
+      "uniqueItems": true,
+      "items": {
+        "description": "A file\nhttps://my-doc",
+        "type": "string"
+      },
+      "default": [
+        "test.blend",
+        "test.blend"
+      ]
+    }
+  }
+}
+```

modules/to-json-schema/to-json-schema.nu

@@ -0,0 +1,79 @@
+# Converts specific JSON to JSON schema.
+def to-json-schema [schema: int, url: string, json: string] {
+    if not $schema in [4, 7] {
+        error make { msg: $"'http://json-schema.org/draft-0($schema)/schema' is not supported yet." }
+    }
+    if url == "" {
+        error make { msg: "Documentation url can't be empty." }
+    }
+
+    let schema = $"http://json-schema.org/draft-0($schema)/schema"
+
+    $json | jq 'def to_title: . | gsub("(?<x>[A-Z])"; " \(.x)") | ascii_downcase;
+    def to_description: . | to_title + "\n" + $url;
+    
+    def to_singular:
+        if . | test("^[aeiouy]"; "i") then
+            . | sub("^(?<x>.*?)s\n"; "An \(.x)\n")
+        else
+            . | sub("^(?<x>.*?)s\n"; "A \(.x)\n")
+        end;
+    
+    def wrap: {
+        type: "object",
+        properties: with_entries(
+            if .value | type != "object" then
+                {
+                    key,
+                    value: ({
+                        title: .key | to_title,
+                        description: .key | to_description,
+                        type: (.value | type),
+                        
+                    } +
+                    if .key | test("width|height|size") then
+                        { minimum: 0 }
+                    else
+                        {}
+                    end +
+                    if .value | type == "array" then
+                        {
+                            uniqueItems: true,
+                            items: {
+                                description: .key | to_description | to_singular
+                            }
+                        } *
+                        if .value | length > 0 then
+                            {
+                                items: {
+                                    type: .value[0] | type
+                                }    
+                            }
+                        else
+                            {}
+                        end
+                    else
+                        {}
+                    end +
+                    if .key | test("^([Mm]y|[Ss]ample|[Ee]xample)[A-Z]") then
+                        { examples: [.value] }
+                    else
+                        { default: .value }
+                    end)
+                }
+            else
+                .value = {
+                    title: .key | to_title,
+                    description: .key | to_description
+                } + (.value | wrap) + {
+                    additionalProperties: false
+                }
+            end)
+        };
+    
+    {
+        "$schema": $schema,
+        title: "config",
+        description: "A config"
+    } + (. | wrap)' --arg url $url --arg schema $schema
+}